A.  CRUISE NARRATIVE (A13 and A14)

A.1  Highlights 

                           WHP Cruise Summary Information

         WOCE section designation  A14                    | A13
Expedition designation (ExpoCode)  35A3CITHER3_1          | 35A3CITHER3_2
                                                          |
    Chief Scientists/affiliations  MERCIER/CNRS-LPO*      | ARHAN/IFREMER-LPO**
                            Dates  1995.01.12-1995.02.15  | 1995.02.18-1995.03.02
                             Ship  L'ATALANTE             |
                    Ports of call  Dakar to Cape Town     | Cape Town to Dakar
                                                          |
               Number of stations  107                    | 135
                                                          |
                                          427.41'N       |        421.97'N
  Stations' Geographic boundaries  058.37'W   1803.50'E | 901.69'W   659.35'W
                                         4000.47'S       |       4532.04'S
                                                          |
     Floats and drifters deployed  0
   Moorings deployed or recovered  0
             Contributing Authors  A. Billant, P. Branellec, C. Lagadec
____________________________________________________________________________________

  *DR.HERL MERCIER                                             **DR. MICHEL ARHAN
  Laboratoire de Physique des Oceans            Laboratoire de Physique des Oceans
  IFREMER Centre de Brest                                  IFREMER Centre de Brest
  B.P. 70                                                                  B.P. 70
  Plouzane, 29280                                                  Plouzane, 29280 
  FRANCE                                                                    FRANCE

  TEL:   33-98-22-4286                                          TEL: 33-98-22-4285
  FAX:   +33-98-22-44-96                                      FAX: +33-98-22-44-96
  EMAIL: herle.mercier@ifremer.fr                         EMAIL: marhan@ifremer.fr
____________________________________________________________________________________


                                                                            A13/A14 CTD, CITHER-3

TABLE DES MATIRES

RSUM (SUMMARY)

I    Le Groupe CITHER 3

II   Contributions  l'acquisition des donnes d'hydrologie et  la rdaction 
     de ce recueil.

III  Calibration des mesures CTD-O2 
     1  Acquisition des donnes CTD-O2 
     2  Echantillonnage en mer
     3  Analyse des chantillons de salinit et d'oxygne dissous
        3.1  Salinit
        3.2  Oxygne dissous
     4  Etalonnage de la mesure de pression sur les profils CTD
        4.1  Etalonnage du capteur dans les conditions du laboratoire  20C
             4.2  Influence de la temprature. Effet statique
             4.3  Influence de la temprature. Effet dynamique
             4.4  Correction de la mesure de pression sur les profils CTD et au 
                  niveau des prlvements.
             4.5  Vrifications de la mesure de pression CTD aprs correction
     5  Etalonnage de la temprature sur les profils CTD
        5.1  Mode opratoire
        5.2  Vrification de la mesure de temprature CTD aprs correction
     6  Calibration de la conductivit sur les profils CTD
        6.1  Mode opratoire
        6.2  Stratgie de regroupement des stations de la campagne CITHER 3
             6.3  Bilan de la calibration des profils
             6.4  Vrification des rsultats
     7  Calibration des profils d'oxygne dissous
        7.1  Mode opratoire
        7.2  Units d'oxygne dissous
        7.3  Stratgie de regroupement des stations
        7.4  Bilan de la calibration des profils
        7.5  Vrifcation des rsultats
     8  Bibliographie


IV   Listings et figures des paramtres 'bathysonde'

Les Figures (see PDF report)



A13/A14

RESUME

De mi-janvier  dbut avril 1995 s'est droule la campagne CITHER 3 du 
programme WOCE-France, dans le but d'tudier les coulements aux frontires 
mridiennes du bassin Atlantique Sud-Est,  l'ouest les changes avec les 
Bassins d'Argentine et du Brsil, et  l'est les coulements le long du talus 
continental Africain. Les paramtres hydrologiques et gochimiques requis par 
le Programme Hydrologique de WOCE (WHP) ont t mesurs de la surface au fond  
242 stations situes le long de deux radiales, l'une  9W entre le talus 
continental Ivoirien et la latitude 45S, l'autre de Cape Town  la position 
40S-10E. puis au talus continental Ghanen.  Ce rapport, qui est le deuxime 
volume de la srie des recueils de donnes CITHER 3, prsente les mesures des 
paramtres de la bathysonde (pression, temprature, salinit et oxygne 
dissous). Les mesures des autres paramtres (paramtres 'en route' et 
paramtres gochimiques) seront trouves dans les deux autres volumes.  Le 
volume 1 dcrit galement les objectifs du programme CITHER et de ses trois 
campagnes.


SUMMARY

From mid-January to the beginning of April 1995 the cruise CITHER 3 from the 
WOCE- France programme took place with the purpose of studying the flows at the 
meridional boundaries of the Southeastern Atlantic Basin, in the west the 
exchanges with the Argentine and Brazil Basins, and in the east the flows along 
the African continental slope. The hydrologic and geochemical parameters of the 
WOCE Hydrographic Programme (WHP) were measured at 242 surface to bottom 
stations along two lines, one at 9W from the continental slope of the Ivory 
Coast to latitude 45S, the other one from Cape Town to the location 40S-10E, 
then northward to the Ghanaian continental slope. This report, which 
constitutes volume 2 of the CITHER 3 data reports, presents the CTD-O2 
measurements. The other parameters (underway and geo-chemical parameters) may 
be found in the two other volumes. Volume 1 also describes the general 
objectives of the CITHER programme and its three cruises.

            NOTE: VOLUME 1 OF THIS CRUISE REPORT WAS NEVER PRODUCED

                                                                            A13/A14 CTD, CITHER-3

I  LE GROUPE CITHER 3

Le programme CITHER* est l'une des contributions Franaises du programme 
international WOCE (World Ocean Circluation Experiment). Son objectif est de 
raliser cing radiales d'hydrologie/gochimie lgre du rseau WHP (WOCE 
Hydrographic Programme) dans l'Atlantique Sud, et d'en analyser les rsultats, 
indpendamment, puis en assoication avec les donnes recueillies par d'autres 
pays.

L'objet de la campagne CITHER 3 (figure I-1) tait de raliser les radiales A13 
et A14 du WHP, deux lignes mridiennes dans le Bassin Atlantique Sud-Est, l'une 
 la longitude nominale 9W, l'autre le long du continent Africain  une 
distance du talus continental voisine de 600 km. Une radiale transverse reliant 
l'extrmit sud de A13 au talus continental au large de Cape Town a galement 
t ralise.  Cette campagne, qui s'est droule sur le Navire Ocanographique 
L'ATALANTE, a bnfici d'une coopration troite entre plusieurs laboratoires. 
La coordination en a t assure par Michel Arhan (IFREMER/LPO), galement Chef 
de Mission de la deuxime partie de la campagne (ligne A13), Herl Mercier 
(CNRS/LPO) tant Chef de Mission de la premire partie (ligne A14). Les mesures 
des divers paramtres taient sous la responsabilit scientifique des 
chercheurs don't les noms sont indiqus dans le tableau I-1 ci-dessous.


TABLEAU I-1: Chercheurs du groupe CITHER 3 responsables des divers types de 
             mesures.
                                  | 1re partie (A14)                  | 2me partie (A13)
----------------------------------|------------------------------------|------------------------------------
Mesures d'hydrologie              | Herl Mercier        (CNRS/LPO)    | Michel Arhan     (IFREMER/LPO)
  (bathsonde et prlvements)     |                                    |
Analyses des sels nutritifs       | Xos Alvarez Salgado (IIM/Vigo)    | Pascal Morin     (LOC/UBO)
Analyses des chlorofluoromthanes | Laurent Mmery       (CNRS/LODYC)  | Laurent Mmery   (CNRS/LODYC)                     
Prlvements Hlium 3/Tritium     | Wolfgang Roether     (Univ. Brme) | Wolfgang Roether (Univ. Brme)
CO2 total                         | Linda Bingler        (BPNL/Sequim) | Linda Bingler    (BPNL/Sequim)
pH, Alcalinit                    | Aida Fernndez Ros  (IIM/Vigo)    | Melchor Gonzalez (Univ. Las Palmas)


La campagne CITHER 3 a t finance par l'IFREMER et le CNRS  travers le 
Programme national d'Etudes de la Dynamique du Climat (PNEDC). L'IIM/Vigo, 
l'Universit de Bretagne Occidentale, l'Universit de Brme, l'Universit de 
Las Palmas, et le BPNL/Sequim y ont galement contribu. Nous remercions le 
Commandant Gourmelon et l'quipage de l'ATALANTE pour leur concours prcieux au 
cours de cette campagne.


FIGURE I-1: Carte des stations d'hydrologie/gochimie lgre ralises pendant   
            la campagne CITHER 3.

                                                                            A13/A14 CTD, CITHER-3


II  CONTRIBUTIONS A L'ACQUISITION DES DONNEES D'HYDROLOGIE ET A LA REDACTION DE 
    CE RECUEIL.

Ce rapport de donnes consacr aux mesures de la sonde CTD-O2 de la campagne 
CITHER 3 est le deuxime des trois volumes consacrs  cette campagne. Le 
premier volume contient une prsentation d'ensemble de la campagne et les 
rsultats des mesures 'en route' des paramtres mtorologiques, de la 
bathymtrie, et du courant par courantomtrie Doppler de coque.

Le troisime volume prsente les mesures des paramtres chimiques de base du 
programme WOCE, effectues sur prlvements d'eau: salinit, oxygne dissous, 
sels nutritifs, et frons. Il contient galement les rsultats des paramtres 
du systme carbonique.

Les noms et affiliations de l'ensemble du personnel scientifique embarquant 
ayant contribu au cours de la campagne  l'acquisition des donnes de 
bathysonde ou aux analyses de salinit et d'oxygne dissous en vue de leur 
calibration, sont lists dans le tableau II-1 ci-dessous.

La prparation technique de l'quipement d'hydrologie (bathysondes, rosettes de 
prlvement) et d'analyses de salinit et d'oxygne dissous avait t assure 
avant la campagne par le groupe technique du Laboratoire de Physiques des 
Ocans (A. Billant, P. Branellec, J.P. Gouillou, assists d'autres collgues). 
Les talonnages pr- et post- campagne des bathysondes et des thermomtres et 
pressiomtres  renversement ont t raliss au Laboratoire de Mtrologie du 
Centre de Brest d'IFREMER par M. Cambon. Aprs la campagne, la calibration des 
donnes a t assure par A. Billant et P. Branellec. Ce rapport a t prpar 
au Laboratoire de Physique des Ocans par A. Billant et P. Branellec (partie 
III), et C. Lagadec (partie IV). J. Le Gall et P. Le Bot ont assur la frappe 
du texte et la prparation des figures. 


TABLEAU II-1: Liste du personnel scientifique ayant contribu  l'acquisition 
              des donnes de bathysonde (CTD) ou aux analyses de salinit (S) et 
              d'oxygne dissous (O2) au cours de la campagne CITHER 3.

                                                                PARTIE DE
NOM                   | CONTRIBUTION         | LABORATOIRE    | LA CAMPAGNE
----------------------|----------------------|----------------|------------
BILLANT, Andr        | S, O2                | IFREMER/LPO    |   1       
BAURAND, Franois     | O2                   | ORSTOM/Cayenne |   1       
CROSNIER, Laurence    | CTD                  | UBO/LPO        |   1       
FLORENCHIE, Pierre    | CTD                  | IMG/Grenoble   |   1       
GARNIER, Valrie      | CTD                  | UBO/LPO        |   1       
GIORDMAINA, Robert    | CTD                  | IFREMER/SISMER |   1       
GOUILLOU, Jean-Pierre | CTD/Electronique     | IFREMER/LPO    |   1       
HEMON, Catherine      | CTD                  | IFREMER/LPO    |   1       
KOFFI, Fofi          | CTD, S               | CRO/Abidjan    |   1       
LEIZOUR, Stphane     | CTD                  | IFREMER/LPO    |   1       
LUX, Muriel           | S                    | IFREMER/LPO    |   1       
MERCIER, Herl        | Chef de Mission, CTD | CNRS/LPO       |   1       
McNALLY, Stphanie    | CTD                  | MIT/WHOI       |   1       
ARHAN, Michel         | Chef de Mission, CTD | IFREMER/LPO    |       2
BRANELLEC, Pierre     | S, O2                | IFREMER/LPO    |       2
DECK, Murielle        | O2                   | CNRS/LPO       |       2
GAVART, Michel        | CTD, S               | CNRM/Toulouse  |       2
GIRARDOT, Jean-Pierre | CTD/Electronique     | UBO/LPO        |       2
LAGADEC, Catherine    | CTD                  | IFREMER/LPO    |       2
LE BOT, Philippe      | CTD                  | IFREMER/LPO    |       2
LE GRAND, Pascal      | CTD                  | IFREMER/LPO    |       2
PAILLET, Jrme       | CTD                  | SHOM/LPO       |       2
PEDEN, Olivier        | CTD                  | IFREMER/LPO    |       2
REGNAULT, Jean-Pierre | CTD                  | IFREMER/LPO    |       2
REYNAUD, Thierry      | S                    | UBO/LPO        |       2
SEARSON, Sarah        | CTD                  | CNRS/LPO       |       2

                                                                            A13/A14 CTD, CITHER-3

Les significations des acronymes utiliss dans le tableau II-1 et dans le texte 
sont les suivantes:

CITHER:      Circulation THERmohaline
ORSTOM:      Institut Franais de Recherche Scientifique pour le Dveloppement 
             en Coopration
IFREMER:     Institut Franais de Recherche pour l'Exploitation de la Mer
CNRS:        Centre National de la Recherche Scientifique
PNEDC:       Programme National d'Etude de la Dynamique du Climat
SISMER:      Service d'Information Scientifique pour la Mer
LPO:         Laboratoire de Physique des Ocans
LODYC:       Laboratoire d'Ocanographie Dynamique et de Climatologie
UBO:         Universit de Bretagne Occidentale
IIM/Vigo:    Instituto de Investigaciones Marinas/ Vigo (Espagne)
BPNL/Sequim: Battelle Pacific Northwest Laboratories/ Sequim (USA)
CNRM:        Centre National de la Recherche en Mtorologie


Des copies de ce rapport ainsi que des volumes 1 et 3 peuvent tre obtenues 
auprs de:
             Andr Billant
             Laboratoire de Physiques des Ocans
             IFREMER/Centre de Brest
             B.P. 70
             29280 Plouzan
             France
             e-mail: andre.Billant@ifremer.fr

                                                                            A13/A14 CTD, CITHER-3

III  CALIBRATION DES MESURES CTD-O2 
     (A. Billant et P. Branellec, Laboratoire de Physique des Ocans)


1.  ACQUISITION DES DONNES CTD-O2 

242 stations ont t ralises au cours de la campagne CITHER 3 avec une sonde 
de type Neil-Brown Mark IIIB (numro de srie 2782).  La campagne, compose de 
deux parties, a t effectue  bord du N/O L'ATALANTE:

   A14: stations 1  107 entre Dakar et Cape Town,
   escale de 4 jours  Cape Town,
   A13; stations 109  243 entre Cape Town et Dakar.

La figure III-1 reprsente la position gographique des stations.

En dbut de campagne, un ADCP (Acoustic Doppler Currentmeter Profiler) tait 
mont dans le chssis bathysonde pour obtenir un profil de courant 
paralllement au profil CTD O2: cet instrument limite  30 le nombre de 
bouteilles de prlvement.  La premire radiale a t effectue dans ces 
conditions bien que l'ADCP soit devenu inoprationnel aprs la station 17: ceci 
constitue l'incident majeur de cette premire partie de campagne.

Au cours de l'escale de Cape Town un ADCP de rechange a t livr. Il tait 
dcud de ne pas l'utiliser avant d'atteindre le voisinage de 'lquateur 
(station 216 et suivantes) ce qui permettait de monter 32 bouteilles pour le 
dbut de la deuxime partie (stations 109  215). Des incidents plus nombreux 
sont  signaler dans cette partie:

   'coques' dans le cble lectroporteur, ce qui nous a oblig  couper
    l'extrmit du cble  plusieurs reprises entre les stations 137 et 161,
   mauvais fonctionnement du dclencheur de bouteilles  la station 120,
   droutage du navire vers Walvis Bay aprs la station 162 pour 
    dbarquer un bless avant de poursuivre la radiale.

Certaines stations taient destines  raliser des 'blancs' pour traceurs ou 
tudier la rptabilit des analyses chimiques: c'est le cas des stations 45, 
160 et 211. La station 194 a t rajoute au rseau initial pour multiplier le 
nombre d'chantillons entre la surface et la profondeur de 1000 mtres dans la 
rgion du minimum d'oxygne subquatorial.

Les signaux de la sonde CTD-O2 sont transmis au systme d'acquisition 
d'hydrologie du Laboratoire de Physique des Ocans (L.P.O.). Ce systme, conu 
autour d'une station de travail UNIX, permet en temps rel de visualiser les 
diffrents paramtres mesurs et calculs sur les profils tout en contrlant la 
qualit du signal transmis par la sonde. L'ensemble des donnes transmises par 
la sonde  la cadence de 32 cycles par seconde est sauvegard sur disque. Aprs 
chaque station, un programme de traitement permet d'obtenir un profil de 
donnes rduites et valides tous les dcibars selon une procdure dcrite dans 
Billant (1985). La validation consiste  comparer chaque paramtre d'un cycle  
sa valeur au cycle prcdent: le cycle est limin si la nouvelle valeur 
diffre de la prcdente de: 

        0.5 dbar en pression (P),
        0.032C pour 0<P<1500 ou 0.005  P>1500 en temprature,
        0.032 mmho/cm pour 0<P<1500 ou 0.005  P>1500 en conductivit,
        0.010  A en courant oxygne,
        0.3C en temprature oxygne.


Une moyenne arithmtique est calcule pour chaque paramtre aux niveaux entiers 
de pression  condition d'avoir valid 25% du nombre thorique de mesures dans 
l'intervalle de 1 dbar (32 pour un profil ralis  un mtre par seconde). De 
cette manire, le nomber de niveaux rduits obtenu sur chaque profil de la 
campagne CITHER 3 est toujours suprieur  99,75% du nombre thorique. Le 
profil monte de la sonde tant perturb, tant par les arrts de la sonde pour 
fermer les bouteilles que par le sillage du chssis, seul le profil descente 
est exploit.

                                                                            A13/A14 CTD, CITHER-3

2.  ECHANTILLONNAGE EN MER

La rosette de prlvement PASH 6000 utilise a t conue au L.P.O. 
Initialement dveloppe en 1984, pour supporter 16 bouteilles, elle a t 
quipe d'un deuxime tage de prlvement en prvision des campagnes WOCE 
portant ainsi sa capacit  32 bouteilles de 8 litres: lorsque le chssis est 
quip de l'ADCP, le nombre de bouteilles est limit  30.

Les bouteilles sont fermes au cours de la remonte de la sonde aprs arrt aux 
niveaux de prlvement. Ces niveaux sont rpartis entre le fond et la surface 
de manire  chantillonner toutes les masses d'eau. L'cart entre deux 
chantillons est au maximum de 300 mtres: la figure III-2 montre 
l'chantillonnage effectu pendant la campagne CITHER 3.

Ds la remonte en surface, les chantillons sont recueillis dans chaque 
bouteille.  Ils serviront pour les diffrentes analyses effectues  bord. 
L'ordre de prlvement des types d'chantillons est celui prconis par les 
instructions de WOCE. L'chantillonnage se fait successivement dans les 
bouteilles de 1  32.

Au cours de la campagne 7007 mesures de salinit et 7033 mesures d'oxygne 
dissous ont t effectues  bord.

Pour estimer l'erreur sur les mthodes analytiques, on a effectu un (ou 
plusieurs) 'double'  chaque station en dclenchant la fermeture de deux 
bouteilles au mme niveau de prlvement. Le niveau des doublets tait dcal  
chaque station. Nous disposons de 308 doublets en salinit et 331 doublets en 
oxygne.

Trois thermomtres  renversement, de type SIS, sont placs sur les bouteilles 
dclenches au fond pour contrler la mesure de temprature CTD: les trois 
insturments ont t dtriors avant la fin de la campagne. Un pressiomtre de 
mme type tait mont sur la bouteille 17 (premire bouteille du deuxime 
tage) pour vrifier le niveau de sa fermeture.

                                                                            A13/A14 CTD, CITHER-3

3.   ANALYSE DES CHANTILLONS DE SALINIT ET D'OXYGNE DISSOUS

3.1. SALINIT

Les chantillons sont recueillis aprs trois rinages successifs dans des 
flacons de 125 ml dont l'tanchit est assure par un joint en caoutchouc. Ds 
la fin des prlvements, les chantillons sont placs dans le conteneur 
d'analyses dont la temprature, contrle est fixe  201C. Les chantillons 
sont analyss 20  30 heures aprs le prlvement pour leur permettre 
d'atteindre un quilibre thermique.

La salinit des chantillons est dtermine d'aprs l'quation PSS 78 (UNESCO, 
1981). Le salinomtre est standardis en utilisant des ampoules d'eau normale 
du lot P 125 (K15=0.99982) fabriqus  WORMLEY le 1er aot 1993: pendant toute 
la campagne, la temprature du bain thermostat est fixe  21C.

Tous les jours, avant chaque srie d'analyses, la standardisation de l'appareil 
est vrifie puis ajuste si ncessaire. Aprs l'analyse des chantillons d'une 
station, la standardisation est vrifie par une nouvelle ampoule d'eau normale 
pouis consigne sur la fiche d'analyses. Pour chaque chantillon, trois 
rinages successifs de la cellule sont effectus avant de faire deux ou trois 
lectures spares  chaque fois par un rinage.

Tous les chantillons de la campagne ont t analyss avec le mme salinomtre 
de type PORTASAL. La stabilit de l'appareil a t remarquable pendant la dure 
de la campagne: au cours de chacune des deux parties il a t rarement 
ncessaire d'ajuster sa standardisation. La salinit de l'eau normale a vari 
au maximum de 0.0009 aprs une journe d'analyses soit environ 130 
chantillons: les mesures de salinit ont t corriges en admettant que la 
drive est linaire.

La rptabilit des prlvements et analyses a t vrifie  quelques stations 
en cours de campagne en fermant un grand nombre de bouteilles au mme niveau. 
Le tableau suivant regroupe les rsultats:


   STATION                            |    45      |    160    |    211
   -----------------------------------|------------|-----------|-----------
   Niveau de fermeture des bouteilles | 3000       | 3200      | 3000
   Nombre de bouteilles               |   30       |   16      |   15
   Valeur moyenne de la salinit      |   34.8898  |   34.8695 |   34.9087
   Ecart maximum  la moyenne         |    0.004   |    0.004  |    0.004
   Ecart-type                         |    0.0015  |    0.0016 |    0.0016


Toutes les valeurs de salinit se trouvent  0.004 de la valeur moyenne et 
l'cart-type obtenu pour chacune de ces sries permet de dduire que la 
rptabilit des mesures de salinit de la campagne est systmatiquement 
infrieure  0.0020 dans le cas de prlvements dans une masse d'eau homogne.

La figure III-3 montre les carts de salinit obtenus sur les doublets de la 
campagne: ils ont t raliss de manire continue, du dbut  la fin,  tous 
les niveaux de prlvement.

Les carts des deux mesures de salinit ont t tudis pour 308 doublets et la 
figure III-4 en prsente l'histogramme. On observe que dans 52% des cas l'cart 
de salinit mesure sur les deux bouteilles est infrieur  0.001 et dans 88% 
des cas infrieur  0.003 et l'cart-type est de 0.00199. Ces rsultats sont 
obtenus pour l'ensemble des chantillons prlevs entre le fond et la surface 
et sont peu amliors en ne considrant que ceux prlevs  grande profondeur 
pour lesquels l'cart-type est de 0.00192.

                                                                            A13/A14 CTD, CITHER-3

3.2. OXYGNE DISSOUS

Les chantillons pour analyse d'oxygne dissous sont recueillis, aprs les 
chantillons pour dosage du fron et de l'hlium, dans des flacons  bouchon 
plongeur de 120 ml. Aprs remplissage du flacon, la temprature de 
l'chantillon est note avant de laisser dborder trois fois l'quivalent de 
volume du flacon.  Aprs addition successive des deux ractifs et bouchage, une 
agitation est pratique pendant 30 secondes. Ds que les prlvements sont 
effectus, les flacons sont retourns un  un pour remettre en suspension le 
prcipit. Les chantillons sont entreposs dans le conteneur laboratoire  la 
temprature de 20 (1)C puis analyss dans un dlai de 4  24 heures.

Les conditions opratoires et la mthode d'analyse sont conformes aux 
recommandations de WOCE (WOCE Operations Manual, 1991). Aprs acidification 
dans le flacon de prlvement, l'iode libr est dos par une solution de 
thiosulfate de sodium dont la normalit est de l'ordre de 0.02N. Celle-ci est 
prpare en quantit suffisante pour analyser une centaine de stations: sa 
normalit est dtermine tous les jours, avant le dbut des sries d'analyses, 
comparativement  une solution d'iodate de potassium dont la normalit, obtenue 
par pese, est 0.020002.

Le dosage est pilot par un titroprocesseur associ  une lectrode de platine 
qui mesure le potentiel de la raction et contrle la burette de thiosulfate de 
sodium.  Le volume de thiosulfate ncessaire  la rduction de l'iode est 
dduit de la dtermination automatique du point d'inflexion sur la courbe de 
potentiel  l'quivalence.

Les rsultats de dosages effectus sur les prlvements aux stations 'tests' 
(bouteilles fermes  la mme profondeur) sont regroups dans le tableau suivant:


    STATION                            |   45     |  160     |  211
    -----------------------------------|----------|----------|---------
    Niveau de fermeture des bouteilles | 3000     | 3200     | 3000
    Nombre de bouteilles prleves     |   30     |   16     |   15
    Valeur moyenne d'oxygne (ml/l)    |    5.518 |    5.354 |    5.430
    Ecart maximum  la moyenne         |    0.008 |    0.014 |    0.015
    Ecart-type                         |    0.004 |    0.006 |    0.007


On observe que toutes les mesures d'oxygne sont  0.015 ml/l de la valeur 
moyenne. L'cart-type obtenu  chacune de ces stations permet de considrer que 
les mesures d'oxygne de la campagne sont reproductibles  0.010 ml/l prs dans 
le cas de prlvement dans une masse d'eau homogne.

La figure III-5 montre les carts obtenus entre les mesures effectues lors des 
331 doublets: la figure III-6 en prsente des histogrammes. Pour l'ensemble des 
doublets entre le fond et la surface, 52% des carts sont infrieurs  0.005 
ml/l et 86% sont infrieurs  0.015 ml/l pour un cart-type de 0.014 ml/l. En 
liminant les niveaux compris entre la surface et 980 dbar, o la variabilit 
en oxygne est plus importante, les carts sont lgrement amliors car 56% 
sont infrieurs  0.005 ml/l et 90% infrieurs  0.015 ml/l pour un cart-type 
de 0.012 ml/l.

                                                                            A13/A14 CTD, CITHER-3

4.  ETALONNAGE DE LA MESURE DE PRESSION SUR LES PROFILS CTD

La sonde utilise est quipe d'un capteur de pression de type Paine dont la 
rsolution est de 0.1 dbar et, d'aprs le constructeur, le prcision de 6.5 
dbars.  Ce capteur a dj t utilis pour la campagne CITHER 1. Des 
amliorations ont t apportes  l'issue de cette campagne de manire  
rduire l'amplitude et la dure de l'effet d aux chocs thermiques.

De manire habituelle, les capteurs sont talonns avant et aprs la campagne 
au laboratoire de mtrologie de l'IFREMER habilit par le Bureau National de 
Mtrologie (B.N.M.). Le capteur est branch sur un banc balance Desgranges et 
Huot qui dlivre une pression rfrence avec une erreur maximale de 0.75 dbar 
au niveau 6000 dbars.

4.1.  ETALONNAGE DU CAPTEUR DANS LES CONDITIONS DU LABORATOIRE  20C

Plusieurs cycles de monte et descente en pression, par paliers successifs de 
400 dbar, de 0  6000 dbars, sont raliss  la temprature du laboratoire soit 
201C.  Les rsultats obtenus pour le capteur utilis pendant la campagne 
CITHER 3 sont prsents sur la figure III-7 sous forme d'carts entre la 
pression rfrence dlivre par le banc balance et la pression quivalente 
indique par le capteur sur les cycles monte en pression (profil descente de 
la sonde) et descente en pression (profil monte). La rpartition des points 
rsultant des talonnages pr- et post- campagne peut tre corrige par un 
polynme de degr 3: ces rsultats mettent en vidence une excellente stabilit 
du capteur pendant la campagne.

4.2.  INFLUENCE DE LA TEMPRATURE. EFFET STATIQUE

La rponse du capteur est influence par sa temprature interne. La temprature 
ocanique prsente des varts suprieurs  20C entre la surface et le fond. Il 
est donc ncessaire de connatre la temprature interne du capteur en cours de 
profil. Celle-ci est mesure comme paramtre annexe et transmise dans les 
cycles de mesure de la sonde.

L'influence statique de temprature interne du capteur est tudie au 
laboratoire en immergeant la sonde dans un bain d'eau  diffrentes 
tempratures. Aprs stabilisation de la temprature interne du capteur, on 
effectue un cycle de monte puis de descente en pression en relevant 
l'indication du capteur de pression  des paliers spars de 1000 dbar. Cette 
opration est rpte en cinq diffrents points de temprature compris entre 0 
et 30C. La srie d'essais montre que l'influence de la temprature interne est 
du mme ordre de grandeur que celle qui s'apppliquait  la campagne CITHER 1: 
une diffrence de temprature interne de 30C provoque un dcalage de 
l'indication de pression de 5 dbar  toutes les pressions exprimentales.

La temprature interne  un niveau de pression donn (profil descente et 
monte) est dtermine pour l'ensemble des stations de la campagne CITHER 3 en 
utilisant un profil moyen. La correction de temprature statique est ainsi 
obtenue  chaque niveau de pression. L'erreur maximum d'une telle correction 
est obtenue entre 0 et 1000 dbar car c'est  ces profondeurs que la diffrence 
entre les conditions au sud de la radiale et celles  l'quateur est la plus 
importante ; cependant l'erreur y reste infrieure  1.0 dbar. L'erreur est 
infrieure  0.4 dbar lorsque la pression est suprieure  2000 dbar.

La correction de temprature statique applique  la mesure de pression obtenue 
sur les profils CTD reste infrieure  3 dbar.

                                                                            A13/A14 CTD, CITHER-3

4.3.  INFLUENCE DE LA TEMPRATURE. EFFET DYNAMIQUE

Le passage de la thermocline,  la descente et  la monte, provoque une 
variation brutale de temprature. Ce choc thermique, appel influence de 
temprature dynamique, est simul en laboratoire afin d'tudier le comportement 
du capteur qui dpend essentiellement de la qualit de son isolation.

Le capteur a t soumis  une srie de chocs thermiques en immergeant 
brutalement la sonde aprs un sjour  une temprature donne dans un bain plus 
chaud ou plus froid suivant le cas. Les paramtres transmis par la sonde 
(pression, temprature in-situ et temprature interne du capteur de pression) 
sont enregistrs pendant un temps suffisamment long pour tudier le 
comportement du capteur aprs ce phnomne.

Ces exprience permettent de constater que le capteur subit, dans les 
conditions de son utilisation pendant la campagne CITHER 3, un dcalage de 2.0 
dbar 27 minutes aprs un choc thermique de 15C: ce dcalage reste constant 
pendant une dure de 4 heures. Lors de la campagne CITHER 1 le dcalage tait 
de 5, 4 dbars: les amliorations apportes ont donc nettement attnu la 
rponse dynamique  un choc de temprature.

La correction de ce type de choc a t applique  la pression enregistre sur 
les profils de la campagne en admettant que:

   le passage de la thermocline provoque un choc thermique de 15C et donc un 
    dcalage en pression de 2.0 dbar sur le profil descente puis de sens inverse 
    en fin de monte,
   le profil descente est excut  la vitesse de 1 mtre par seconde,
   l'arrt  chaque palier pour fermer la bouteille dure 1 minute.

4.4.   CORRECTION DE LA MESURE DE PRESSION SUR LES PROFILS CTD ET AU NIVEAU DES 
       PRLVEMENTS.

A la correction de l'indication du capteur de pression  la temprature de 20C 
(polynme de degr 3), on ajoute les corrections associes  l'effet statique 
et  l'effet dynamique de la temprature. Sur la figure III-8, le polynme de 
degr 5 visualis permet de minimiser les carts aux points exprimentaux, 
distants de 400 dbar, et d'interpoler la correction aux autres niveaux de 
pression.

4.5.  VRIFICATIONS DE LA MESURE DE PRESSION CTD APRS CORRECTION

Pendant la campagne, l'indication du capteur tait releve en surface, au dbut 
du profil descente et en fin de monte. L'indication du capteur, aprs 
correction par le polynme de degr 5, est tout  fait compatible avec 
l'immersion relle du capteur au dbut de la descente et  la fin de la monte.

L'ATALANTE est un navire qui tient bien sa position en station et le cble est 
fil en gnral en suivant une ligne quasiment verticale. Il est donc possible 
de comparer cette longueur file  chaque station avec la profondeur dduite de 
l'indication du capteur de pression (aprs recalage) au fond. La figure III-9 
reprsente les carts obtenus  chaque station entre ces deux informations. Il 
convient de ngliger les 3 points qui correspondent aux stations o la poulie 
compteuse n'tait pas remise  zro en dbut de station. La distribution des 
points tangente la ligne de base qui correspond  un cble rigoureusement 
vertical quelle que soit la longueur file. Cette figure montre que la pression 
recale est correcte dans toute la gamme de mesure.

On peut donc considrer, comme pour les deux campagnes prcdentes CITHER 1 et 
CITHER 2, tant donn l'excellente stabilit du capteur affect d'une 
correction globale faible, que l'erreur maximale de la mesure de pression sur 
les profils de CITHER 3 est de 2 dbar.

                                                                            A13/A14 CTD, CITHER-3

5.  ETALONNAGE DE LA TEMPRATURE SUR LES PROFILS CTD

La mesure de temprature rsulte de la combinaison d'un thermomtre  
rsistance de platine de type Rosemount avec une thermistance de type Fenwall, 
tels que fournis en version standard. La rsolution de la mesure est de 
0.0005C et la prcision annonce par le constructeur est de 0.005C.

5.1.  MODE OPRATOIRE

Les sondes du LPO sont rgulirement talonnes au laboratoire de mtrologie de 
l'IFREMER avant et aprs chaque campagne. La sonde est totalement immerge dans 
un bain d'eau thermostat dont la stabilit en temprature est strictement 
contrle.  La temprature rfrence du bain est fournie par un thermomtre  
rsistance de platine de type Rosemount plac  proximit immdiate du capteur 
CTD. Ce thermomtre est priodiquement contrl et l'agrment fourni par le 
Bureau National de Mtrologie (B.N.M.). La temprature mesure est exprime 
dans l'chelle EIT 90.  Plusieurs points de mesure sont ainsi contrls en 
relevant l'indication de temprature CTD pour la comparer  la temprature 
rfrence du bain en plusieurs points compris entre 0 et 30C.

La sonde mise en oeuvre pendant la campagne CITHER 3 a t utilise sur de 
nombreuses campagnes depuis 1982: les talonnages successifs ont montr que 
l'indication de temprature n'a pas vari de plus de 0.010C pendant ce temps. 
Les talonnages effectus avant et aprs CITHER 3 sont prsents sur la figure 
III-10 sous forme d'carts entre la temprature de rfrence et la temprature 
indique par le capteur Neil-Brown. L'talonnage qui a prcd la campagne 
confirmait la stabilit observe prcdemment. Au retour, on observe un 
dcalage croissant de 0  0.006C pour une temprature comprise entre 0 et 15C 
et un dcalage constant de l'ordre de 0.010C pour une temprature comprise 
entre 20 et 30C.

Les mesures de temprature obtenues sur les profils de la campagne CITHER 3 
sont corriges en appliquant un polynme de degr 2, dont la courbe est 
prsente sur la figure III-10. Cette courbe minimise les carts obtenus avant 
et aprs la campagne: l'erreur maximale est de 0.003C pour une temprature 
infrieure  15C et de 0.005C si elle est suprieure.
                                                                            A13/A14 CTD, CITHER-3

5.2.  VRIFICATION DE LA MESURE DE TEMPRATURE CTD APRS CORRECTION

Pendant la campagne, la temprature indique par le capteur est compare  
celle lue sur les trois thermomtres SIS au niveau de leur dclenchement  
chaque station. Ceux-ci taient dclenchs  grande profondeur et mesurent en 
gnral une temprature infrieure  3C. Il est donc difficile de vrifier si 
l'cart faible observ entre les deux talonnages (de l'ordre de 0.003C) 
correspond  une drive lente du capteur pendant la campagne ou  un saut 
brutal de la rponse. Cette difficult est renforce par le fait qu'aucun des 
trois thermomtres n'a fonctionn jusqu' la fin de campagne. Les carts 
obtenus, au niveau de chaque thermomtre, sont prsents sur la figure III-11. 
Le thermomtre 499 qui a fonctionn jusqu' la station 150 permet de supposer 
qu'il n'y a pas de drive au cours des deux premiers tiers de la campagne.

Des comparaisons effectues avec les mesures de temprature obtenues au cours 
d'autres campagnes  des stations effectues  une position gographique proche 
n'ont pas permis de lever le doute pour le dernier tiers de la campagne. Il 
faut donc admettre que les valeurs de temprature sur les profils CTD de la 
campagne CITHER 3 sont affectes d'une erreur maximale de 0.003C pour une 
temprature infrieure  15C et peut atteindre 0.005C si elle est suprieure.


6.    CALIBRATION DE LA CONDUCTIVIT SUR LES PROFILS CTD

6.1.  MODE OPRATOIRE

La procdure de calibration, dcrite dans Billant (1985), consiste  comparer 
la conductivit COS indique par la sonde au niveau du prlvement  la 
conductivit in-situ COH dtermine sur les chantillons. La conductivit COS 
est obtenue en calculant une moyenne sur les valeurs transmises par la sonde au 
niveau de fermeture de la bouteille et en appliquant  cette moyenne la 
correction de l'effet de pression et de temprature sur la cellule. La salinit 
de l'chantillon est transforme en conductivit in-situ COH en utilisant les 
valeurs de pression et de temprature corriges de la sonde au niveau du 
prlvement.

Les valeurs de conductivit d'un profil sont corriges en dterminant les 
coefficients C1 et Co d'un polynme de degr 1 pour une station, ou un groupe 
de stations, qui minimisent les carts delta-C=COH - COS. Le polynme est de la 
forme:

                               COR=C1 * COS + Co

Les coefficients retenus rsultent d'itrations successives sur le groupe 
d'chantillons considr. Le processus est stopp lorsque, pour le sous-groupe 
d'chantillons considrs pour le calcul des coefficients, tous les carts delta-C 
sont infrieurs  la valeur delta-Cmax=2.8 * cart-type.

Un premier calcul est ainsi effectu sur l'ensemble des chantillons de la 
campagne. La figure III-12 prsente les carts qui subsistent, au niveau de 
chaque prlvement, station par station et en fonction de la pression.

                                                                            A13/A14 CTD, CITHER-3

6.2.  STRATGIE DE REGROUPEMENT DES STATIONS DE LA CAMPAGNE CITHER 3

Une observation dtaille de la distribution de ces carts sur la figure III-12 
montre qu'un dcoupage par groupe ou par stations individuelles doit mieux 
centrer leur rpartition. Ce dcoupage s'appuie sur les vnements intervenus 
pendant la campagne (escale, interruption d'alimentation lectrique de la sonde 
pour refaire l'extrmit du cble lectroporteur, ...). Aprs ce dcoupage, 
l'homognit des mesures est vrifie en comparant, aux stations limites du 
dcoupage, les diagrammes theta-S de fond.

6.3.  BILAN DE LA CALIBRATION DES PROFILS

Le tableau III-1 regroupe l'ensemble des coefficients C1 et C0 utiliss pour 
corriger les valeurs de conductivit sur les profils de la campagne. Le tableau 
indique galement pour chaque station ou groupe le nombre d'chantillons 
considrs pour le calcul, le nombre de ceux retenus par le processus ainsi que 
la dviation standard qui en rsulte pour le groupe considr.

Pendant la campagne, la salinit a t dtermine sur 7007 chantillons. Le 
processus de calcul en a valid 6187 soit 88.3% d'entre eux ce qui revient  
dire que au niveau de ces chantillons l'cart entre la conductivit de 
l'chantillon et la conductivit corrige sur le profil delta-CR est infrieur  2.8 
fois l'cart-type pour la srie considre.

La figure III-13 reprsente les carts obtenus, aprs recalage des profils de 
la campagne, au niveau de chaque chantillon valid: ces carts sont 
acceptables  toutes les stations et  tous les niveaux de prlvement. L'cart 
maximum observ est de 0.006 mmho/cm et concerne le groupe de stations 40  107.

Les histogrammes de la figure III-14 confirment que pour l'ensemble des niveaux 
de prlvement la distribution des carts est correctement centre. On remarque 
que dans 44% des cas l'cart est infrieur  0.001 mmho/cm tandis que pour 88% 
il est infrieur  0.003.

Le bilan d'ensemble peut tre tabli comme suit: les valeurs de conductivit 
'bathysonde' corrige, compares  la conductivit des 6187 chantillons 
valids indiquent un cart quadratique moyen pour l'ensemble de la campagne de 
0.0019 mmho.cm. La valeur obtenue pour l'ensemble de la campagne est conforme  
l'objectif fix par le programme WOCE (0.002 mmho/cm).

Pour faciliter la comparaison avec les rsutats obtenus sur les doublets, les 
histogrammes d'carts en salinit sont prsents  la figure III-15: l'cart-
type en salinit est de 0.0021. Cette valeur montre qu'on ne pouvait esprer 
mieux de la calibration des profils CTD car elle est quivalente  celle 
obtenue sur les doublets (0.0020).
                                                                            A13/A14 CTD, CITHER-3

TABLEAU III-1: Bilan de la calibration des profils de conductivit de la 
               campagne CITHER 3.

                                  Nombre
                   Nombre     d'chantillons  Dviation 
     Station   d'chantillons   retenus par   standard      Coefficients
    ou Groupe    considrs      le calcul     (0-5700)     C1        C0
    ---------- -------------- --------------  ---------  --------  ------ 
      0 ->  39     1083           944          0.00209   0.998867  0.0188
     40 -> 107     2015          1846          0.00217   0.998700  0.0218
    109 -> 120      264           245          0.00216   0.999327  0.0050
    121 -> 137      540           483          0.00144   0.999268  0.0055
    138              32            31          0.00140   0.999248  0.0055
    139 -> 146      256           238          0.00120   0.999149  0.0062
    147 -> 149       96            90          0.00196   0.999217  0.0051
    150 -> 152       94            88          0.00213   0.999319  0.0067
    153 -> 170      519           452          0.00162   0.999349  0.0017
    171 -> 177      177           152          0.00131   0.999389  0.0016
    178 -> 189      384           329          0.00145   0.999247  0.0052
    190 -> 193      127           109          0.00140   0.999250  0.0073
    194 -> 243     1420          1180          0.00195   0.999228  0.0059

N.B.: Le profil 8 est interrompu  280 mtres du fond.  Le profil 194 est 
      limit a 1000 mtres.


6.4.  VRIFICATION DES RSULTATS

Les stations 25 et 212 de la campagne CITHER 3 ont t effectues  la mme 
position gographique que des stations de la campagne CITHER 1. La figure III-
16 prsente les diagrammes theta-S de fond obtenus  chacune de ces stations. 
Dans le premier cas, les deux diagrammes de CITHER 1 ne sont pas exactement 
superposs ce qui indique que ces stations ont t effectues dans une zone 
gographique o les caractristiques de la masse d'eau de fond sont volutives. 
Le diagramme theta-S obtenu dans cette zone au cours de CITHER 3 prsente un 
dcalage compatible avec la variabilit observe  CITHER 1. Dans le deuxime 
cas, les diagrammes theta theta-S de CITHER 1 et CITHER 3 sont rigoureusement 
superposs: ceci montre que le jeu de donnes recueilli sur les deux campagnes 
est homogne.

Les figures III-17 et III-18 montrent la comparaison de diagrammes theta-S 
extraits des campagnes CITHER 3 et SAVE. Les stations choisies ont t 
effectues  des positions gographiques proches et sont rparties le long de 
chacune des deux radiales de CITHER 3. Dans les deux premiers cas, les 
diagrammes se superposent.  Dans les deux autres, on peut admettre que le 
dcalage observ est compatible avec une variabilit des caractrisitiques des 
masses d'eau.

La figure III-19 prsente deux cas de comparaison entre les diagrammes theta-S 
obtenus sur trois campagnes  une mme position gographique. Ces positions 
sont choisies dans une zone gographique dans laquelle la masse d'eau de fond 
est peu volutive.  Dans les deux cas, la superposition des diagrammes est 
correcte.

Ces figures rvlent un trs bon accord entre les mesures de la campagne CITHER 
3 et celles des campagnes CITHER 1, SAVE 2 et OCEANUS 133.

                                                                            A13/A14 CTD, CITHER-3

7.    CALIBRATION DES PROFILS D'OXYGNE DISSOUS

7.1.  MODE OPRATOIRE

La teneur en oxygne dissous OXYC, exprime en ml/l, est calcule  partir des 
informations OC et OT transmises par le capteur en utilisant la formule 
prconise par Millard (1982).


                OXYC=soc*OC*OXSAT*e^(oxtc (oxc1*T+oxc2(OT-T)+oxpc*P)) 

                                             \                 \
             OC: courant oxygne              |                 |
                                              } capteur Beckman |
             OT: temprature de l'lectrolyte |                 | transmis
                                             /                  } par la sonde 
                                                                | Neil-Brown
             P: mesure pression corrige                        |
             T: temprature corrige                            |
                                                               /  

        soc, oxpc, oxtc, oxc1, oxc2: caractristiques du capteur Beckman
        OXSAT: oxygne  saturation calcul par la mthode Benson et Krause 
               (1984)


La mthode utilise, dcrite dans Billant (1985), consiste  ajuster les 
valeurs d'oxygne dissous (OXYC), calcules par la mthode prcdente sur le 
profil descente, sur la valeur d'oxygne dtermine par voie chimique sur les 
chantillons (OH) prlevs au cours de la monte. Les mesures de la sonde en 
cours de descente sont moyennes dans une tranche d'eau de 15 dbars centre sur 
la valeur de pression au niveau du prlvement.

Les coefficients, caractristiques du capteur Beckman, sont dtermins, pour un 
ensemble d'chantillons, en utilisant des itrations successives bases sur un 
principe similaire  celui de la condictivit. Les caractristiques du capteur 
sont ainsi dtermines pour une station ou un groupe de stations.

7.2.  UNITS D'OXYGNE DISSOUS

L'unit utilise dans la procdure de calibration et dans les reprsentations 
graphiques de ce rapport est exprime en millilitres par litre (ml/l).

La temprature des chantillons lors de leur fixation en mer a t releve. On 
en dduit la densit de l'chantillon, et la teneur en oxygne dissous peut 
tre convertie en micromoles par kilogramme (mol/kg). Les profils de la 
campagne sont galement recals dans cette unit en utilisant le mme dcoupage 
par station ou groupe de stations.

Les donnes d'oxygne dissous du capteur 'bathsonde' sont donc produites dans 
les deux units.

7.3.  STRATGIE DE REGROUPEMENT DES STATIONS

Une premire dtermination des 'caractristiques' du capteur sur l'ensemble des 
chantillons de la campagne permet d'observer les diffrentes phases de son 
comportement. La figure III-20 prsente les rsultats de cette calibration 
globale sous forme d'carts de la valeur d'oxygne mesur analytiquement sur 
les chantillons (OH) et la valeur obtenue sur le profil descente de la sonde 
(OXYC).  La distribution des carts sur cette figure permet de constater que 
les escales proboquent une modification importante de la rponse du capteur 
d'oxygne.

Chacune de ces phases doit donc tre considre sparment et des dcoupages 
dans chacune d'elles permettent d'obtenir pour chacune des stations de la 
campagne un profil d'oxygne dissous bien recal sur les vaeurs d'oxygne 
dissous obtenues par analyse chimique.

7.4.  BILAN DE LA CALIBRATION DES PROFILS

Le tableau III-2 regroupe l'ensemble des valeurs caractristiques des 
coefficients utilises pour recaler les profils de la campagne. Ces tableaux 
indiquent, pour chaque station ou groupe de stations, le nombre d'chantillons 
considrs, le nombre de ceux qui sont valids ainsi que la dviation standard 
dans trois intervalles de pression.

La figure III-21 montre les carts finaux, aprs recalage des profils, entre 
les valeurs d'oxygne fournies par les chantillons et par la sonde sur le 
profil descente au niveau du prlvement. La distibution de ces carts est bien 
centre et acceptable pour chacune des stations de la campagne.

Cette rpartition en fonction de la pression montre qu'elle est correcte  tous 
les niveaux de prlvements.

                                                                            A13/A14 CTD, CITHER-3

TABLEAU III-2: Bilan de la calibration des profils d'oxygne dissous de la 
               campagne CITHER 3

                             Nombre                                
              Nombre     d'chantillons    Dviation standard                Coefficients
 Station  d'chantillons   retenus par  -------------------------  -------------------------------
ou Groupe   considrs      le calcul   0-5700  0-1000  1000-5700    SOC     OXPC      OXTC   OXC2
--------- -------------- -------------- ------  ------  ---------  ------  --------  -------  -----
  1 -> 6      105             91        0.051   0.057   0.039      0.0524  0.000129  -0.0346  0.339
     7         30             28        0.024   0.027   0.024      0.0492  0.000141  -0.0264  0.742
  8 -> 10      90             84        0.032   0.037   0.030      0.0483  0.000150  -0.0265  0.765
 11 -> 13      90             77        0.025   0.033   0.023      0.0493  0.000147  -0.0277  0.605
 14 -> 16      90             81        0.030   0.050   0.025      0.0498  0.000147  -0.0278  0.556
 17 -  18      60             52        0.027   0.034   0.025      0.0502  0.000146  -0.0282  0.690
 19 -> 21      90             80        0.033   0.050   0.028      0.0494  0.000147  -0.0261  0.825
 22 -> 27     179            155        0.033   0.046   0.028      0.0500  0.000148  -0.0280  0.633
 28 -> 39     357            301        0.032   0.046   0.024      0.0506  0.000144  -0.0281  0.676
    40         30             28        0.019   0.021   0.018      0.0500  0.000145  -0.0278  0.917
    41         30             27        0.052   0.076   0.033      0.0496  0.000151  -0.0272  0.696
    42         29             26        0.020   0.023   0.019      0.0502  0.000146  -0.0269  0.793
 43 -> 100   1721           1573        0.039   0.053   0.029      0.0511  0.000144  -0.0291  0.781
101            30             28        0.032   0.043   0.025      0.0533  0.000150  -0.0311  0.653
102 -> 107    178            163        0.040   0.048   0.035      0.0557  0.000142  -0.0329  0.695
    109        32             28        0.026   0.040   0.021      0.0557  0.000154  -0.0275  0.642
110 -> 120    233            200        0.043   0.060   0.031      0.0567  0.000138  -0.0298  0.767
121 -> 153    989            892        0.031   0.044   0.026      0.0558  0.000141  -0.0302  0.811
    138        32             31        0.037   0.069   0.023      0.0541  0.000145  -0.0291  0.957
    147        32             32        0.029   0.054   0.015      0.0545  0.000144  -0.0306  0.744
154 -> 162    272            248        0.035   0.050   0.029      0.0545  0.000142  -0.0298  0.709
163 -> 170    214            186        0.035   0.051   0.028      0.0588  0.000131  -0.0299  0.849
171 -> 215   1374           1224        0.032   0.044   0.028      0.0579  0.000133  -0.0286  0.676
216 -> 230    429            370        0.029   0.037   0.026      0.0559  0.000138  -0.0276  0.779
231 -> 243    317            285        0.040   0.049   0.035      0.0569  0.000135  -0.0279  0.673

N.B. Le profil 8 est interrompu  280 mtres du fond. Le profil 194 est limit 
      1000 mtres.


Les histogrammes de la figure III-22 confirment que la distribution est 
correctement centre pour l'ensemble des niveaux de prlvement et plus 
particulirement aux pressions suprieures  1000 dbars.

Pour l'ensemble de la campagne CITHER 3, 6290 chantillons parmi les 7033 
analyss, soit 89.4%, ont t utiliss et valids pour recaler les profils 
'bathysonde' d'oxygne dissous. Les carts en oxygne sont infrieurs  0.025 
ml/l dans 60.2% des cas et infrieurs  0.075 ml/l pour 95.5%, ceci donne une 
dviation standard de 0.035 ml/l.

En ne considrant que la partie de profil d'oxygne suprieure  980 dbars, 
soit 4644 chantillons, les carts sont infrieurs  0.025 ml/l pour 68.5% et 
infrieurs  0.075 ml/l pour 98.2%. L'cart quadratique moyen est reeduit  
0.028 ml/l.

L'histogramme des carts finaux exprims en micromole/kg est prsent sur la 
figure III-23. Dans cette unit, la dviation standard est de 1.5mole/kg pour 
la totalit du profil, elle est rduite  1.2 mole/kg pour la partie 
suprieure  980 dbars.
                                                                            A13/A14 CTD, CITHER-3

7.5.  VRIFCATION DES RSULTATS

Les comparaisons en oxygne dissous sont effectues aux mmes stations et 
campagnes que celles utilises au chapitre prcdent (paragraphe 6.4).

La figure III-24 prsente une comparaison des profils de CITHER 1 et CITHER 3.  
Dans les deux cas, on peut faire les constatations suivantes:

   les profils de CITHER 3 sont bien cals sur les valeurs d'oxygne mesures 
    sur les chantillons,
   un dcalage de l'ordre de 0.1 ml/l,  pression supieure  2000 dbars, est 
    observ entre les profils des deux campagnes.

Dans les figures suivantes III-25, III-26 et III-27, les profils et les mesures 
d'oxygne dissous de la campagne CITHER 3 sont compars aux valeurs d'oxygne 
dissous mesures sur les chantillons et extraites des diffrentes campagnes 
SAVE.  Ces figures confirment que les profils de CITHER 3 sont bien cals sur 
les mesures chimie de la campagne et que les valeurs de celles-ci sont trs 
proches des valeurs mesures lors des diffrentes campagnes SAVE.

En conclusion, on peut supposer que les dcalages observs sur la figure III-
24, entre CITHER 1 et CITHER 3, correspondent  une ralit. Les trois figures 
suivantes prouvent que dans diffrentes autres zones gographiques les mesures 
d'oxygne dissous de la campagne CITHER 3 ('bathysonde' et 'bouteilles') sont 
en trs bon accord avec les mesures des campagnes SAVE.


8.  BIBLIOGRAPHIE

Benson, B.B. and D. Krause, Jr., 1984.  The concentration and isotopic 
    fractionation of oxygen dissolved in freshwater and seawater in equilibrium with 
    the atmosphere.  Linnol. Oceanogr., 29(3), 620-632.
Billant, A., 1985.  Calibration des mesures d'une sonde CTD-O2 Neil-Brown.  Rapport 
    Scientifque et Technique de l'IFREMER, n1.
Billant, A., 1990.  Evaluation des thermomtres et pressiomtres SIS.  Rapport 
    interne de l'IFREMER, DRO-90.01/EO/BREST.
Groupe CITHER 1, 1994.  Campagne CITHER 1.  N/O L'Atalante (2 janvier - 19 mars 
    1993).  Recueil de donnes.  Volume 2: CTD-O2.  Rapport Interne LPO 94-04.
Groupe CITHER 2, 1995.  Campagne CITHER 2.  N/O Maurice Ewing (4 janvier - 21 mars 
    1994).  Recueil de donnes.  Volume 2: CTD-O2.  Rapport Interne LPO 95-04.
Millard, R.C., 1982.  CTD calibration and data processing techniques at WHOI using 
    the 1978 practical salinity scale.  International STD Conference and Workshop, 
    San Diego (8-11 February 1982).
South Atlantic Ventilation Experiment (SAVE).  Chemical, Physical and CTD Data 
    Report.  Scripps Institution of Oceanography, SIO Reference 92-2 and 92-10.  
    April 1992.
UNESCO, 1981.  Background papers and supporting data on the Practical Salinity 
    Scale, 1978.  UNESCO Technical Papers in Marine Science, n37, 144 p.
WOCE Operations Manual - Volume 3: The Observational Programme Section 3.1 WOCE 
    Hydrographic Programme - Part 3.1.3: WHP Operations and Methods.  WOCE Report 
    n68/91 - July 1991.

                                                                            A13/A14 CTD, CITHER-3

IV  LISTINGS ET FIGURES DES PARAMETRES 'BATHYSONDE'
    (VOIR L'ETAT)

Remarque: 1/Les mesures d'oxygne dissous ont t lisses verticalement sur 11 
          dbar pour liminer l'effet de la houle.

          2/Les mesures de salinit et d'oxygne dissous dduites des analyses 
          des chantillons d'eau de mer seront trouves dans le volume 3 du 
          recueil de donnes CITHER 3.


FIGURES (shown in PDF file)

FIGURE III-1:  Position gographique des 242 stations de la campagne CITHER 3.

FIGURE III-2:  Coupes synoptiques indiquant le niveau des prlvements  chaque 
               station de la campagne CITHER 3.

FIGURE III-3:  Ecarts de salinit entre deux bouteilles fermes au mme niveau:
                a) en fonction du numro de station  laquelle a t ralis le doublet,
                b) en fonction de la pression  laquelle a t ralis le doublet.

FIGURE III-4:  Histogramme des carts de salinit:
                a) pour les 308 doublets de la campagne,
                b) pour les 246 doublets raliss  pression suprieure  980 dbars.

FIGURE III-5:  Ecarts en oxygne entre deux bouteilles fermes au mme niveau:
                a) en fonction du numro de station  laquelle a t ralis le doublet,
                b) en fonction de la pression  laquelle a t ralis le doublet.

FIGURE III-6:  Histogramme des carts en oxygne:
                a) pour les 331 doublets de la campagne,
                b) pour les 261 doublets raliss  pression suprieure  980 dbars.

FIGURE III-7:  Rpartition des carts, tous les 400 dbars, entre la pression de 
               rfrence et la pression indique par le capteur Neil-Brown (sonde 
               2782) lors de l'talonnage pr- et post- campagne  la temprature de 20C:
                a) cycles monte en pression (profil descente),
                b) cycles descente en pression (profil monte).
                   La courbe de degr 3 qui rduit ces carts est reprsente.

FIGURE III-8:  Ecarts, tous les 400 dbars, entre  la pression de rfrence et la 
               pression indique par le capteur Neil-Brown (sonde 2782) aprs 
               correction de la linarit du capteur  20 (figure III-7), de 
               l'influence de temprature statique et de l'effet dynamique de temprature.
                a) monte en pression (profil descente),
                b) descente en pression (profil monte).
                   La courbe de degr 5 qui corrige la pression sur les profiles est 
                   reprsente.

FIGURE III-9:  Ecarts, en mtres,  chaque station, entre la longueur de cble fil 
               et l'immersion du capteur de pression Neil-Brown (aprs corrections) en 
               fin de profil descente.  Quelle que soit la profondeur, lorsque le 
               cble est rigoureusement vertical, les deux valeurs sont gales.

FIGURE III-10: Ecarts entre la temprature de rfrence et la temprature indique 
               par le capteur Neil-Brown lors de l'talonnage pr- et post- campagne.
               La courbe de degr 2 qui corrige la temprature sur les profils est 
               reprsente.

FIGURE III-11: Ecarts obtenus,  chaque station, entre la lecture des 3 
               thermomtres SIS, et la temprature indique par la sonde Neil-Brown: 
               la tempramentale est infrieure  3C.  Pendant  la dure de 
               fonctionnement, les carts restent constants  chaque niveau 
               d'observation.

FIGURE III-12: Ecarts entre la conductivit des chantillons et la conductivit 
              'bathysonde', au niveau du prlvement:
                a) en fonction du numro de la station concerne,
                b) en fonction de la pression au niveau du prlvement.
                   Ces carts sont le rsultat d'une calibration effectue sur l'ensemble 
                  des chantillons de la campagne.

FIGURE III-13: Ecarts entre la conductivit des 6187 chantillons valids et la 
               conductivit 'bathysonde', au niveau du prlvement, aprs recalage par 
               station ou groupe de stations:
                a) en fonction du numro de la station concerne,
                b) en fonction de la pression au niveau du prlvement.

                                                                            A13/A14 CTD, CITHER-3


FIGURE III-14: Histogrammes des carts entre la conductivit des chantillons et la 
               conductivit 'bathysonde', au niveau du prlvement, aprs recalage:
                a) pour la totalit des 6187 chantillons valids sur la campagne,
                b) pour les 4132 chantillons valids et prlevs  pression suprieure 
                   980 dbars.

FIGURE III-15: Mme lgende que figure III-14 pour les carts en salinit.

FIGURE III-16: Comparaison de diagrammes theta-S tracs d'aprs les donnes de la 
               campagne CITHER 3 et CITHER 1.  Dans les deux cas, les stations ont t 
               ralises  la mme position gographique.

FIGURE III-17: Comparaison de diagrammes theta-S de la campagne CITHER 3 avec les 
               donnes des campagnes SAVE obtenues  une position gographique proche:
                a) station 44 de CITHER 3 et station 76 de SAVE 2 (profil CTD),
                b) station 75 de CITHER 3 et station 134 de SAVE 3 (profil CTD).

FIGURE III-18: Comparaison de diagrammes theta-S de la campagne CITHER 3 avec les 
               donnes des campagnes SAVE obtenues  une position gographique proche:
                a) station 89 de CITHER 3 et station 209 de SAVE 4 (profil CTD),
                b) station 149 de CITHER 3 et station 226 de SAVE 4 (profil CTD).

FIGURE III-19: Comparaison de diagrammes theta-S de la campagne CITHER 3 avec les 
               donnes d'autres campagnes obtenues  une position gographique proche:
                a) stations 197 et 198 de CITHER 3, station 66 de SAVE 2 et station 143 
                   de OCEANUS 133,
                b) stations 210 et 212 de CITHER 3, station 52 de SAVE 2 et station 16 
                   de CITHER 1.

FIGURE III-20: Ecarts entre la valeur d'oxygne mesure sur les chantillons et 
               celle du profil descente 'bathysonde'  la pression du prlvement:
                a) en fonction du numro de la station concerne,
                b) en fonction de la pression au niveau du prlvement.
                   Ces carts sont le resultat d'un calcul effectu sur l'ensemble des 
                   chantillons de la campagne.

FIGURE III-21: Ecarts entre la valeur d'oxygne mesure sur les 6290 chantillons 
               valids et celle du profil descente 'bathysonde'  la pression du 
               prlvement, aprs recalage par station ou groupe de stations:
                a) en fonction du numro de la station concerne,
                b) en fonction de la pression au niveau du prlvement.

                                                                            A13/A14 CTD, CITHER-3


FIGURE III-22: Histogramme des carts en oxygne (en ml/l) entre la valeur mesure 
               sur les chantillons valids et celle du profil descente 'bathysonde'  
               la pression du prlvement, aprs recalage:
                a) pour la totalit des 6290 chantillons valids sur la campagne,
                b) pour les 4644 chantillons valids et prlevs  pression 
                   supsrieure  980 dbars.

FIGURE III-23: Histogramme des carts en oxygne (en mol/kg) entre la valeur 
               mesure sur les chantillons valids et celle du profil descente 
               'bathysonde'  la pression du prlvement, aprs recalage:
                a) pour la totalit des 6290 chantillons valids sur la campagne,
                b) pour les 4644 chantillons valids et prlevs  pression 
                   supsrieure  980 dbars.

FIGURE III-24: Profils d'oxygne dissous obtenus aux stations 25 et 212 de CITHER 3.  
               Les valuers d'oxygne mesures sur les prlvements de ces 2 stations sont 
               indiques. Pour comparaison, les profils d'oxygne des stations 38, 39 et 
               16, ralises  une position gographique proche, au cours de la campagne 
               CITHER 1, sont portes sur ces figures.

FIGURE III-25: Profils d'oxygne dissous obtenus aux stations 44 et 75 de CITHER 3.  
               Les valeurs d'oxygne mesures sur les prlvements de ces 2 stations sont 
               indiques. Pour comparaison, les mesures d'oxygne 'rosette' extraites des 
               stations 209 et 226, ralises  une position gographique proche, au 
               cours des campagnes SAVE sont portes sur ces figures.

FIGURE III-26: Profils d'oxygne dissous obtenus aux stations 89 et 149 de CITHER 3.  
               Les valeurs d'oxygne mesures sur les prlvements de ces 2 stations sont 
               indiques. Pour comparaison, les mesures d'oxygne 'rosette' extraites des 
               stations 209 et 226, ralises  une position gographique proche, au 
               cours des campagnes SAVE sont portes sur ces figures.

FIGURE III-27: Profils d'oxygne dissous obtenus aux stations 197 et 210 de CITHER 3.  
               Les valeurs d'oxygne mesures sur les prlvements de ces 2 stations sont 
               indiques. Pour comparaison, les mesures d'oxygne 'rosette' extraites des 
               stations 66 et 52, ralises  une position gographique proche, au cours 
               des campagnes SAVE sont portes sur ces figures.



__________________________________________________________________________________________
__________________________________________________________________________________________

                                                                            A13/A14 Tracers, CITHER-3

TABLE DES MATIERES 



   I  LE GROUPE CITHER-3   
  IL  CONTRIBUTIONS  L'ACQUISITION DES DONNES GOCHIMIQUES ET A LA RDACTION   
      DE CE RAPPORT   
 III  MESURES DE SALINIT ET OXYGNE DISSOUS   
  IV  ANALYSE DES LMENTS NUTRITIFS SUR LA RADIALE 
      A13: SILICATES, PHOSPHATES, NITRATES, NITRITES   
   V  NUTRIENTS MEASUREMENTS. SECTION WOCE A14   
  VI  MESURES DE CHLOROFLUOROMTHANES F11 ET F12   
 VII  CARBON SYSTEM   
VIII  LISTINGS ET TRACES PAR STATION DES PARAMTRES CHIMIQUES ET GOCHIMIQUES   



I LE GROUPE CITHER-3

Le programme CITHER* est l'une des contributions Franaises du programme 
international WOCE (World Ocean Circulation Experiment). Son objectif est de 
raliser cinq radiales d'hydrologie/gochimie lgre du rseau WHP (WOCE 
Hydrographic Programme) dans l'Atlantique Sud, et d'en analyser les rsultats, 
indpendamment, puis en association avec les donnes recueillies par d'autres 
pays.

L'objet de la campagne CITHER-3 (figure I-1) tait de raliser les radiales 
A13 et A14 du WHP, deux lignes mridiennes dans le Bassin Atlantique Sud-Est, 
l'une  la longitude nominale 9W, l'autre le long du continent Africain  une 
distance du talus continental voisine de 600 km. Une radiale transverse 
reliant l'extrmit sud de A13 au talus continental au large de Cape Town a 
galement t ralise. Cette campagne, qui s'est droule sur le Navire 
Ocanographique L'ATALANTE, a bnfici d'une coopration troite entre 
plusieurs laboratoires. La coordination en a t assure par Michel Arhan 
(IFREMER/LPO), galement Chef de Mission de la deuxime partie de la campagne 
(ligne A13), Herl Mercier (CNRS/LPO) tant Chef de Mission de la premire 
partie (ligne A14). Les mesures des divers paramtres taient sous la 
responsabilit scientifique des chercheurs dont les noms sont indiqus dans le 
tableau I-1 ci-dessous.

TABLEAU I-1: Chercheurs du groupe CITHER-3 responsables des divers types de 
             mesures.
                                  | 1re partie (A14)                  | 2me partie (A13)
----------------------------------|------------------------------------|------------------------------------
Mesures d'hydrologie              | Herl Mercier        (CNRS/LPO)    | Michel Arhan     (IFREMER/LPO)
  (bathsonde et prlvements)     |                                    |
Analyses des sels nutritifs       | Xos Alvarez Salgado (IIM/Vigo)    | Pascal Morin     (LOC/UBO)
Analyses des chlorofluoromthanes | Laurent Mmery       (CNRS/LODYC)  | Laurent Mmery   (CNRS/LODYC)        
Prlvements Hlium 3/Tritium     | Wolfgang Roether     (Univ. Brme) | Wolfgang Roether (Univ. Brme)
CO2 total                         | Linda Bingler        (BPNL/Sequim) | Linda Bingler    (BPNL/Sequim)
pH, Alcalinit                    | Aida Fernndez Ros  (IIM/Vigo)    | Melchor Gonzalez (Univ. Las Palmas)


La campagne CITHER-3 a t finance par ELFREMER et le CNRS  travers le 
Programme National d'Etudes de la Dynamique du Climat (PNEDC). L'IIM/Vigo, 
l'Universit de Bretagne Occidentale, l'Universit de Brme, l'Universit de 
Las Palmas, et le BPNL/Sequim y ont galement contribu. Nous remercions le 
Commandant Gourmelon et l'quipage de l'ATALANTE pour leur concours prcieux 
au cours de cette campagne.

                                                                            A13/A14 Tracers, CITHER-3


II  CONTRIBUTIONS A L'ACQUISITION DES DONNES GOCHIMIQUES ET A LA RDACTION 
    DE CE RAPPORT

Ce troisime volume du recueil de donnes de CITHER-3 est consacr aux 
paramtres hydrologiques (salinit et oxygne) et aux traceurs gochimiques 
(sels nutritifs, chlorofluoromthanes, paramtres du systme carbonique) 
mesurs sur les prlvements  la rosette. Le premier volume contient une 
prsentation d'ensemble de la campagne et les rsultats des mesures  en route 
 des paramtres mtorologiques, de la bathymtrie, et du courant par 
courantomtrie Doppler de coque. Le deuxime volume prsente les mesures de la 
sonde CTD-O2.

Les noms et affiliations des scientifiques embarqus ayant contribu  
l'acquisition des donnes du volume 3 au cours de la campagne ou  leur 
traitement (calibration, validation)  terre  l'issue de la campagne, sont 
lists dans le tableau II-1 ci-dessous.


TABLEAU II-1

NOM                          | CONTRIBUTION        | LABORATOIRE          | A13 | A14
-----------------------------|---------------------|----------------------|-----|----
GOUILLOU, Jean-Pierre        | Electr. Rosette     | IFREMER/LPO          |  X  |
BAURAND, Franois            | Oxygne             | ORSTOM/Cayenne       |  X  |
LUX, Muriel                  | Salinit            | IFREMERALPO          |  X  |
BILLANT, Andr               | Salinit et Oxygne | IFREMER/LPO          |  X  |
AILVAREZ SALGADO, Xose Anton | Sels Nutritifs      | IIM/Vigo             |  X  |
PAZO FERNANDEZ, Maria Jose   | Sels Nutritifs      | IIM/Vigo             |     |  X
RIOS,  Aida                  | Alcalinit/pH       | IIM/Vigo             |     |  X
RELLAN, Trinidad             | Alcalinit/pH       | IIM/Vigo             |     |  X
MEMERY, Laurent              | Frons              | LODYC/CNRS           |     |  X
MESSIAS, Marie-Jos          | Frons              | LODYC/CNRS           |  X  |  X
LAIME, Ann                   | Frons              | LODYC/CNRS           |     |  X
GUILYARDI, Eric              | Frons              | CERFACS/Toulouse     |     |  X
WEYLAND, Joachim             | Helium              | Tritium  Univ. Brme |  X  |
BINGLER, Linda               | TCO2                | BPNL/Sequim          |  X  |  X
ARISTEGUI, Javier            | TCO2                | Univ. Las Palmas     |     |  X
DECK, Muriel                 | Oxygne             | LPO/CNRS             |  X  |
REYNAUD, Thierry             | Salinit            | UBO/LPO              |  X  |
BRANELLEC, Pierre            | Salinit et Oxygne | IFREMER/LPO          |  X  |
MORIN, Pascal                | Sels nutritifs      | LOC/UBO              |  X  |
WAFAR, Mohideen              | Sels nutritifs      | LOCIUBO              |  X  |
MASSON, Annick               | Sels nutritifs      | LOCIUBO              |  X  |
SARAGONI, Gilles             | Frons              | LODYC/CNRS           |  X  |
TAILLEUX, Rmi               | Frons              | LODYC/CNRS           |  X  |
GARRIC, Gilles               | Frons              | CERFACS/Toulouse     |  X  |
LAUE, Hendrick               | Helium              | Tritium  Univ. Breme |  X  |
GONZALEZ, Melchor            | TCO2                | Univ. Las Palmas     |  X  |


                                                                            A13/A14 Tracers, CITHER-3

Les significations des acronymes utiliss dans le tableau et dans le texte 
sont indiques cidessous:

CITHER:      CIrculation THERmohaline
ORSTOM:      Institut Franais de Recherche Scientifique pour le Dveloppement 
               en Coopration
IFREMER:     Institut Franais de Recherche pour l'Exploitation de la Mer
CNRS:        Centre National de la Recherche Scientifique
PNEDC:       Programme National d'Etude de la Dynamique du Climat
LPO:         Laboratoire de Physique des Ocans
LODYC:       Laboratoire d'Ocanographie Dynamique et de Climatologie
UBO:         Universit de Bretagne Occidentale
IIM/Vigo:    Instituto de Investigaciones Marinas/Vigo (Espagne)
BPNL/Sequim: Battelle Pacific Northwest Laboratories/Sequim (USA)

Des copies de ce rapport ainsi que des volumes 1 et 2 peuvent tre obtenues 
auprs de:

             Andr Billant
             Laboratoire de Physiques des Ocans
             IFREMER/Centre de Brest
             B.P. 70
             29280 Plouzan
             France
             e-mail: andre.Billant@ifremer.fr



III  Measures de Salinite et Oxygene Dissous 
     (Andr Billant et Pierre Branellec, IFREMER-Brest)

De manire gnrale,  chaque station, les 30 ou 32 bouteilles de la rosette 
de prlvement sont fermes au cours de la remonte de la sonde aprs arrt au 
niveau du prlvement. Ces niveaux sont choisis de manire  tre spares au 
maximum de 300 mtres. Dans la mesure du possible,  chaque station, deux 
bouteilles taient fermes  un ou plusieurs niveaux. La figure III-1 prsente 
une vue synoptique des niveaux prlevs pendant la campagne CITHER-3.


1   SALINITE

1.1 PRCAUTIONS DE PRLVEMENT

Us chantillons sont recueillis dans des flacons de 125 ml dont ltanchit 
est assure par un joint de caoutchouc. Trois rinages des flacons sont 
effectus. Des que toutes les bouteilles de la station sont prleves, le col 
des flacons est rinc  l'eau douce pour viter la formation de cristaux de 
sel sur l'extrieur du joint aprs vaporation pendant la dure du stockage. 
Les chantillons sont entreposes dans le conteneur-laboratoire dont la 
temprature est contrle et fixe  20  1C puis analyses dans un dlai de 
20  30 heures aprs leur prlvement.

                                                                            A13/A14 Tracers, CITHER-3

1.2 ANALYSE DES CHANTILLONS

La salinit des chantillons est dtermine d'aprs l'quation PSS 78 (UNESCO, 
1981). Le salinomtre, de type Guildline, est standardis comparativement  
des ampoules d'eau normale du lot P125 (K15=0.99982) fabriques  Wormley le 
ler aot 1994. Les 7007 chantillons de la campagne ont t analyss par un 
salinomtre PORTASAL. La temprature du bain thermostat est fixe  une 
temprature suprieure  celle du laboratoire afin d'avoir les meilleures 
conditions pour l'analyse des chantillons. Cette temprature tait fixe  
21C pendant toute la dure de la campagne. Le salinomtre est quip &une 
pompe pristatique pour acclrer le passage de l'eau des chantillons dans la 
cellule de mesure.

1.2.1  MODE OPRATOIRE POUR LA STANDARDISATION DU SALINOMTRE

Initialement le salinomtre est standardis en utilisant au moins deux 
ampoules d'eau normale. Ensuite, tous les jours, avant de commencer la srie 
d'analyses, la standardisation est vrifie puis ajuste si la valeur de la 
salinit de l'ampoule d'eau standard affiche, s'carte de plus de 0.0010 de 
celle de la veille. Deux ampoules, au moins, sont utilises dans le cas ou il 
est ncessaire de refaire la standardisation.

Au cours de la journe, aprs l'analyse des chantillons de chaque station, la 
stabilit du salinomtre est contrle en vrifiant la standardisation avec 
une nouvelle ampoule d'eau normale. La nouvelle valeur lue est note sur la 
fiche d'analyse de la station. En cas de drive du salinomtre, les valeurs de 
salinit notes lors de l'analyse des chantillons sont corriges en admettant 
une drive linaire.

1.2.2 MODE OPRATOIRE POUR L'ANALYSE DES CHANTILLONS

L'opration de remplissage de la cellule de mesure du salinomtre avec l'eau 
de l'chantillon, puis vidage, est rpte trois fois avant de faire une 
premire lecture. Aprs une nouvelle vacuation et remplissage de la cellule, 
une deuxime lecture est effectue. Si l'cart de salinit entre ces deux 
lectures est suprieur  0.0003, une troisime lecture est ncessaire.

La mesure retenue est la moyenne de ces deux ou trois lectures.

Aprs l'analyse de tous les chantillons de la station et contrle de la 
stabilit du salinomtre, cette mesure est corrige de la drive si ncessaire 
pour donner la salinit de l'chantillon.

1.2.3 DROULEMENT DES SRIES D'ANALYSE PENDANT LA CAMPAGNE

Le mme salinomtre PORTASAL a t utilis pendant toute la campagne. La 
stabilit a t remarquable: il a t rarement ncessaire &ajuster la 
standardisation. La drive maximum observe aprs une journe d'analyses tait 
de 0.0009 en salinit. Le plus souvent, le contrle de standardisation du 
matin montrait que l'appareil avait retrouv son niveau de la veille avant la 
srie d'analyses journalires.

                                                                            A13/A14 Tracers, CITHER-3

1.3 RPTABILITE DES MESURES

La rptabilit des prlvements et analyses a t verifie a trois stations 
en cours de campagne en fermant un grand nombre de bouteilles au mme niveau. 
Les mesures de salinit faites sur les chantillons prlevs dans chacune des 
bouteilles donnent les rsultats suivants:

   STATION                            |    45     |    160    |    211
   -----------------------------------|-----------|-----------|----------
   Niveau de fermeture des bouteilles | 3000      | 3200      | 3000
   Nombre de bouteilles               |   30      |   16      |   15
   Valeur moyenne de la salinit      |   34.8898 |   34.8695 |   34.9087
   Ecart maximum  la moyenne         |    0.004  |    0.004  |    0.004
   Ecart-type                         |    0.0015 |    0.0016 |    0.0015

On peut en dduire que la rptabilit, des mesures de salinit est 
systmatiquement infrieure  0.002.

Des doublets ont t raliss pendant toute la campagne en fermant deux 
bouteilles au mme niveau. Les carts obtenus  chacun de ces doublets sont 
prsents sur la figure III-2, ils ont t ralises  une grande majorit de 
stations et  tous les niveaux de prlvement entre le fond et la surface: 
l'cart maximum observ est de 0.0090. La figure III-3 reprsente 
l'histogramme des carts pour les 308 doublets considrs. Le pourcentage par 
classe est identique en considrant, d'une part, la totalit des doublets et, 
d'autre part, ceux ralises  une pression suprieure  980 dbars: 52% des 
carts sont infrieurs  0.0010 et 88% infrieurs  0.0030. L'cart-type 
obtenu pour ces 308 doublets est de 0.00199 (il est de 0.00192 pour ceux 
prlevs  pression suprieure  980 dbars).



2   OXYGENE DISSOUS

2.1 TECHNIGUE D'CHANTILLONNAGE

Les chantillons sont recueillis dans des flacons  bouchon plongeur de 120 
ml. Aprs remplissage du flacon, une prise de temprature est effectue avant 
de laisser dborder 3 fois l'quivalent de volume.

Aprs addition successive de 1 ml de chaque ractif de fixation, puis 
bouchage, l'agitation est pratique pendant 30 secondes. Lorsque toutes les 
bouteilles ont t prleves, les flacons sont retourns un  un pour remise 
en suspension du prcipit, puis entreposs dans le conteneur laboratoire a la 
temprature de 20  1C. Les analyses sont effectues dans un dlai de 4  24 
heures.

                                                                            A13/A14 Tracers, CITHER-3

2.2 ANALYSE DES CHANTILLONS

2.2.1  MODE OPRATOIRE

Les conditions opratoires et la mthode d'analyse mise au point au L.P.O. 
(Laboratoire de Physique des Ocans) sont conformes aux recommandations WOCE 
(Operations Manual, 1991).

Les 7033 chantillons prlevs pendant la campagne ont t analyss dans le 
conteneurlaboratoire dont la temprature est contrle et fixe  20  1C.

La totalit de l'chantillon est acidifie dans le flacon de prlvement et 
l'iode libr est dos par une solution de thiosulfate de sodium dont la 
normalit est de l'ordre de 0.02 N. Une burette a piston dlivre le 
thiosulfate. Elle est pilote par un titroprocesseur Methrorn associ  une 
lectrode de platine qui contrle le potentiel de la raction chimique. La 
vitesse d'injection du thiosulfate est maximale jusqu' dtection du dbut de 
saut de potentiel, puis ralentie et se fait par pas de 0.002 cm3 autour de 
l'quivalence. La stabilisation du potentiel, aprs dpassement de 
l'quivalence, provoque l'arrt d'injection du thiosulfate et le 
titroprocesseur dtermine automatiquement le point d'inflexion sur la courbe 
de potentiel et le volume de thiosulfate associ. La valeur d'oxygne est 
calcule, et automatiquement imprime,  partir des informations mmorises 
dans le titroprocesseur et du volume du flacon introduit avant de dmarrer le 
dosage.

La mthode de dosage prsente une trs bonne rptabilit des rsultats car 
entirement automatise. La qualit des mesures en valeur absolue est 
nanmoins aussi dpendante des prcautions dans le prlvement des 
chantillons que des vrifications de volumtrie et de concentration des 
ractifs. Le paragraphe suivant prcise les contrles et vrifications qui ont 
entour les mesures d'oxygne effectues lors de la campagne.

2.2.2 PRCAUTIONS PARTICULIRES

2.2.2.1 VOLUMTRIE
La verrerie utilise (flacons de prlvement, dispensettes pour les ractifs, 
pipette automatique, ... .) est calibre suivant le principe de la double 
pese et les indications de la balance vrifies puis corriges par 
comparaison avec deux sries de poids talons. Toutes les corrections 
recommandes par WOCE (temprature, pousse de l'air, ... .). ont t 
appliques aux peses.

 1  Le volume des flacons de prlvements est dtermin   0.003 cm3 en 
    rptant trois fois l'opration de double pese. Le volume moyen des 
    flacons utiliss est de 120  2 cm3.
 2  Le volume des 2 dispensettes (introduction des ractifs de fixation dans 
    les prlvements) est dtermin  1.000  0.003 cm3 et 0.997  0.003 cm3.
 3  Le volume de la pipette automatique (prise d'essai d'iodate de potassium 
    pour dtermination de la normalit du thiosulfate de sodium) est: 5.0087  
    0.0004 cm3.
 4  L'indication de volume de la burette  piston qui dlivre le thiosulfate de 
    sodium pour le dosage a t vrifie en 3 points dans la gamme utile 
    comprise entre 2 et 8 cm3.  L'indication de la burette sous-estime le 
    volume rel de 0.004  0.0005 cm3. La rsolution de l'affichage tant de 
    0.00 1 cm3, la correction de volume de thiosulfate est prise en compte dans 
    les calculs.

                                                                            A13/A14 Tracers, CITHER-3

2.2.2.2 CONCENTRATION DES RACTIFS
   La concentration des ractifs de fixation de l'oxygne est celle indique 
    par Carpenter (1965). Ils sont prpars avec des produits de puret garantie 
    "pour analyse".
   La solution d'iodate de potassium qui sert de rfrence pour les mesures est 
    prpare  partir d'une pese de cristaux dont le degr de puret (99.983%) 
    est garanti par un certificat d'analyse du fournisseur. La dissolution de 
    3.56768g de KI03 dans une fiole jauge de 5000 cm3 fournit la solution 
    rfrence de la campagne CITHER-3: sa normalit est de 0.020002  0.000005 
    N. L'incertitude admise dans la valeur de la normalit provient, d'une part, 
    de la correction de pese (dcalage de 0.02 mg d'aprs les poids talons) 
    et, d'autre part, de l'incertitude sur le volume de la fiole jauge indique 
    par le fournisseur (1.2 cm3). Cette solution rfrence, divise en 5 
    parties, est conserve en flacons tanches en attente d'utilisation pendant 
    la campagne.

2.2.2.3. CONTRLES DES RACTIFS PENDANT LA CAMPAGNE
 a) Dtermination du blanc d'analyse
    Quotidiennement, avant la srie d'analyses des chantillons et  chaque 
    changement de ractifs, trois dosages successifs permettent de dterminer 
    le blanc des ractifs en mlangeant 1 cm3 de chacun des trois ractifs  
    100 cm3 d'eau distille. La valeur moyenne du blanc est de 0.017 ml pendant 
    la premire partie de la campagne et de 0.019 ml pendant la seconde partie: 
    il a t tenu compte de la "valeur journalire" dans le calcul du taux 
    d'oxygne.

 b) Dtermination de la normalit du thiosulfate
    Deux solutions de 25 litres de thiosulfate ont t prpares au dbut de 
    chacune des deux parties de la campagne: la prparation donne une normalit 
    de l'ordre de 0.02 N. Un litre de cette solution mre est extrait 
    quotidiennement pour les analyses du jour. La normalit du thiosulfate est 
    obtenue par dosage de cinq prises d'essai (5.0087 cm3) d'iodate de 
    potassium rfrence. La moyenne de ces cinq dosages permet de dterminer la 
    "valeur journalire" de la normalit si l'cart-type est juge acceptable. 
    Dans le cas contraire, une nouvelle srie est effectue. Le suivi quotidien 
    de l'volution de la normalit du thiosulfate permet de dtecter toute 
    anomalie et de procder  toutes les vrifications avant d'admettre cette 
    valeur comme applicable aux analyses du jour.

Le contrle journalier a permis de constater que la normalit a varie entre 
0.020010 N et 0.019938 N pour la premire prparation puis entre 0.020044 et 
0.019910 N pour la seconde. Ceci indique que la normalit du thiosulfate a 
volu en 34 jours de 0.36% de sa valeur pendant la premire partie de la 
campagne et de 0.66% en 30 jours au cours de la seconde partie.
                                                                            A13/A14 Tracers, CITHER-3

2.2.3 DTERMINATION DU TAUX D'OXYGNE DANS LES CHANTILLONS

Les dosages sont effectus  la temprature de 20C ce qui permet de 
s'affranchir de la correction de temprature sur la volumtrie des ractifs 
iodate et thiosulfate. La totalit du volume prlev tant dose directement 
dans le flacon, la concentration d'oxygne est obtenue en utilisant la formule 
recommande dans le document WOCE Operations Manual (1991).

                   (Vx - Vblk,dw)  VIO3  NIO3  5598
                   -----------------------------------  -1000  DOreg
                             (Vstd - Vblk,dw)  
       02 (ml/l) =   ------------------------------------------------
                                      (Vbot - Vreg)

avec:     
     Vx = volume de thiosulfate pour dosage de l'chantillon (cm3)
Vblk,dw = volume de thiosulfate pour le blanc avec eau distille (cm3)
   Vstd = volume de thiosulfate pour dtermination de la normalit (cm3)
   Vbot = volume du flacon de prlvement (cm3)
   Vreg = volume des ractifs introduits dans l'chantillon (cm3)
   VIO3 = volume de la prise d'essai d'iodate rfrence (cm3)
   NIO3 = normalit de l'iodate
  DOreg = 0.0017

Dans le cas de CITHER-3, nous avons les valeurs suivantes

Vblk,dw = "valeur journalire"
   Vstd = "valeur journalire"
   Vreg = 2.000
   VIO3 = 5.0087
   NIO3 = 0.020002


2.3 UNITS D'EXPRESSION DE L'OXYGNE

Le rsultat des analyses est exprime en millilitres par litre (ml/l): tous les 
contrles sont effectus dans cette unit.

La temprature des chantillons tant prise au prlvement, la densit au 
moment de la fixation de l'oxygne est connue. Un calcul a permis de 
transformer toutes les valeurs pour les passer dans l'unit micromoles par 
kilogramme (mol/kg) en utilisant la formule

                                   44.660 x 02 (ml/l)
                    02(mol/kg) =  ------------------
                                        rho-sw

dans laquelle rho-sw = densit de l'chantillon  la temprature du 
prlvement (Millero and Poisson, 1981).
                                                                            A13/A14 Tracers, CITHER-3

2.4 RPTABILIT DES MESURES

La rptabilit des prlvements et analyses a t vrifie au cours de la 
campagne,  trois stations "test", en fermant plusieurs bouteilles au mme 
niveau. Les rsultats obtenus  ces trois stations sont regroupes dans le 
tableau suivant:

   STATION                            |    45     |    160    |    211
   -----------------------------------|-----------|-----------|----------
   Niveau de fermeture des bouteilles | 3000      | 3200      | 3000
   Nombre de bouteilles               |   30      |   16      |   15
   Valeur moyenne d'oxygne           |   5.518   |    5.354  |    5.430
   Ecart maximum  la moyenne         |    0.008  |    0.014  |    0.015
   Ecart-type                         |    0.004  |    0.006  |    0.00711

Ces rsultats permettent de considrer que les mesures de la campagne sont 
reproductibles  0.010 ml/l prs.

La figure III-4 montre les carts obtenus sur les deux bouteilles fermes au 
mme niveau: ces niveaux taient rpartis entre le fond et la surface et 
chantillonnaient toute la gamme de mesure: l'cart maximum observ est de 
0.08 ml/l. La figure III-5 prsente les histogrammes d'carts obtenus pour les 
331 doublets considrs.

Pour l'ensemble des 331 doublets, 52% des carts sont infrieurs  0.005 ml/l 
et 86% sont infrieurs  0.015 ml/l: l'cart-type est de 0.014 ml/l. En ne 
considrant que les  doublets effectues a une pression suprieure  980 dbar, 
le pourcentage dans chaque classe est amlior: 56% sont infrieurs  0.005 
ml/l et 90% infrieurs  0.015 MIA. Pour ceux-ci l'cart-type est de 0.012 
ml/l.



2.5 CONTRLE DE LA NORMALIT DE LA SOLUTION KLO3 RFRENCE

Avant la campagne CITHER-3, une intercomparaison a t effectue au 
Laboratoire entre les trois prparations d'iodate de potassium utilises comme 
rfrence  chacune des trois campagnes CITHER. La valeur de normalit, 
obtenue par pese des cristaux, et adopte pour chacune des prparations, 
tait:

           1. prparation CITHER-1: normalit = 0.020001
           2. prparation CITHER-2: normalit = 0.019993
           3. prparation CITHER-3: normalit = 0.020002

Une solution de thiosulfate est dose successivement par une srie de 10 
prises d'essai sur chacune de ces solutions d'iodate. Les conditions 
opratoires sont les mmes que celles appliques en mer pendant les campagnes. 
De cette manire, la srie de 10 dosages permet de dduire une valeur moyenne 
pour la normalit du thiosulfate:

      prparation CITHER-1: normalit du thiosulfate = 0.019761
      prparation CITHER-2: normalit du thiosulfate = 0.019795
      prparation CITHER-3: normalit du thiosulfate = 0.019792

En admettant que les prparations de CITHER-1 et CITHER-2 sont restes stables 
et que donc leur normalit n'a pas volue dans le temps, ce qui est 
probablement le cas, on constate une erreur de 0.15% entre la rfrence de 
CITHER-1 et celle de CITHER-3.

Cette erreur conduit  une diffrence maximale de 0.008 ml/l dans la 
dtermination du taux d'oxygne dissous sur les chantillons  un niveau de 
5.8 ml/l.
                                                                            A13/A14 Tracers, CITHER-3

3  DES RESULTATS 

La figure III-6 prsente la carte avec la position gographique des stations 
effectues pendant la campagne CITHER-3. Quelques stations extraites des 
campagnes CITHER-1 et SAVE y sont indiques afin de comparer les rsultats 
obtenus  des positions gographiques proches. Ces stations de comparaison 
sont choisies dans des zones gographiques rparties le long des deux radiales 
de la campagne dans des masses d'eau dont les caractristiques ne sont pas 
ncessairement conservatives.

3.1  MESURES DE SALINIT

Les mesures de salinit sont compares  l'aide des diagrammes theta-S des couches 
&eau profonde dont la temprature potentielle est dduite de la temprature 
mesure par la sonde CTD 02 au niveau des prlvements.

Des exemples sont prsents sur les figures III-7  III-10: il s'agit de 
diagrammes, aux allures diffrentes, dans une gamme de salinit comprise entre 
34.71 et 34.96. On observe que, dans chaque cas, la superposition des 
diagrammes est tout  fait satisfaisante et ne montre pas de dcalage 
systmatique entre les sries de mesures. Il en rsulte que les valeurs de 
salinit de la campagne CITHER-3 sont d'une qualit comparable  celles de la 
campagne CITHER-1 effectues par notre Laboratoire et a celles des campagnes 
SAVE organises par un autre Laboratoire (Scripps Institution of 
Oceanography).

3.2  MESURES D'OXYGNE DISSOUS

Les mesures d'oxygne de la campagne CITHER-3 sont compares aux mesures de 
CITHER-1 (figure III-11) et  celles de SAVE (figures III-12  III-14) aux 
mmes stations que pour le contrle de la salinit.

La figure III-11 met en vidence un dcalage de l'ordre de 0.1 ml/l entre les 
valeurs de CITHER-1 et celles de CITHER-3 dans les deux cas considrs. Ce 
dcalage ne peut tre attribue  des erreurs analytiques (estimes au maximum 
 0.0087 MIA au paragraphe 2.5) mais plutt  la variabilit de l'oxygne dans 
le bassin quatorial. En effet, dans ce bassin, les mesures de CITHER-1 
mettaient en vidence une variabilit est-ouest de 0.6 ml/l et nord-sud de 
0.20 ml/l sur une distance de 360 milles. Les mesures de CITHER-3 confirment 
une variabilit nord-sud de 0.20 ml/l. Il n'est donc pas surprenant d'observer 
un dcalage de l'ordre de 0.1 ml/l,  la mme position gographique, entre 
deux campagnes spares dans le temps par deux annes.

Us figures III-12  III-14, montrent que, dans d'autres zones gographiques, 
les mesures d'oxygne de CITHER-3 sont proches de celles de SAVE. Il faut 
rappeler que les mesures de CITHER-1 compares  celles de SAVE montraient 
galement un trs bon accord entre les deux sries.

Ces comparaisons prouvent que les valeurs & oxygne obtenues au cours des 
diffrentes campagnes CITHER et SAVE sont de qualit comparables et 
fournissent des ensembles de donnes homognes: les carts observs 
correspondent  des modifications de la masse d'eau.

                                                                            A13/A14 Tracers, CITHER-3

4  REFERENCES 

Carpenter, J.H., 1965. The Chesapeake Bay Institute technique for the Winkler 
    dissolved oxygen method. Limnol. Oceanogr., 10, 141-143.

Le Groupe CITHER-1, 1994. Campagne CITHER-1 (2 janvier - 19 mars 1993). 
    Recueil de donnes, volume 3/4, documents scientifiques du Centre ORSTOM 
    de Cayenne, O.P. 15, pp. 7-30.

Le Groupe CITHER-2, 1996. Campagne CITHER-2 (4 janvier - 21 mars 1994). 
    Recueil de donnes, volume 3, Rapport Interne L.P.O. 96-02, pp. 5-27.

Millero, F.J., and A. Poisson, 1981. "International one-atmosphere equation of 
    state of Sea Water." Deep Sea Res., 28, 625-629.

UNESCO, 1981. Background papers and supporting data on the Practical Salinity 
    Scale, 1978. UNESCO Technical Papers in Marine Science, n 37, 144.

WOCE Operations Manual, 1991. Volume 3: The Observational Program Section 3.1 
    WOCE Hydrographic Program Part 3.1.3: WHP Operations and Methods. WOCE 
    Report No. 68/91. July 1991.


FIGURE LEGENDS (see pdf doc for figures)

CAMPAGNE CITHER-3 - Janvier/Mars 1995
               
               
Figure I-1:    Carte des stations d'hydrologie/gochimie, lgre ralises 
               pendant la campagne CITHER-3.
               
               
Figure III-1:  Coupes synoptiques indiquant le niveau des prlvements  chaque 
               station de la campagne CITHER-3.
               
               
Figure III-2:  Ecarts de salinit entre deux bouteilles fermes au mme niveau: 
               a) en fonction du numro de station  laquelle est ralis le 
                  doublet, 
               b) en fonction de la pression  laquelle est ralis le doublet.
               
               
Figure III-3:  Histogramme de salinit entre deux bouteilles fermes au mme 
               niveau: 
               a) pour l'ensemble des 308 doublets de la campagne,
               b) pour les 246 doublets raliss  pression suprieure  980 dbars.
               
               
Figure III-4:  Ecarts en oxygne entre deux bouteilles fermes au mme niveau: 
               a) en fonction du numro de station  laquelle est ralis le 
                  doublet, 
               b) en fonction de la pression  laquelle est ralis le doublet.
               
               
Figure III-5:  Histogramme des carts en oxygne entre deux bouteilles fermes 
               au mme niveau 
               a) pour les 331 doublets de la campagne, 
               b) pour les 261 doublets raliss  pression suprieure  980 dbars.
               
               
Figure III-6:  Position gographique des 242 stations de la campagne CITHER-3. 
               La position des stations CITHER-1 et SAVE utilises pour 
               comparaison est indique.
               
               
Figure III-7:  Comparaison des diagrammes theta-S  deux stations de CITHER-3 avec 
               ceux obtenus  CITHER-1  la mme position gographique.
               
               
Figure III-8:  Comparaison des diagrammes theta-S  deux stations de CITHER-3 avec 
               ceux obtenus  SAVE  la mme position gographique.
               
               
Figure III-9:  Comparaison des diagrammes theta-S  deux stations de CITHER-3 avec 
               ceux obtenus  SAVE  la mme position gographique.
               
               
Figure III-10: Comparaison des diagrammes theta-S  des stations de CITHER-3 avec 
               ceux obtenus  SAVE et CITHER-1  des positions gographiques 
               proches.
               
               
Figure III-11: Comparaison des mesures d'oxygne dissous obtenues  deux 
               stations de CITHER-3 avec celles de CITHER-1  la mme position 
               gographique.
               
               
Figure III-12: Comparaison des mesures d'oxygne dissous obtenues  deux 
               stations de CITHER-3 avec celles de SAVE  la mme position 
               gographique.
               
               
Figure III-13: Comparaison des mesures d'oxygne dissous obtenues  deux 
               stations de CITHER-3 avec celles de SAVE  la mme position 
               gographique.
               
               
Figure III-14: Comparaison des mesures d'oxygne dissous obtenues  deux 
               stations de CITHER-3 avec celles de SAVE  la mme position 
               gographique.

                                                                            A13/A14 Tracers, CITHER-3

IV  ANALYSE DES LMENTS NUTRITIFS SUR LA RADIALE A13:
    SILICATES, PHOSPHATES, NITRATES, NITRITES 
    (Pascal Morin et Mohideen Wafar)
    Laboratoire d'Ocanographie Chimique, Universit de Bretagne Occidentale 
      et UPR CNRS 9042 Roscoff.

PARTICIPANTS:
Les ANALYSES d'lments nutritifs (silicates, phosphates, nitrates, nitrites) 
sur la radiale A13 durant la campagne CITHER-3 ont t ralises par l'quipe 
du Laboratoire d'Ocanographie Chimique (Annick Masson, Pascal Morin et 
Mohideen Wafar).


1. QUIPEMENT ET TECHNIQUES D'ANALYSE:

Les mesures des quatre sels nutritifs ont t ralises simultanment sur deux 
chanes double-voies d'analyse en flux continu de type AutoAnalyser II 
Technicon (Bran et Luebbe) suivant les procdures analytiques standards 
dcrites dans le Manuel d'Analyse de Trguer et Le Corre (1975):

SILICATES Si(OH)4
Le silicium minral est dissous dans l'eau de mer essentiellement (95%) sous 
forme de molcules d'acide orthosilicique Si(OH)4 (5% se trouve sous forme 
ionise SiO(OH)3-). Dans la zone euphotique, il est consomm par le 
phytoplancton (essentiellement les diatomes) et peut tre un important 
facteur limitant de sa croissance. Sa rgnration dans l'eau de mer provient 
de la dgradation du silicium organique particulaire mais galement de la 
dissolution des sels minraux, tels que les alumino-silicates, dans les zones 
ctires ou proches du fond. Par analogie avec les autres sels nutritifs 
(nitrates, phosphates), le terme de "silicates" dissous continue  tre 
utilis improprement.

La mthode qui sert de rfrence est celle de Mullin & Riley (1955), modifie 
par Fanning & Pilson (1973). Les "silicates" dissous dans l'eau de mer sous 
forme d'acide orthosilicique monomre ou dimre ragissent en milieu acide (1 
< pH < 2) avec les ions molybdates pour former un htropolyacide, l'acide 
silicomolybdique. Ce complexe jaune est rduit par un mlange de "mtol" 
(sulfate de mthyl-amino-4-phnol) et de sulfite de sodium pour former un 
"bleu de molybdne". L'interfrence avec les phospho- et arsniomolybdates est 
vite en oprant  pH convenable et en ajoutant de l'acide oxalique. La 
raction est acclre en chauffant le complexe dans un bain marie  37C. La 
densit optique du complexe form est mesure  660 nm dans des cuves de 5 
cm3. Pour les chantillons les plus concentrs en silicates dont les 
concentrations sont suprieures  60 mol/kg-1 (les concentrations dpassent 
110 mol/kg-1 dans le bassin du Cap), une dilution des chantillons a t 
effectue en insrant dans le manifold un circuit de dilution de l'chantillon 
avec de l'eau dionise. Selon cette procdure, la loi de Beer-Lambert est 
vrifie jusqu' 140 mol/kg-1. La limite de dtection est de 0. 1 mol/kg-1.


                                                                            A13/A14 Tracers, CITHER-3

PHOSPHATES P04 3-
Le phosphore minral dissous dans l'eau de mer est essentiellement prsent 
sous forme d'ions orthophosphates (surtout sous forme HP042- et P0443-). La 
mthode utilise pour le dosage des orthophosphates a t mise au point par 
Murphy & Riley (1962). Les ions orthophosphates sont susceptibles de ragir 
avec le molybdate d'ammonium en milieu acide pour former un complexe jaune, le 
phosphomolybdate d'ammonium. Par rduction de ce complexe, on obtient une 
coloration bleue. L'utilisation de l'acide ascorbique comme agent rducteur 
donne les rsultats les plus reproductibles et il a l'avantage de pouvoir tre 
utilis dans un ractif unique: molybdate d'ammonium, acide ascorbique, acide 
sulfurique et antimonyl tartrate de potassium. L'antimoine fourni par 
Fantimonyl rduit le temps de dveloppement de la coloration de 24 heures  
quelques minutes. L'utilisation d'un bain marie  37C acclre le 
dveloppement de la coloration. L'intensit de la coloration est mesure  880 
nm. La mthode permet de mesurer les concentrations en phosphates dans la 
gamme des concentrations prsentes dans l'eau de mer (entre 0 et 3 mol/kg-1) 
et la limite de dtection est de 0.02 mol/kg-1 (elle correspond  une 
absorbance de 0.005 en cuves de 10 cm3 de trajet optique).

NITRATES NO3- et NITRITES N02-
Lors du dosage, les nitrates dissous dans l'eau de mer sont rduits presque 
totalement (> 95%) en nitrites par passage sur une colonne de cadmium trait au 
cuivre (Wood et al, 1967). La colonne rductrice a t prpare en utilisant du 
cadmium en grains tamiss entre entre 0,25 et 0,315 mm. La mthode a t 
lgrement modifie par rapport  la mthode d'origine: le chlorure d'ammonium 
ajust  pH = 8.5 est utilis au lieu de FEDTA (Grasshof, 1964) conformment 
aux meilleurs rsultats de rduction obtenus (Strickland et Parsons, 1972). Les 
nitrites sont ensuite doss selon la mthode base sur la raction de Griess 
applique  l'eau de mer par Bendschneider & Robinson (1952). Us nitrites 
forment un diazoque avec la sulfanilamide en milieu acide (pH < 2). Le 
diazoque est ensuite copul avec le chlorhydrate de N-naphtyl thylnediamine 
pour fournir un colorant azoque. La mesure de l'absorption s'effectue  550 
nm. La mthode permet de mesurer les concentrations en nitrites dans une gamme 
de concentrations comprise entre 0 et 20 mol/kg-1 et la limite de dtection 
est de 0.01 mol/kg-1. Pour les nitrates, un tage de dilution (rapport 1/2.5) 
a t utilis permettant les analyses dans une gamme de concentrations comprise 
entre 0 et 45 mol/kg-1. La limite de dtection est de 0.1 mol/kg-1.

PRLVEMENT DES CHANTILLONS
Les chantillons destins  l'analyse des sels nutritifs ont t prlevs dans 
des flacons en polythylne de 125 ml immdiatement aprs la remonte de la 
bathysonde sur le navire. 32 chantillons ont t prlevs  chacune des 
stations occupes (sauf dans le cas des stations de faible profondeur). Les 
chantillons ont t ensuite analyss immdiatement sur les chanes  flux 
continu. Pendant la campagne, la cadence d'chantillonnage a t de 20 
chantillons par heure avec des temps de prlvement et de rinage de 2 et 1 
mn respectivement pour les nitrates et silicates et de 1 et 2 mn 
respectivement pour les phosphates et nitrites.


2. CALIBRATIONS:

La calibration des mthodes d'analyse est ralise  chaque station en dbut 
et fin de passage des chantillons avec une gamme de solutions talons 
couvrant la gamme de concentrations mesures. Deux solutions mixtes (nitrates 
et silicates d'une part, nitrites et phosphates, d'autre part) ont t 
prpares chaque jour (les solutions talons prpares quotidiennement ont 
permis ainsi de calibrer 3  4 stations selon les journes). Les 
concentrations des talons utiliss sont donnes dans le tableau 4-1.

                                                                            A13/A14 Tracers, CITHER-3

TABLEAU 4-1: Gammes talons utilises durant la campagne CITHER-3 pour les 
             calibrations des teneurs en sels nutritifs.

                      Gamme talons (Concentrations en mol/l-1)
                   ------------------------------------------------
        N         | 1 |   2  |  3   |  4   |  5   |  6 |  7  |  8
        -----------|---|------|------|------|------|----|-----|----
        Silicates  | 0 | 10   | 20   | 40   | 60   | 80 | 100 | 120
        Nitrates   | 0 | 10   | 20   | 30   | 40   |    |     |
        Phosphates | 0 |  0.5 |  1.0 |  1.5 |  2.0 |    |     |
        Nitrites   | 0 |  0.5 |  1.0 |      |      |    |     |


Les talons de sels nutritifs ont t prpars  partir de sels (produits 
Merck p.a.) schs  l'tuve  105C pendant 3 heures. Les peses de sels sont 
faites en tenant compte de la correction de flottabilit de l'air et les 
volumes de fioles et pipettes ont t contrls par pese (WOCE, 1991). La 
temprature dans le conteneur laboratoire est reste proche de 20C pendant la 
campagne et aucune correction de volume n'a t applique.


3. CALCULS:

Du fait de l'utilisation d'eau dionise comme rfrence pour les mesures, la 
densit optique mesure  partir des colorimtres doit tre corrige. En 
effet, lorsque l'eau de mer circule dans la cuve de mesure, une absorption 
parfois importante par rapport  l'eau dionise peut tre observe. Cette 
absorption dpend:

  de la turbidit propre  l'eau de mer qui est due aux matires organiques 
   dissoutes et particulaires, dissoutes ou minrales ;
  de la gomtrie de la cuve de mesure et du rglage optique du colorimtre
  des ractifs tels que les tensio-actifs qui peuvent donner une lgre 
   absorbance lors du mlange avec l'eau de mer.

Une correction de ces diffrents effects dfinis comme correction de 
<turbidit> a t applique  chaque rsultat.  Une correction constante a t 
applique pendant lacampagne et la valeur de cette correction a t vrifie  
intervalles rguliers durant la campagne. Elle est gale  0.06 mol/kg-1 pour 
les phosphates et de 0.05 mol/kg1 pour les nitrites. Elle est nulle pour les 
nitrates et silicates en raison principalement des dilutions appliques sur 
ces deux montages.

                                                                            A13/A14 Tracers, CITHER-3

4  PRCISION DES MESURES

La prcision des mesures a t apprcie comme la rptabilit des rsultats 
obtenue sur des sries d'chantillons prlevs  un mme niveau au cours de 3 
stations  test . Les rsultats sont donns dans le tableau 4-2. 
L'incertitude sur les mesures de silicates est infrieure ou gale  0.4 
mol/kg-1 (soit 0.3% pour les concentrations mesures les plus leves), celle 
sur les mesures de phosphates est infrieure ou gale  0.02 mol/kg-1 (soit 
0.7% pour les concentrations mesures les plus leves) et celle sur les 
mesures de nitrates est infrieure ou gale  0.5 mol/kg-1 (soit 1.1% pour 
les concentrations mesures les plus leves). Us rsultats de la rptabilit 
en phosphates obtenus  la station 160 n'ont pas t pris en compte du fait de 
problmes rencontrs sur le montage phosphates  cette station. Rapportes  
la pleine chelle dfinie par le WHP (1991), les prcisions (Tableau 4-2: C.V. 
(%) P.E. WHP) sont proches des normes retenues retenues par le WHP: 0.2% pour 
les silicates, 0.4% pour les phosphates et 0.9% pour les nitrates.

D'autre part, la prcision des mesures est contrle, en moyenne  chacune des 
stations et  toutes profondeurs,  partir de l'analyse de doublets obtenus en 
fermant deux bouteilles au mme niveau. La distribution des carts entre les 
doublets est reprsente en fonction du numro de station, de la pression et 
sous forme d'histogramme de frquence pour chacun des trois sels nutritifs 
(figures 4-1, 4-2, 4-3). L'cart est gnralement indpendant de la station et 
de la profondeur indiquant que la rptabilit est reste identique aux trois 
stations  test . L'analyse des histogrammes montre que 77% des carts entre 
doublets sont infrieurs  0.3 mol/kg-1 pour les silicates, 77% sont 
infrieurs  0.3 mol/kg-1 pour les nitrates et 75% sont infrieurs  0.02 
mol/kg-1 pour les phosphates. La rptabillit des mesures, estime par 
l'cart-type sur les diffrences entre les mesures sur chaque doublet est de 
0.3 mol/kg-1 pour les silicates, 0.3 mol/kg-1 pour les nitrates et de 0.03 
mol/kg-1 pour les phosphates.

La prcision des mesures a t galement contrle rgulirement ( 23 
reprises pendant la seconde partie de la campagne) sur des sries de 6 
chantillons prlevs dans une mme bouteille. Les rsultats sont montrs dans 
le tableau 4-3. L'incertitude sur les mesures de silicates (pris comme 
l'cart-type moyen sur la dure de la campagne) est de 0.3 mol/kg-1, pour les 
nitrates de 0.2 mol/kg-1 et de 0.02 mol/kg-1 pour les phosphates. Rapportes 
 la pleine chelle dfinie par le WHP (1991), les prcisions sont de 0.12% 
pour les silicates, de 0.34% pour les nitrates et de 0.31% pour les 
phosphates.


TABLEAU 4-2: Prcision des rsultats de sels nutritifs par l'analyse 
             d'chantillons prlevs  un mme niveau aux stations  test . 
             Le coefficient de variation est indiqu par rapport  la pleine 
             chelle (P.E.) dfinie par le WHP (1991).

      SILICATES
         Numro Station                    | 109    | 160    | 211
         Profondeur (m)                    |        |        |
         Nombre d'chantillons             |  17    |  32    |  32
         Concentration moyenne (mol/kg-1) |  49.16 |  52.83 |  42.98
         cart-type (mol/kg-1)            |   0.40 |   0.22 |   0.31
         C.V. (%)                          |   0.82 |   0.41 |   0.71
         C.V. (%) P.E. WHP (250 mol/kg-1) |   0.16 |   0.09 |   0. 12
      -------------------------------------|--------|--------|--------
       NITRATES                            |        |        |
         Numro Station                    | 109    | 160    | 211
         Profondeur (m)                    |        |        |
         Nombre d'chantillons             |  17    |  32    |  32
         Concentration moyenne (mol/kg-1) |  24.59 |  23.99 |  21.86
         cart-type (mol/kg-1)            |   0.08 |   0.42 |   0.46
         C.V. (%)                          |   0.31 |   1.75 |   2.12
         C.V. (%) P.E. WHP (250 mol/kg-1) |   0.16 |   0.89 |   0.99
      -------------------------------------|--------|--------|--------
       PHOSPHATES                          |        |        |
         Numro Station                    | 109    | 160    | 211
         Profondeur (m)                    |        |        |
         Nombre d'chantillons             |  17    |  32    |  32
         Concentration moyenne (mol/kg-1) |   1.65 |   1.45 |   1.45
         cart-type (mol/kg-1)            |   0.01 |   0.12 |   0.02
         C.V. (%)                          |   0.65 |   8.21 |   0.71
         C.V. (%) P.E. MW (250 mol/kg-1)  |   0.22 |   2.37 |   0.37



FIGURE LEGENDS (see pdf doc for figures)
               
Figure 4-1: Ecarts entre les concentrations de silicates mesures sur deux 
            bouteilles fermes au mme niveau: en fonction du numro de 
            station, en fonction de la pression de fermeture des bouteilles, 
            nombre de doublets par classe d'cart.
            
            
Figure 4-2: carts entre les concentrations de nitrates mesures sur deux 
            bouteilles fermes au mme niveau: en fonction du numro de 
            station, en fonction de la pression de fermeture des bouteilles, 
            nombre de doublets par classe d'cart.
            
            
Figure 4-3: carts entre les concentrations de phosphates mesures sur deux 
            bouteilles fermes au mme niveau: en fonction du numro de 
            station, en fonction de la pression de fermeture des bouteilles, 
            nombre de doublets par classe d'cart.

                                                                            A13/A14 Tracers, CITHER-3

Tableau 4-3: Prcision es rsultats de sels nutritifs par l'analyse 
             d'chantillons prlevs sur une mme bouteille durant la 
             campagne. Le coefficient de variation est indiqu par rapport  
             la pleine chelle (P.E.) dfinie par le VaW (199 1).

NITRATES                                                                                                                        || NITRATES                          
--------------------------------------------------------------------------------------------------------------------------------|| --------------------------------- -----------------------------------------------------------------------------------------------
Numro Station                  | 123   | 126   | 130   | 136   | 141   | 146   | 115   | 154   | 158   | 165   | 176   | 181   || Numro Station                  | 184   | 188   | 191   | 197   | 200   | 204   | 207   | 220   | 225   | 230   | 233   | 237
Date                            | 25/02 | 26/02 | 27/02 | 01/03 | 02/03 | 03/03 | 04/03 | 05/03 | 06/03 | 11/03 | 12/03 | 13/03 || Date                            | 14/03 | 15/03 | 16/03 | 17/03 | 18/03 | 19/03 | 20/03 | 23/03 | 24/03 | 25/03 | 26/03 | 27/03
Quart                           | 0-4   | 4-8   | 0-4   | 0-4   |       | 0-4   | 0-4   |       | 0-4   | 0-4   | 0-4   | 0-4   || Quart                           | 8-12  | 0-4   | 8-12  |       |       | 4-8   | 8-12  | 8-12  | 8-12  | 0-4   |       | 8-12
Bouteille                       | 14    | 20    | 27    | 21    |       | 1     | 1     |       | 1     | 2     | 15    | 6     || Bouteille                       | 7     | 27    | 8     |       |       | 11    | 12    | 19    | 18    | 17    |       | 16
Concentration moyenne (mol/Kg) | 25.7  |       | 12.4  | 33.8  | 24.5  |       | 29.6  | 25.1  | 30.1  | 31.3  | 23.7  |       || Concentration moyenne (mol/Kg) | 24.0  | 35.0  | 23.1  | 23.7  | 39.3  | 23.8  | 22.9  | 34.7  | 20.4  | 20.9  | 21.7  | 21.4
Ecart-type (mol/Kg)            |  0.08 |       |  0.04 |  0.22 |  0.10 |       |  0.26 |  0.17 |  0.27 |  0.13 |  0.17 |       || Ecart-type (mol/Kg)            |  0.10 |  0.25 |  0.29 |  0.06 |  0.24 |  0.07 |  0.12 |  0.09 |  0.10 |  0.26 |  0.28 |  0.09
C.V. (%)                        |  0.32 |       |  0.33 |  0.66 |  0.42 |       |  0.87 |  0.66 |  0.91 |  0.41 |  0.70 |       || C.V. (%)                        |  0.42 |  0.73 |  1.26 |  0.26 |  0.61 |  0.29 |  0.54 |  0.24 |  0.47 |  1.23 |  1.29 |  0.41
C.V.P.E. WHP (47 mol/Kg)       |  0.18 |       |  0.09 |  0.48 |  0.22 |       |  0.55 |  0.35 |  0.58 |  0.27 |  0.35 |       || C.V.P.E. WHP (47 mol/Kg)       |  0.21 |  0.54 |  0.62 |  0.13 |  0.51 |  0.15 |  0.26 |  0.18 |  0.20 |  0.55 |  0.59 |  0.19

SILICATES                                                                                                                       || SILICATES                                                                                               
--------------------------------------------------------------------------------------------------------------------------------||--------------------------------- -----------------------------------------------------------------------------------------------
Numro Station                  | 123   | 126   | 130   | 136   | 141   | 146   | 150   | 154   | 158   | 165   | 176   | 181   || Numro Station                  | 184   | 188   | 191   | 197   | 200   | 204   | 207   | 220   | 225   | 230   | 233   | 237
Date                            | 25/02 | 26/02 | 27/02 | 01/03 | 02/03 | 03/03 | 04/03 | 05/03 | 06/03 | 11/03 | 12/03 | 13/03 || Date                            | 14/03 | 15/03 | 16/03 | 17/03 | 18/03 | 19/03 | 20/03 | 23/03 | 24/03 | 25/03 | 26/03 | 27/03
Quart                           | 0-4   | 4-8   | 0-4   | 0-4   |       | 0-4   | 0-4   |       | 0-4   | 0-4   | 0-4   | 0-4   || Quart                           | 8-12  | 0-4   | 8-12  |       |       | 4-8   | 8-12  | 8-12  | 8-12  | 0-4   |       | 8-12
Bouteille                       | 14    | 20    | 27    | 21    |       | 1     | 1     |       | 1     | 2     | 15    | 6     || Bouteille                       | 7     | 27    | 8     |       |       | 11    | 12    | 19    | 18    | 17    |       | 16
Concentration moyenne (mol/Kg) | 53.2  |       | 4.8   | 63.2  | 51.3  | 110.4 | 108.5 | 59.0  | 110.6 | 110.3 | 34.2  | 54.3  || Concentration moyenne (mol/Kg) | 54.0  | 15.5  | 54.1  | 53.8  | 20.1  | 54.4  | 49.9  | 28.2  | 23.7  | 33.2  | 31.9  | 33.7
Ecart-type (mol/Kg)            |  0.27 |       |  0.00 |  0.34 |  0.37 |  0.75 |  1.00 |  0.00 |  0.32 |  0.28 |  0.20 |  0.11 || Ecart-type (mol/Kg)            |  0.23 |  0.08 |  0.07 |  0.11 |  0.23 |  1.17 |  0.49 |  0.13 |  0.13 |  0.21 |  0.20 |  0.09
C.V. (%)                        |  0.51 |       |  0.00 |  0.54 |  0.73 |  0.67 |  0.92 |  0.00 |  0.29 |  0.25 |  0.58 |  0.20 || C.V. (%)                        |  0.43 |  0.52 |  0.13 |  0.20 |  1.14 |  2.15 |  0.98 |  0.46 |  0.55 |  0.63 |  0.63 |  0.27
C.V.P.E. WHP (250 mol/Kg)      |  0.11 |       |  0.00 |  0.14 |  0.15 |  0.30 |  0.40 |  0.00 |  0.13 |  0.11 |  0.08 |  0.04 || C.V.P.E. WHP (250 mol/Kg)      |  0.09 |  0.03 |  0.03 |  0.04 |  0.09 |  0.47 |  0.20 |  0.05 |  0.05 |  0.08 |  0.08 |  0.04

PHOSPHATES                                                                                                                      || PHOSPHATES                                                                                              
--------------------------------------------------------------------------------------------------------------------------------||--------------------------------- -----------------------------------------------------------------------------------------------
Numro Station                  | 123   | 126   | 130   | 136   | 141   | 146   | 150   | 154   | 158   | 165   | 176   | 181   || Numro Station                  | 184   | 188   | 191   | 197   | 200   | 204   | 207   | 220   | 225   | 230   | 233   | 237
Date                            | 25/02 | 26/02 | 27/02 | 01/03 | 02/03 | 03/03 | 04/03 | 05/03 | 06/03 | 11/03 | 12/03 | 13/03 || Date                            | 14/03 | 15/03 | 16/03 | 17/03 | 18/03 | 19/03 | 20/03 | 23/03 | 24/03 | 25/03 | 26/03 | 
Quart                           | 0-4   | 4-8   | 0-4   | 0-4   |       | 0-4   | 0-4   |       | 0-4   | 0-4   | 0-4   | 0-4   || Quart                           | 8-12  | 0-4   | 8-12  |       |       | 4-8   | 8-12  | 8-12  | 8-12  | 0-4   |       | 8-12
Bouteille                       | 14    | 20    | 27    | 21    |       | 1     | 1     |       | 1     | 2     | 15    | 6     || Bouteille                       | 7     | 27    | 8     |       |       | 11    | 12    | 19    | 18    | 17    |       | 16
Concentration moyenne (mol/Kg) |  1.67 |  2.35 |  0.90 |  2.30 |  1.63 |  2.20 |  2.14 |  1.73 |  2.12 |  2.14 |  1.55 |  1.58 || Concentration moyenne (mol/Kg) |  1.57 |  2.23 |  1.56 |  1.54 |       |  1.54 |  1.49 |  2.38 |  1.33 |  1.38 |  1.41 |  1.39
Ecart-type (mol/Kg)            |  0.02 |  0.01 |  0.01 |  0.02 |  0.01 |  0.02 |  0.02 |  0.01 |  0.04 |  0.01 |  0.03 |  0.02 || Ecart-type (mol/Kg)            |  0.01 |  0.01 |  0.01 |  0.02 |       |  0.02 |  0.02 |  0.01 |  0.01 |  0.01 |  0.01 |  0.01
C.V. (%)                        |  1.20 |  0.43 |  1.11 |  0.87 |  0.61 |  0.91 |  0.93 |  0.58 |  1.89 |  0.47 |  1.94 |  1.27 || C.V. (%)                        |  0.64 |  0.45 |  0.64 |  1.30 |       |  1.30 |  1.34 |  0.42 |  0.75 |  0.72 |  0.71 |  0.72
C.V.P.E. WHP (5 mol/Kg)        |  0.40 |  0.20 |  0.20 |  0.40 |  0.20 |  0.40 |  0.40 |  0.20 |  0.80 |  0.20 |  0.60 |  0.40 || C.V.P.E. WHP (5 mol/Kg)        |  0.20 |  0.20 |  0.20 |  0.40 |       |  0.40 |  0.40 |  0.20 |  0.20 |  0.20 |  0.20 |  0.20

                                                                            


RFRENCES BIBLIOGRAPHIQUES

Bendschneider K. & N.J. Robinson, (1952) "A new spectrophotometric 
    determination of nitrite in sea water." J. mar. Res., 11, 87-96.

Fanning K.A. & M.E.Q. Pilson, (1973) "On the spectrophotometric determination 
    of dissolved silica in natural waters." Analyt. Chem., 45, 136-140.

Mullin J.B. & J.P. Riley, (1955) "The spectrophotometric determination of 
    silicate- silicon in natural waters with special reference to sea water." 
    Anal. chim. Acta, 12, 162-170.

Murphy J. & J.P. Riley, (1962) "A modified single solution method for the 
    determination of phosphate in natural waters." Anal. chim. Acta, 27, 
    31-36.

Strickland J.D.H. & T.R. Parsons, (1972) "A practical handbook of sea water 
    analysis." Bull. Fish. Res. Bd. Canada, 167, 310 p.

Trguer P. & P. Le Corre, (1975) Manuel d'analyse des sels nutritifs dans 
    l'eau de mer (Utilisation de l'Autoanalyzer II - Technicon). Universit de 
    Bretagne Occidentale, Brest, 2me dition.

WOCE Operations Manual, (1991) Volume 3: The Observational Program Section 3.1 
    WOCE Hydrographic Program Part 3.1.3.: WHP Operations and Methods. WOCE 
    Report No 68/91, July 1991.

Wood E.D., F.A.J. Armstrong & F.A. Richards, (1967) "Determination of nitrate 
    in sea water by cadmium-copper reduction to nitrite." J. mar. biol. Ass. 
    U.K., 47, 23-31.

                                                                            A13/A14 Tracers, CITHER-3

V  NUTRIENT MEASUREMENTS - WOCE A14
   (Alvarez-Salgado, X.A. and Paz Fernandez, M.J.)
   Instituto de Investigacins Marifias (C.S.I.C.)
   Eduardo Cabello 6, Vigo (SPAIN)



TABLE OF CONTENTS

V.1. SAMPLING PROCEDURE

V.2. EQUIPMENT AND METHODS

     V.2.1. Methods
     V.2.2. Calibration
     V.2.3. Data acquisition

V.3. PRECISION

     V.3.1. Analytical error. Duplicate analyses
     V.3.2. Sampling error. Duplicate samples
     V.3.3. Consistency of measurements. Quality control

V.4. COMPARISON WITH HISTORICAL DATA

V.5. REFERENCES



V.1. SAMPLING PROCEDURE 

Nutrients were sampled after trace gases, dissolved oxygen, total inorganic 
carbon, alkalinity and pH. Samples were drawn into 60 ml solid-polyethylene 
containers. These were rinsed twice before filling. Samples were analysed as 
soon as possible after collection. They were preserved in the dark at 40C 
when analyses started more than 1 hour after collection. In any case, no more 
than 12 h elapsed before analysing.



V.2. EQUIPMENT AND METHODS 

Nutrient analyses were performed by segmented flow analysis (SFA) with an 
autoanalyzer TECHNICON AAII". Nitrate+nitrite, phosphate and silicate were 
determined simultaneously. Samples were transferred into 20 ml Pyrex tubes 
thoroughly rinsed and set into a Gilson(r) automatic sampler, provided with a 
stainless steel needle. A pumping cycle of 3.4 minutes sucking the sample, and 
0.6 minutes rinsing in a milli-Q(r) water reservoir, was used. An analysis spent 
~14.6 ml of sample, which allow us to do replicates when required.

                                                                            A13/A14 Tracers, CITHER-3

V.2.1. METHODS

Determination of nitrate, phosphate and silicate was carried out following the 
methods described by Hansen and Grasshoff (1983), with some modifications. 
Thus, to avoid possible contamination problems when ammonium is determined 
simultaneously (ie., in lab routine analysis), reagents as ammonium salts were 
replaced by the corresponding sodium salts. The most significant change 
regards to the buffer solution used in the determination of nitrate+nitrite 
(see below).

SILICATE: 
Silicate, in the orthosilicate form, was reacted with sodium molybdate to 
produce beta-1:12 silicomolybdic acid. Since the beta-1:12 silicomolybdic acid is 
unstable and has a low molar absorbance, it is subsequently reduced to a blue 
heteropoly acid with a much higher molar absorbance at 660 nm. Ascorbic acid 
was used as reductant. Oxalic acid was introduced to avoid any interference 
due to the formation of similar 1:12 heteropoly acids with phosphate and 
arsenate. Oxalic acid decomposes the phosphomolybdic and arsenomolybdic acids 
eventually formed. The reaction was performed at constant temperature (37C), 
to reduce the dramatic effect of changing temperature, because of the short 
time allowed to produce the beta-1:12 silicomolybdic acid. A 15 mm pathlength 
flowcell was used.

PHOSPHATE: 
Determination of phosphate was based on the reaction of the ions (H3PO4, 
H2PO4-, HP042- and P043-) with an acidified molybdate reagent. A 
phosphomolybdate complex forms under acid conditions, which is subsequently 
reduced to a phosphomolybdenum blue complex, detectable at 880 nm. The 
reaction occurs at 37C. Ascorbic acid was used as reducing agent. A solution 
of dodecyl sulfate (sodium salt) was used as surfactant, instead of Levor IV. 
The latter is not recommended nowadays (Kirkwood et al, 1991), because of 
precipitation problems in samples of high salinity, which lead to absorbances 
higher than with manual methods (Loder and Gilbert, 1977; Hansen and 
Grasshoff, 1983; Alvarez-Salgado et al, 1992). The colorimeter was fitted with 
a 50 mm pathlength flowcell.

NITRATE+NITRITE:
Nitrate was first reduced to nitrite, and nitrate+nitrite was subsequently 
measured as an azodye at 543 nm. A column of 5.4 cm3, filled with copperize 
cadmium granules, is used for nitrate reduction. Peak shape is strongly 
affected by column packing, compromising the accuracy of the measurements. 
Contrary to CITHER-2 (RIV Maurice Ewing), column packing was not affected by 
shipengines vibrations during CITHER-3 (NIO I'Atalante). Reduction efficiency 
was checked by comparing the signals yield by both a nitrate and a nitrite 
standards of similar concentration (~38 mol/kg-1). The Cu/Cd column was 
reactivated three times along the cruise, when the efficiency was less than 
90%. A mixture of citric acid/sodium citrate is used as buffer solution 
(Mouriho and Fraga, 1985), instead of ammonium chloride. Reduction takes place 
at pH 5.3-5.7 when using this buffer solution.

                                                                            A13/A14 Tracers, CITHER-3

V.2.2. CALIBRATION

Primary standards for nitrate+nitrite, phosphate and silicate were prepared 
from nutrient salt materials (KNO3, KH2PO4 and NaSiF6, respectively) dried 24 
h over silica gel water. Primary solutions were made up with milli-Q(r) in 
calibrated volumetric flasks. A stock standard solution was prepared by mixing 
the three primary standards. No chemical preservatives were added; they were 
preserved in the dark at 4C. Finally, working standard solutions to 
simultaneously calibrate the three SFA systems were produced dissolving 
different volumes of the stock standard solution in low nutrient seawater 
(LNSW), filtered to 0.45 m  (see Table V-1). The working standard solutions 
were made up every two days and preserved in the dark at 4C.


TABLE V-1: Set of working standard solutions prepared in LNSW from one of the 
           three stock standard solutions available 

    Standard |     Volume (ml)     |   Concentration (mol/kg-1)
             | Stock  Final Volume | NO3-   | N02-   | HP04 2- | Si02
    ---------|---------------------|--------|--------|---------|-------
        1    |   5       500       | 25.081 |        |  1.992  | 40.923
        2    |  15      1000       | 37.622 |        |  2.981  | 61.385
        3    |  20      1000       |        |        |         | 81.846*
        4    |   5       500       |        | 23.938 |  1.992  |
    -------------------------------------------------------------------
    *EXCEPTION: A stock standard solution with 122.7|7 mol/kg-1 of 
                silicate (15ml stock/500ml LNSW) was prepared the 
                last working day, when high-silicate AABW was sampled.


Three sets of primary standards were prepared to regularly intercalibrate them 
and check their stability along the cruise. The coherence between the three 
sets of primary standards was generally good, except when minor problems of 
contamination during preparation of working standard solutions arose.

In addition, primary standard solutions of nitrite were also prepared by 
dissolving NaNO2 in milli-Q(r) water. NaOH (0.2 gl-1) was added to keep 
alkaline the standard solution, avoiding decomposition. Stock standards were 
also made up by mixing of nitrite and phosphate primary standards. Working 
standards in LNSW were produce to check the efficiency of the Cu/Cd column 
daily.

LINEARITY:
Phosphate signal was linear over the working range (0-3 mol/kg-1). However, 
deviations from linearity were found for nitrate (concentration >25 mol/kg-1) 
and silicate (concentration >40 mol/kg-1). Calibration curves performed in 
the laboratory proved that the analytical system for nitrate can be accurately 
calibrated (within WOCE requirements) by considering two segments (0-25 and 
25-40 mol/kg-1). If a linear response all over the working range (0-40 
mol/kg-1) were assumed, errors as high as 4.3% would be done. Three segments 
(0-40, 40-60 and 60-120 mol/kg-1) were considered for silicate. Maximum 
errors of 2.3% would be obtained if a simple 2-point calibration curve were 
performed. This procedure has been preferred than sample dilution with LNSW.

                                                                            A13/A14 Tracers, CITHER-3

BLANK:
Systematic greater absorbances obtained with SFA systems regarding to manual 
methods are due to variations in the refractive index. When blown glass 
flowcells are used, changes in the refractive index from milli-Q(r) to sea water 
provoke light scattering, with the concomitant change of the optical signal 
(Froelich and Pilson, 1978). To solve this problem, a system blank (zero 
nutrient seawater) with about the same refractive index as LNSW was made up 
dissolving 35 g of sodium chloride (calcined at 600C) in 11 of milli-Q(r) 
water. During calcination, nitrate and ammonium are totally eliminated and 
silicate is converted into non-reactive forms. However, high contents of 
phosphate are still present in the calcined sodium chloride. Therefore, for 
phosphate we use the physical method described by Alvarez-Salgado et al (1992) 
to correct the refractive index effect.

V.2.3. DATA ACQUISITION

Analogic signals from the three colorimeters were acquired by means of 
penrecorders connected to the colorimeter outputs. Signal height was manually 
measured on the graphic records, and compared with the working standards 
height.



V.3. PRECISION 

The WOCE requirements for precision (Joyce et al, 1991) are silicate 0.2% full 
scale (110 mol/kg-1 during CITHER-3, section A14); nitrate 0.2% full scale 
(38 mol/kg-1) and phosphate 0.4% full scale (2.5 mol/kg-1).

V.3.1. ANALYTICAL ERROR. DUPLICATE ANALYSES

Duplicate analyses of the same 60 ml sample container were done regularly 
along the cruise. In addition, analyses were repeated when abnormal peak shape 
compromised the accuracy of any nutrient measurement. A total of 156 duplicate 
analyses of nitrate, 218 of phosphate and 170 of silicate were recorded. Table 
V-2 summarised the absolute difference between duplicate analyses, and the 
absolute difference relative to full scale (CV fs%). CV fs% satisfied the WOCE 
requirements for nitrate, phosphate and silicate.


TABLE V-2: Average absolute difference (in mol/kg-1) between duplicate 
           analyses of the same sample container. 

                                | Nitrate | Phosphate | Silicate
           ---------------------|---------|-----------|---------
           Absolute Difference  |   0.04  |    0.006  |    0.12
           Number of Duplicates | 156     |  218      |  170
           C.V.FS (%)           |   0.11  |    0.24   |    0.11
           WOCE Requirements    |   0.2   |    0.4    |    0.2

                                                                            A13/A14 Tracers, CITHER-3

V.3.2. SAMPLING ERROR. DUPLICATE SAMPLES

A couple of bottles were regularly fired at the same depth in each station 
during CITHER-3, section A14. Such a depth changed randomly from station 
tostation. Table V-3 shows the average absolute differences between samples 
from pairs of bottles fired at the same depth. CV fs% numbers were lower than 
required by WOCE.

TABLE V-3: Average absolute differences (in mol/kg-1) between samples from 
bottles fired at the same depth.

                                | Nitrate | Phosphate | Silicate
           ---------------------|---------|-----------|---------
           Absolute Difference  |   0.05  |    0.004  |    0.09
           Number of Duplicates | 173     |  172      |  174
           C.V.FS (%)           |   0.13  |    0.16   |    0.08
           WOCE Requirements    |   0.2   |    0.4    |    0.2


Distributions of absolute differences versus station number (Figs V-1a, V-2a 
and V-3a) and depth (Figs V-1b, V-2b, and V-3b) are shown. No trend are 
observed for nitrate, phosphate and silicate. Four out-layers (white circles) 
has been identified and removed from the frequency analyses of nitrate. Two of 
them (station 5 at 1551 db and station 98 at 51 db) were also observed in 
phosphate and pH, suggesting a problem with firing depth or bottle hermetism.

Frequency distributions (%) of absolute differences (Figs V-1c, V-2c and V-3c) 
follows the expected normal distribution with -80% of duplicate samples below 
0.1 mol/kg-1 for nitrate, 0.01 mol/kg-1 for phosphate and 0.2 mol/kg-1 for 
silicate.

V.3.3. CONSISTENCE OF MEASUREMENTS. QUALITY CONTROL


The whole set of bottles (thirty) were fired at 3000 db in stations 0 and 45. 
Results are shown in Table V-4. Standard deviation (std) for nitrate was lower 
than 0.07 mol/kg-1. Standard deviation for phosphate was 0.01 mol/kg-1 at 
the first test station but, it was subsequently improved. It was as low as 
0.004 mol/kg-1 at stn 45, about the middle of the cruise. Finally, standard 
deviation for silicate was lower than 0.25 mol/kg-1. The CV fs% was within 
the WOCE requirements in both stations for the three nutrient salts.

TABLE V-4: Summary of average concentration and standard deviation of nutrient 
           masurements at the quality control stations during CITHER-3, Section 
           A14. 

                |         |   AVERAGE   |     STD     | C.V. |   (%)
                | STATION | (mol/kg-1) | (mol/kg-1) | (%)  | C.V. FS
      ----------|---------|-------------|-------------|------|--------
      NITRATE:  |         |             |             |      |      
                |     0   |   22.14     |    0.04     | 0.20 |  0.11
                |    45   |   22.92     |    0.07     | 0.29 |  0.18
      ----------|---------|-------------|-------------|------|--------
      PHOSPHATE:|         |             |             |      |     
                |    0    |    1.449    |    0.011    | 0.77 |  0.44
                |   45    |    1.511    |    0.004    | 0.28 |  0.16
      ----------|---------|-------------|-------------|------|--------
      SILICATE: |         |             |             |      |     
                |    0    |   37.87     |    0.10     | 0.25 |  0.09
                |   45    |   45.48     |    0.27     | 0.60 |  0.25

                                                                            A13/A14 Tracers, CITHER-3

V.5. COMPARISON WITH HISTORICAL DATA 

CITHER-3 stations 44, 75 and 89 have been compared with stations 77 (SAVE 2), 
134 (SAVE 3) and 209 (SAVE 4), respectively. SAVE ("South Atlantic Ventilation 
Experiment") was an American program performed between 1987 and 1988. Compared 
stations are geographically very close.

Nitrate plots of the current data overlay the historical data in the three 
stations compared (Figs V-4a, b and c). Differences are no significant within 
the WOCE requirements. Figs V-5a, b and c shows the comparison between CITHER-
3 and SAVE profiles of phosphate. Agreement with the historical data is good, 
except for station 44 (Fig. V-5a). Station 77 during SAVE 2 shows higher 
phosphate values than station 44 during CITHER-3 all over the water column, 
suggesting a discrepancy in the estimation of the system blank. The difference 
is 0.04 mol/kg-1 for samples deeper than 2000 db.For silicate (Figs. V-6a, b 
and c) CITHER-3 data do not show any significant deviation from the historical 
data. In all cases the consistency between the two data sets is maintained in 
the whole water column. Finally, the relationships between nitrate and 
phosphate, and silicate and nitrate for all samples along CITHER-3, section 
A14, are depicted in Figs V-7a and b, respectively. Regression of nitrate 
versus phosphate illustrate the consistency among nutrients: 

        NO3- = -2.0 (0.8)+16.05 (0.02)HP04 2-, r2= 0.992, n= 3121.

The slope of the linear regression coincides with the classical Redfield's N/P 
ratio.



V.6. REFERENCES 

Alvarez-Salgado X.A., F. Fraga and F.F. Prez, (1992) "Determination of 
    nutrient salts by automatic methods both in seawater and brackish water: 
    the phosphate blank." Marine Chemistry, 39, 311-319

Froelich, P.N. and M.E.Q. Pilson, (1978) "Systematic absorbance errors with 
    Technicon AutoAnalyzer 11 colorimeters." Water Research, 12, 599-603

Hansen, H.P. and K. Grashoff, (1983) Automated chemical analysis, in Methods 
    of seawater analysis, 2nd Edition. edited by K. Grasshoff, M. Ehrhardt and 
    K. Kremling, pp. 347-395, Verlag Chemie, Wheinheim, 1983

Joyce T. and C. Corry, (1994) Editors, Requirements for WOCE hydrographic 
    programme data reporting, WHPO 90-1, rev. 2, 144 pp

Joyce T., C. Corry and M. Stalcup, (1991) Editors, Requirements for WOCE 
    hydrographic programme data reporting, WHPO 90 -1, 71 pp

Kirkwood D., A. Aminot and M. Perttild, (1991) "Fourth intercomparison 
    exercise for nutrients in seawater." Co-operative Research Report No. 174. 
    ICES, Copenhagen, 83 pp

Loder T.C. and P.M. Gilbert, (1977) "Blank and salinity corrections for 
    automated nutrients analysis of estuarine and seawaters." UNH Sea Grant 
    UNH-5G-JR-101 and WHOI Contribution 3897, 29 pp

Mouriho C. and F. Fraga, (1985) "Determinacin de nitratos en agua de mar." 
    Investigacin Pesquera, 49, 81-96



FIGURE LEGENDS (see pdf doc for figures)

Fig V-1. Nitrate absolute difference for duplicate samples fired at the same 
         depth versus station number (a), and pressure (b). Frequency 
         distribution (%) of the absolute differences. White circles are 
         outlayers.

Fig V-2. Phosphate absolute difference for duplicate samples fired at the same 
         depth versus station number (a), and pressure (b). Frequency 
         distribution (%) of the absolute differences. White circles are 
         outlayers.

Fig V-3. Silicate absolute difference for duplicate samples fired at the same 
         depth versus station number (a), and pressure (b). Frequency 
         distribution (%) of the absolute differences.

Fig V-4. Comparison of nitrate profiles for stations occupied at about the 
         same geographical position during CITHER-3 and SAVE cruises

Fig V-5. Comparison of phosphate profiles for stations occupied at about the 
         same geographical position during CITHER-3 and SAVE cruises

Fig V-6. Comparison of silicate profiles for stations occupied at about the 
         same geographical position during CITHER-3 and SAVE cruises

Fig V-7. Nutrient relationships for all samples along CITHER-3, section A14. 
         Nitrate vs. phosphate (a); silicate vs. nitrate (b)

                                                                            A13/A14 Tracers, CITHER-3

VI MESURES DES CHLORONUOROMTHANES F11 ET F12
   (Marie-Jos Messias et Laurent Mernery)
   Laboratoire D'Ocanographie Dynamique et de Climatolologie (LODYC-Paris)


VI.1 TECHNIQUE DE MESURE ET 'CHANTILLONNAGE:

Les mesures des frons ou chlorofluoromthanes F11 (trichlorofluoromthane: 
CFCl3) et F12 (dichlorofluoromthane: CF2CI2) dissous dans l'eau de mer ont 
t ralises  bord par chromatographie en phase gazeuse avec la mme chane 
d'analyse (LODYC) et selon la mme mthode que lors des campagnes ROMANCHE-1 
(Aot 1991) et CITHER-2 (Janvier/Mars 1995). Les chantillons ont t prlevs 
dans des seringues tanches en verre de 100 ml  robinet en mtal puis stocks 
dans des bains  circulation d'eau de mer en attendant l'analyse. La technique 
de mesure des F11 et F12 dissous dans l'eau de mer qui a t suivie, est celle 
de Bullister and Weiss (1988). Les gaz dissous dans les chantillons d'eau de 
nier (aliquote calibre d'environ 30 ml) sont dgazs par bullage de gaz 
vecteur (95% Argon/5% CH4). Les frons contenus dans les chantillons sont 
ensuite pigs slectivement  -40C pendant 4 minutes sur une colonne porasil 
C-porapak T. Aprs un dpigeage  +100C, le F12 et le F11 sont spars et 
quantifis au niveau du chromatographe  dtecteur  capture d'lectrons (GC 
8A - Shimadzu).

Les prlvements et le travail en continu (24h/24) pour les analyses ont t 
assurs sur la base d'un travail organis par quart par une quipe de 4 
personnes:

          Leg 1  Marie-jos Messias | Leg 2  Marie-jos Messias
                 Laurent Memery     |        Gilles Garric
                 Eric Guilyardi     |        Gilles Saragoni
                 Ann Laime          |        Remi Tailleux

Toutes les 243 stations qui ont t occupes ont t chantillonnes en 
frons, cependant une pollution en F12 et une panne du systme de 
refroidissement (probablement lis, cf partie VI.2) a entran une 
interruption totale ou partielle des analyses pour une demidouzaine de 
stations (stations 13, 14, 15, 17, 163, 164, 176). Au total, 6835 chantillons 
d'eau de mer ont t analyss dont 311 doublons (2 chantillons d'eau de mer 
provenant de 2 diffrentes bouteilles hydrographiques mais prleves  la mme 
profondeur lors d'une mme station) et 4 stations tests (toutes les bouteilles 
hydrographiques sont prleves  la mme profondeur). Les mesures des 
concentrations atmosphriques en F11 et F12 effectues quotidiennement, 
comptabilisent par ailleurs 202 chantillons d'air atmosphriques.


V1.2 CALIBRATION DES DONNES:

La concentration en F11 et F12 est mesure par talonnage externe. Le gaz 
standard utilis pendant la campagne est un standard atmosphrique secondaire 
(bouteille d'air comprim fournie par AIR LIQUIDE en 1992) dj utilis pour 
la campagne CITHER-2. Selon les recommandations WOCE, au moins deux 
calibrations de ce standard secondaire par rapport  un standard primaire 
fourni par la Scripps Institution of Oceanography (chelle de calibration SIO) 
ont t ralises avant et aprs la campagne. Les rsultats sont reports sur 
le tableau VI.1.a. Les carts pr-post campagne des teneurs en F11 et F12 du 
standard secondaire ne sont pas significatifs et montrent une excellente 
stabilit de ce standard secondaire. Nous avons retenu comme teneur du 
standard 599 ppt en F12 et 328 ppt en  F11 pour toute la campagne CITHER-3.

                                                                            A13/A14 Tracers, CITHER-3

Tableau VI.1.a: Suivi de l'volution des concentrations en frons du standard 
                AL92.

            Date     | Mesures | F12 ppt |     | F11 ppt |  
            ---------|---------|---------|------|---------|-----
            nov 1994 |   10    | 600.2   | 0.4% | 327.0   | 0.3%
            apr 1995 |   10    | 598.1   | 0.3% | 329.2   | 0.3%


Lors de la campagne, la rptabilit obtenue sur plusieurs sries d'analyses 
de gaz standard (volume inject = 2.95 ml) a t meilleure que  0.4% pour le 
F12 et  0.45% pour le F11 (tableau VI. 1.b


Tableau VI.1.b: Teneurs moyennes en F12 et F11 (aires) pour plusieurs sries 
                 d'injections de 3 ml de standard

          Date     |  F12  |      |  F11   |      | Nombre de mesures
          ---------|-------|-------|--------|-------|------------------
          15/01/95 | 53721 | 0.31% | 121807 | 0.34% |       13
          22/01/95 | 55842 | 0.21% | 120849 | 0.44% |        5
          22/02/95 | 63801 | 0.35% | 120393 | 0.39% |       10
          28/03/95 | 64458 | 0.20% | 112077 | 0.36% |       14


Des courbes de calibration  6 ou 5 niveaux ont t ralises au moins toutes 
les 2 stations par des injections de diffrents volumes de standard. Les 
concentrations en F12 et F11 ont t calcules par un ajustement de ces 
courbes respectivement par un polynme du second degr et du troisime degr. 
Les concentrations en mol/1 ont t converties en pmol/kg en utilisant la 
salinit de l'chantillon et la temprature du bain de stockage des 
chantillons.


V1.3 SUIVI DES CONCENTRATIONS ATMOSPHRIGUES

Des prlvements d'air ont t raliss quotidiennement pour assurer un suivi 
des teneurs atmosphriques (figures VI.3a et b) et une estimation ultrieure 
des carts  la solubilit thorique des concentrations en frons mesurs en 
surface. Les concentrations en F11 et F12 mesures pendant CITHER-3 par 
rapport  celles obtenues durant CITHER-2 (le groupe CITHER-2, 1996) montrent 
respectivement une stabilisation des concentrations en F11 et une faible 
augmentation en F12. Par ailleurs, le gradient quatorial (li  des missions 
industrielles en frons plus fortes dans l'hmisphre nord) des concentrations 
atmosphriques en F12 et surtout en F11 tend aussi  s'attnuer. Ces tendances 
dj observes pendant CITHER-2 sont en accord avec les mesures rcentes des 
stations de mesures atmosphriques ALE/GAGE (R. Weiss, 1995, communication 
personnelle) et sont conscutives  la diminution des missions industrielles 
en frons notamnment dans l'hmisphre nord ces dernires annes suite au 
Protocole de Montral (accord de 1975 et 1988).


Figures VI.3a et b: Teneur atmosphriques en F12 et  F11 pendant CITHER-3.

                                                                            A13/A14 Tracers, CITHER-3

VI.4   OUALIT' DES MESURES:

VI.4.1 EVALUATION DE LA PART DE CONTAMINATION OU BLANCS

Un point critique de l'analyse des frons est le contrle et l'estimation des 
teneurs en frons attribuables  de la contamination ou blanc qui est 
retranch aux valeurs brutes mesures.

BLANC DE LA CHANE D'ANALYSE
La contamination au niveau de la chane d'analyse est estime par l'analyse de 
l'injection ~3ml de gaz vecteur. Le blanc du systme d'analyse gnralement 
nul, a t affect en F12  plusieurs reprises pendant la campagne. Pendant le 
second leg, une cause vidente a t la panne successive des 2 cryoplongeurs 
(liquide rfrigrant = F12) et leur recharge en F12 le 11/03/95. Ceci a 
entran une importante augmentation en F12 dans le laboratoire (tableau 
VI.4.1.a) contrle par la suite  une concentration raisonnable par un 
puissant systme de ventilation du bord (Super-Cobra le 12/03/95).


TABLEAU VI.1.a: Concentrations en F12 et F11 dans le laboratoire frons

         Date     | F12 ppt  | F11 ppt | 
         ---------|----------|---------|
         17/01/95 |    546.9 | 370.3   | 
         19/01/95 |    649.3 | 350.0   | 
         11/03/95 | 233294.0 | 381.0   | 
         12/03/95 |   1327.5 | 345.7   | aprs recharge du
         12/03/95 |  11217.5 | 569.2   | cryoplongeur en F12 aprs
         13/03/95 |   1956.8 | 351.6   | ventilation par Super-cobra
         15/03/95 |   1159.3 | 348.5   | teneur de l'air ventilant le
         15/03/95 |   3708.7 | 358.8   | labo: F12=553.2 F11=277.0
         17/03/95 |    752.4 | 443.2   |  
         18/03/95 |    778.5 | 354.9   | 
         19/03/95 |   1933.4 | 380.2   | 


Blanc de l'analyse d'chantillons d'eau de mer et limite de dtection
La teneur en frons dans les chantillons d'eau de mer due  de la 
contamination (ou "blanc total" incluant des pollutions possibles des 
bouteilles hydrographiques, seringues, stockage, chane d'analyse, etc) est 
value par l'analyse d'eau de mer suppose sans frons (masse d'eau ayant t 
'quilibre avec l'atmosphre avant l'introduction anthropogne des frons). 
Un blanc total a t dtermin par groupe de stations afin de corriger au 
mieux l'volution temporelle pendant la campagne de la contamination en 
particulier en F12. L'valuation du blanc total moyen et son erreur ont t 
estimes  partir de stations tests o toutes les bouteilles sont fermes  un 
mme niveau sans frons. Les rsultats pour les 4 stations de CITHER-3, sont 
reports sur les figures ci-dessous et rsums tableau 4. Ces stations tests 
permettent aussi de mettre en 'vidence les bouteilles ou les seringues 
pollues (teneur hors gamme).


FIGURE VI.4.1.a: Station 0  3000 db de profondeur
FIGURE VI.4.1.b: Station 15  3698 db de profondeur
FIGURE VI.4.1.c: Leg 2 -Station 160  3199 db de profondeur
FIGURE VI.4.1.d: Station 211  3000 db de profondeur


TABLEAU VI.4.1.b: Teneurs moyennes en F12 et F11 (pmol/l) pour diffrentes 
                  sries d'chantillons prlevs dans des eaux "sans frons".

  Stations   |                 | Pres. | Teneurs F12 | Teneurs F11 |   Nombre
Test et date |     Position    |  db.  |   pmol/l    |   pmol/l    | de mesures
-------------|-----------------|-------|-------------|-------------|-----------
  0 (15101)  | N  6 57-W 14 51 | 3000  | 0.08 0.02  | 0.01 0.01  |    30
 45 (27/01)  | S 14 30-W  9 00 | 3698  | 0.0110.004 | 0.0040.003 |    29
160 (06/03)  | S 25 23-E  8 55 | 3199  | 0.0060.002 | 0.0020.002 |    32
211 (21/03)  | S  4 43-E  4 50 | 3000  | 0.0070.003 | 0.0010.001 |    32

                                                                            A13/A14 Tracers, CITHER-3

Les plus fortes teneurs de contaminations ont t mesures  la station 0, 
ceci tant habituellement le cas en dbut de campagne. Notons cependant, les 
teneurs leves en F12 par rapport au F11  la station 0 des  la pollution 
en F12 que nous avons eue pendant les premires stations. Les rinages 
successifs des bouteilles montrent ensuite une dcroissance de la 
contamination en F12 et F11 vers de trs bas niveaux et une bonne 
reproductibilit dans les normes de WOCE. L'valuation moyenne de la 
contamination et son cart-type qui dterminent la limite de dtection pour 
les chantillons d'eaux profondes  faible teneur en frons sont 
respectivement de 0.008 pmol/l et  0.003 pmol/l en F12 et 0.002 pmol/l et  
0.002 pmol/l en F11 (moyenne des 3 stations tests 45, 161 et 211)

VI.4.2 RPTABILIT:

Les figures VI.4.2.a et b montrent les carts obtenus entre les mesures 
effectues lors des 331 doublets. Les carts pour les eaux profondes sont en 
moyenne infrieurs   0.003 pmol/kg pour F11 et   0.004 pmol/kg pour F12. 
Les 'carts pour les eaux de surface et de subsurface riches en frons sont de 
Pordre de  1% pour F11 et F12. Les carts hors gamme ont permis de dceler 
des contaminations ponctuelles au niveau du matriel d'chantillonnage.


FIGURES VI.4.2a et b: Ecarts obtenus entre les mesures effectues lors des 
                      doublets.



VI.5 VALIDATION

Les donnes ont 't valides

  par identification de bouteilles ou de seringues pollu es  partir de 
   doublets de seringue ou de bouteille,
  par comparaisons individuelles des profils F11 et F12.

D'ventuelles corrections sont  attendre aprs confrontation aux autres 
donnes bouteilles.

                                                                            A13/A14 Tracers, CITHER-3

VI.6 REMERCIEMENTS

Nous tenons tout particulirement  remercier Gilles Garric, Eric Guilyardi, 
Ann Laime, Gilles Saragoni et Rmi Tailleux pour leur participation aux 
mesures des chlorofluoromthanes F11 et F12 lors de la campagne CITHER-3. Eric 
Guilyardi a aussi beaucoup aid au traitement des donnes. Nous remercions 
galement Alain Poisson et Bernard Shauer pour le prt de matriel de 
rechange. La campagne CITHER-3 a 't finance par l'IFREMER et le CNRS  
travers le Programme National d'Etude de la Dynanque du Climat (PNEDC). Nous 
remercions aussi les commandants et l'quipage du Navire Ocanographique 
L'Atalante pour leur concours prcieux au cours de cette campagne.



VI.7 RFRENCES

A. Bullister, J. L. and R.F. Weiss, (1988). Dtermination of CCl3F and CCI2F2 
    in seawater and air. Deep-Sea research, 35, 839-853.

Le groupe CITHER-2, (1996). Campagne CITHER-2 NIO Maurice Ewing (4 Janvier-21 
    Mars 1994). Rapport Interne LPO (96-02).

                                                                            A13/A14 Tracers, CITHER-3

VII CARBON SYSTEM 

Four variables define the carbon system: pH, alkalinity, partial pressure of 
carbon dioxide (pCO2) and total inorganic carbon (TIC). Knowledge of two of 
these variables allows to calculate the other two by means of a set of 
equations deduced from the thermodynamic equilibria. During the CITHER-3 
cruise, TIC was analyzed directly by the coulometric method (Section 1) and pH 
and alkalinity were measured by potentiometric methods (Section 2). Using the 
equations of Mehrbach et al (1973) and Weis (1974) TIC and pCO2 were 
calculated. A comparison between measured and calculated TIC is shown in 
Section 3. Surface pCO2 (Section 4) was calculated following the former 
equations. Total organic carbon was analyzed at six stations (Section 5).

1. TOTAL INORGANIC CARBON MEASUREMENTS IN THE SOUTH ATLANTIC: WOCE SECTIONS 
   A14 AND A13 
   (Linda S. Bingler[1], Javier Aristegui[2], Melchor Gonzlez-Dvila[2])
    [1] Pacific Northwest National Laboratory 1529 W. Sequim Bay Rd. Sequim,
        WA 98382 USA
    [2] Universidad de Las Palmas de Gran Canaria. Campus Universitario de 
        Tafira ES 35017 Las Palmas. Spain


1.1. EQUIPMENT AND TECHNIQUES

Water samples were collected using a PASH 6000 rosette (developed at 
Laboratoire de Physique des Oceans, IFREMER, Brest, France) equipped with a 
NeilBrown Mark-Ill CTD and 30 eight-liter, plastic (PVC) bottles. Seawater 
samples were collected along Section A14 at 42 stations to provide full 
profiles Of CT data. Samples were collected from the surface at 11 stations to 
provide upper water column CT data. During Section A13, seawater samples were 
collected at 39 of 132 stations to provide full profiles Of CT data. Samples 
were collected from the surface at 2 stations to provide upper water column CT 
data.

Seawater samples for CT were collected following the procedure described in 
the DOE CO2 Analysis Handbook in 500 ml ground-glass stoppered bottles. 
Samples were preserved immediately after collection by adding 100 ml of a 
saturated mercuric chloride solution to prevent biological production or 
consumption Of CO2. Samples were filled to overflowing, preservative was added 
well below the surface and the bottles were immediately stoppered, providing 
zero headspace. High-vacuum grease was not used to seal the samples. The 
samples were then stored in covered plastic boxes in a cool, dark place prior 
to analysis. Most samples were analyzed within 14 hours of collection. The CT 
concentration was measured using a Single Operator Multi-Parameter Metabolic 
Analyzer (SOMMA) (Johnson et al, 1987, 1993) coupled with coulometric 
detection (DOE CO2 Analysis Handbook). The seawater sample was drawn into a 
calibrated pipette and dispensed into a stripping chamber, where it was 
acidified with 8.5% phosphoric acid. The resultant CO2 was carried into a 
coulometric cell with N2 gas (99.95%) where it was absorbed by and reacted 
with ethanolamine in dimethylsulf oxide. This reaction produced 
hydroxyethylcarbamic acid, causing a pH change and resultant color change 
(from dark blue to colorless) in the thymolphthalein indicator in the 
solution. Light transmission of the solution was monitored continuously by a 
photodetector, electronically connected to the coulometer. The color change 
caused the coulometer to initiate a current that passed through the cell, 
reacting with water to produce hydroxyl (OH-) ions. The OH- produced titrated 
the hydroxyethylcarbamic acid, returning the solution to a dark blue color 
(i.e. the original pH). The computer program calculated the amount of current 
passed through the cell and with titration time, as related by the Faraday 
constant, calculated the number of moles of OH- required to titrate the acid. 
This number was then used to calculate the number of moles of CO2 absorbed to 
form the acid. Results are expressed as mol/kg.
                                                                            A13/A14 Tracers, CITHER-3

1.2. CALIBRATION AND CORRECTIONS

The SOMMA pipette was calibrated weekly while at sea and in the laboratory 
after the cruise. Calibration of the pipette was accomplished by rinsing the 
pipette three times, then filling the pipette completely with deionized water. 
The pipette contents were dispensed into a 10 ml serum bottle, capped with a 
rubber stopper and sealed with aluminum using a crimper. Calibrations 
performed at sea were stored in boxes until they could be weighed and recorded 
in the laboratory. Calibrations performed in the laboratory were weighed and 
recorded immediately. An average pipette volume of 21.1655 ml was used to 
calculate TCO2 results.

Approximately, every 24 hours, the coulometer cell was removed from the 
coulometer, the contents were discarded and the cell was cleaned by drawing 20 
ml of acetone through the frit from the cathode side to the anode side, 
followed by an equal amount of deionized water. This procedure was repeated 
once more in the opposite direction. The cell was dried thoroughly in a drying 
oven. The anode was scrubbed with steel wool and both the cathode and anode 
were rinsed with deionized water and dried in a drying oven. Ethanolamine in 
DIVISO (100 ml) was added to the cathode chamber and 20 ml of potassium iodide 
in DMSO was added to the anode chamber of a clean, dry cell. A few crystals of 
potassium iodide were added to the anode chamber to maintain saturation. A 
cathode and anode were placed in the cell and the cell positioned on the 
coulometer to achieve maximum transmittance. The current was turned on and the 
cell was allowed to equilibrate (DOE CO2 Analysis Handbook). Certified 
reference materials (CRMs) obtained from Dr. Andrew Dickson, were analyzed as 
calibration check standards at a rate of one CRM every thirty samples. A total 
of 68 and 114 CRMs were analyzed on Sections A14 and A13 respectively, with a 
known CO2 concentration of 1987.53 mol/kg, an average concentration of 
1986.45 mol/kg C obtained for Section A14, with a standard deviation of 2.05 
and a mean difference from the known of -1.08 mol/kg C. During Section A13, 
an average CRM result of 1988.46, a standard deviation of 1.66, and a mean 
difference from the known of 0.94 mol/kg C were obtained.

The coulometer was calibrated at sea during Section A14 a minimum of every ten 
samples by dispensing a known mass of CO2 gas (99.995%) (Wilke et. al., 1993) 
from a pair of calibrated gas sample loops (small loop = 1.3069 ml; large loop 
= 1.8245 ml) according to the procedures described in the DOE CO2 Analysis 
Handbook. The CO2 gas was released into an acidified stripper where it was 
carried to the coulometric cell with N2 gas (99.95%). The CO2 was then 
titrated as described above. The gas loop calibration data (calfactor in 
counts/mole; equation 1) was averaged for the Section A14, providing a mean 
calfactor of 1.00349 for calculation of TCO2 results. An average calfactor was 
obtained (1.00527) from the CRM results for the Section A13 and used to 
calculate the TCO2 results.

(1) Calculation of gas sample loop calibration (DOE CO2 Analysis Handbook):

                                               c - (b * t)
                    Calfactor (counts/mole) =  -----------
                                                 n(CO2)

where:
           c = coulometer reading for the gas sample (counts)
           b = background level (counts/min)
           t = titration time (min)
      n(CO2) = the amount of CO2 dispensed from the loop (mol)

                                                                            A13/A14 Tracers, CITHER-3

1.3 PRECISION

Replicate samples were collected at-sea along Sections A14 and A13 and 
analyzed by Dr. Peter Guenther at Scripps Institution of Oceanography (SIO). 
Results (mol/kg C) appear in Tables VII-1 and VII-2 with relative percent 
difference (RPD) representing the comparability of the two replicates analyzed 
at Scripps Institute of Oceanography by manometry. Comparison of at-sea TCO2 
measurements with those made at Scripps were very good with a range of RPD 
from 0.00% to 0.10% for Section A14 and from 0.01% to 0. 15% for Section A13.


TABLE VII-1: Replicate results expressed in mol/kg-1. Section WOCE A14

                    |  Depth   |  At-Sea  | SIO Analysis | SIO Analysis | RPD 
Stn | Cast | Niskin | (meters) | Analysis | Replicate 1  | Replicate 2  | (%)
----|------|--------|----------|----------|--------------|--------------|-----
 10 |  1   |   32   |      6   | 1906.65  |   1910.04    |   N/A        | 
 22 |  1   |   32   |      7   | 2015.61  |   2018.05    |   2017.74    | 0.02
 22 |  1   |   14   |   2802   | 2188.94  |   2189.30    |   2190.22    | 0.04
 49 |  1   |   22   |     33   | 2078.91  |   2078.50    |   2079.13    | 0.03
 49 |  1   |    4   |   1400   | 2199.00  |   2198.41    |   2200.56    | 0.10
 55 |  1   |   32   |      8   | 2077.97  |   2073.87    |   2073.60    | 0.01
 55 |  1   |   10   |   2999   | 2199.18  |   2197.42    |   2197.09    | 0.02
 76 |  1   |   31   |      8   | 2052.56  |   2056.62    |   2056.51    | 0.01
 88 |  1   |   31   |      7   | 2041.59  |   2043.99    |   2043.69    | 0.01
100 |  1   |   31   |      8   | 2058.85  |   2060.94    |   2060.55    | 0.02
   


TABLE VII-2: Replicate results expressed in mol/kg-1. Section WOCE A13

                    |  Depth   |  At-Sea  | SIO Analysis | SIO Analysis | RPD 
Stn | Cast | Niskin | (meters) | Analysis | Replicate 1  | Replicate 2  | (%)
----|------|--------|----------|----------|--------------|--------------|----- 
115 |   1  |   24   |      6   | 2036.95  |   2035.78    |   2037.30    | 0.07
115 |   1  |    4   |   3000   | 2208.94  |   2207.83    |   2207.75    | 0.00
142 |   1  |   32   |      7   | 2036.76  |   2038.35    |   2039.76    | 0.07
142 |   1  |   12   |   3001   | 2205.23  |   2207.50    |   2206.88    | 0.03
179 |   1  |   31   |      9   | 2043.88  |   2046.03    |   2046.05    | 0.00
179 |   1  |   14   |   3000   | 2198.13  |   2200       |   N/A        | 
207 |   1  |   31   |     12   | 1989.99  |   1988.79    |   1988.98    | 0.01
207 |   1  |   13   |   3000   | 2197.66  |   2197.14    |   2197.81    | 0.03
235 |   1  |   31   |      8   | 1925.11  |   1924.09    |   1923.12    | 0.05
235 |   1  |   13   |   2998   | 2194.18  |   2193.76    |   2193.95    | 0.01



1.4. REFERENCES

"Handbook of Methods for the Analysis of the Various Parameters of the Carbon 
    Dioxide System in Sea Water", Dickson, A.G., and Goyet, C., editors, USDOE 
    SRGP 89-7A, Version 2.0, 1994.

Hansen, H.P. and K. Grasshoff, (1983) Automated Chemical Analysis in Methods 
    of Seawater Analysis. K. Grasshof et al eds. Verlag Chemie pp. 3347-3395.

Johnson, K.M., P.J. IeB. Williams, L. Brndstrm, and J. McN. Sieburth, (1987) 
    "Coulometric TCO2 analysis for marine studies: Automation and 
    calibration." Marine Chemistfy 21:117-133.

Wilke, R.J., D.W.R. Wallace, and K.M. Johnson, (1993) "Water-Based, 
    Gravimetric Method for the Determination of Gas Sample Loop Volume." 
    Analytical Chemistry 65:2403-2406.



2. pH AND ALKALINITY MEASUREMENTS - WOCE SECTION A14
   (Aida F. Rios and Trinidad Relldn)
   Instituto de Investigaciones Marinas (IIM). Vigo. (CSIC)

                                                                            A13/A14 Tracers, CITHER-3

2.1 EQUIPMENT AND TECHNIQUES

2.1.1 pH

Seawater samples for pH analysis were collected in 50 ml plastic bottles after 
TIC samples at all station, following the WOCE sequence. Samples were filled 
to overflowing and immediately stoppered.

A Metrohm 654 pH meter with a Ross (Orion 8104) combination glass electrode 
was used. pH measurements were standarised daily, according to the following 
sequence 

  1) to calibrate the combined electrode with the pH 7.413 NBS buffer solution, 

  2) to check the electrode response with a pH 4.008 NBS buffer solution, as 
     described by Prez and Fraga (1987a), 

  3) to adapt the electrode to the strong ionic strength of sea water by means 
     of a pH 4.4 sea water buffer containing 4.0846 g of C8H5K04 and 1.52568 g 
     of B407Na2 .10H20 (borax) in 1 kg of CO2-free seawater.

Temperature at the time of measuring was checked using a platinum resistance 
Pt-100 probe to correct the effect of temperature on pH (Prez and Fraga, 
1987a). All pH values were referred to a standard temperature of 15C (pH15)

2.1.2 ALKALINITY

Following the sampling sequence proposed by WOCE, seawater samples for 
alkalinity were collected after pH samples, in 300 ml plastic bottles. Full 
water column profiles were analyzed at 39 stations and surface water samples 
were collected at all stations.

Alkalinity was measured using an automatic potentiometric titrator "Titrino 
Metrohm", with a Metrohm 6.0233.100 combination glass electrode. 
Potentiometric titrations were carried out with hydrochloric acid ([HCI = 
0.1310) to a final pH of 4.44 (Prez and Fraga, 1987b). The electrodes were 
standardized using NBS buffers of pH 7.413 and the nernstian slope checked 
using a NBS buffer of 4.008. As for pH measurements, a pH 4.4 buffer made up 
in sea water was used to adapt the electrodes to the strong ionic strength of 
sea water. Concentrations are given in mol/kg.

                                                                            A13/A14 Tracers, CITHER-3

2.2 CALIBRATIONS AND CORRECTIONS

2.2.1 pH15

The apparent activity coefficient of hydrogen ions was estimated by ten 
titration curves with acidified sea water (Culberson, 1981), to determine the 
systematic errors produced by variations in the residual liquid-junction 
potential. The curves were linearized and the inverse slope divided by the 
association constants of fluorhydric and sulphuric acid (fasso) gave the 
activity coefficient of the hydrogen ion of our electrode (fHtot). The 
differences (log(fHot/fM)) between the activity coefficients of our electrode 
(fHtot) and those given by Mehrbach et al (1973) at the same salinity and 
temperature with their electrode (fM) were used to correct our pHl5 
determinations by adding these differences (Table VII-3).

At each station, pH of seawater substandard (pHsss) was measured before and 
after each series of samples. The seawater substandard is a "quasi-steady" 
filtered seawater stored into a large container (25 liters). From each 
calibration we get the pHis (pH isoelectric), that is, the pH recorded at zero 
potential. This pHis can vary because of: 1) real variations of the electrode; 
2) changes in the buffer; and/or 3) an error during the calibration. The 
electrode variation is continuous, as shown in figure VII-1. The same figure 
shows the pHsss variation just after each calibration. The same pattern was 
observed in the two distributions.

In figure VII-2 the variation of pHsss for each station is presented. After 
the calibration the pHsss is generally higher and, it decreases along the 
session of analysis. We assume a daily linear evolution of pHsss and the 
variations along the same day are assumed to be due to the changes in the 
electrode behaviour. Two regression lines can be drawn with the same slope but 
different y-intercept. One using all data and the other one using only 
seawater substandards measured just after the calibration (black points in 
fig. VII-2). The anomalies (&SSS) of each pHsss from the regression, shown in 
figure VII-2, were used to correct the pH15 obtained.

In order to check the procedure followed during the pH determinations, samples 
Of CO2 reference material (CRM) of batch 24 were analyzed during the cruise. 
Figure VII-3 shows the distribution of pHsss (open squares) and CRM (points) 
along the cruise analysed at the same station. The standard deviation of CRM 
samples is 0.009. Once CRM were corrected using the anomalies of SSS and 
Culberson (diamond), the standard deviation became lower (0.004).


TABLE VII-3: Slope from linearized Culberson curves, and the activity 
             coefficients of our electrode (fHtot) and those given by Mehrbach 
             et al (1973) at the same salinity and temperature with their 
             electrode (fM).

    Stn |  Date  | Salinity | T (C) | Slope | fHtot |  fM   | Log(fHtot/fM)
    ----|--------|----------|--------|-------|-------|-------|--------------
      1 | 17-Jan |  34.327  |  24.9  | 1.034 | 0.702 | 0.677 |    0.016
      1 | 17-Jan |  34.327  |  24.6  | 1.032 | 0.704 | 0.678 |    0.016
     24 | 22-Jan |  34.443  |  23.4  | 1.037 | 0.707 | 0.685 |    0.013
     24 | 22-Jan |  34.443  |  25.1  | 1.033 | 0.701 | 0.676 |    0.016
     51 | 28-Jan |  34.821  |  23.5  | 1.040 | 0.703 | 0.685 |    0.011
     51 | 28-Jan |  34.821  |  23.5  | 1.046 | 0.699 | 0.685 |    0.009
     81 | 05-Feb |  34.777  |  20.8  | 1.025 | 0.727 | 0.701 |    0.016
     81 | 05-Feb |  34.777  |  20.8  | 1.033 | 0.721 | 0.680 |    0.012
    107 | 12-Feb |  34.290  |  17.8  | 1.011 | 0.752 | 0.716 |    0.021
    107 | 12-Feb |  34.290  |  17.8  | 1.015 | 0.749 | 0.716 |    0.020
----------------------------------------------------------------------------
       fHtot = (1/slope)/faso = activity coefficient of our electrode 
       fM    = activity coefficient according to Mehrbach et al (1973)
       Log(fHtot/fM) is the difference between both activity coefficients, 
                     used to correct the final pH titrations

                                                                            A13/A14 Tracers, CITHER-3

2.2.2 ALKALINITY

A couple of titration curves per week were performed in sea water with 
hydrochloric acid, according to Culberson (1981), to determine the systematic 
errors produced by variations of residual liquid-junction potential. The 
curves were linealized and the inverse slope divided by the association 
constants of fluorhydric acid and sulphuric acid (fasso) gave the activity 
coefficient of the hydrogen ion of our electrode (fHtot). The differences 
(log(fHtot/fM)) between the activity coefficients of our electrode (fHtot) and 
those given by Mehrbach et al (1973) at the same salinity and temperature with 
their electrode (fM) were used to correct the final pH titrations by adding 
these differences (Table VII-4), allowing comparison with results obtained 
using Mehrbach equations.

Surface seawater stored in 25 liters plastic containers was used as alkalinity 
seawater substandard (SSS). These SSS were analyzed, at the beginning and the 
end of each series of samples. Figure VII-4 represents the variation of SSS 
alkalinity along the cruise. The anomalies obtained from the equation were 
used to correct the alkalinity results.

Determinations of CRM alkalinity were made during the cruise to verify the 
alkalinity analyses. Figure VII-5 shows the CRM alkalinities analyzed and once 
corrected with Culberson curves and SSS anomalies. The standard deviations 
were 5.2 mol/kg-1 CRM, 2.2 mol/kg-1 when corrected with Culberson curves and 
1.4 mol/kg-1 once corrected with SSS anomalies besides.


TABLE VII-4: Slope from linearized Culberson curves, and the activity 
             coefficients of our electrode (fHtot) and those given by Mehrbach 
             et al (1973) at the same salinity and temperature with their 
             electrode (fM).

   Stn | Date   | Salinity | T (C) | Slope | fHtot | fM Log | (fHtot/fM)
   ----|--------|----------|--------|-------|-------|--------|-----------
     1 | 17-Jan |  34.327  |  24.5  | 1.173 | 0.621 | 0.679  |   -0.039
     1 | 17-Jan |  34.327  |  24.6  | 1.174 | 0.619 | 0.678  |   -0.039
     4 | 18-Jan |  34.327  |  25.1  | 1.139 | 0.636 | 0.676  |   -0.026
     4 | 18-Jan |  34.327  |  25.1  | 1.138 | 0.637 | 0.676  |   -0.026
    25 | 22-Jan |  34.443  |  24.6  | 1.127 | 0.645 | 0.679  |   -0.022
    25 | 22-Jan |  34.443  |  24.4  | 1.119 | 0.651 | 0.680  |   -0.019
    46 | 28-Jan |  34.821  |  22.9  | 1.137 | 0.646 | 0.687  |   -0.028
    52 | 28-Jan |  34.821  |  23.3  | 1.056 | 0.694 | 0.689  |    0.005
    52 | 28-Jan |  34.821  |  22.9  | 1.059 | 0.694 | 0.689  |    0.003
    76 | 03-Feb |  34.777  |  22.1  | 1.032 | 0.715 | 0.693  |    0.014
    76 | 03-Feb |  34.777  |  22.3  | 1.030 | 0.716 | 0.692  |    0.015
   107 | 11-Feb |  34.290  |  18.5  | 1.008 | 0.751 | 0.712  |    0.023
   107 | 11-Feb |  34.290  |  18.5  | 1.013 | 0.747 | 0.712  |    0.021
-------------------------------------------------------------------------
     fHtot = (1/slope)/faso = activity coefficient of our electrode 
     fM    = activity coefficient according to Mehrbach et al (1973) 
     Log(fHtot/fM) is the difference between both activity coefficients, 
                   used to correct the final pH titrations

                                                                            A13/A14 Tracers, CITHER-3

2.3 PRECISION

2.3.1. ANALYTICAL ERROR. DUPLICATE ANALYSIS

During the cruise, some replicate analysis of pH and alkalinity from the same 
Niskin bottle were done. Table VII-5 shows the average of absolute differences 
between replicate analysis and the relative error (CV%) on pH15 and alkalinity 
respectively.


TABLE VII-5: Differences between duplicate analysis coming from the same 
             bottle
                                              |  pH15  | Alkalinity
         -------------------------------------|--------|-----------
         Absolute differences average         |  0.004 |    0.9
         STD                                  |  0.003 |    0.7
         CV% (STD  1OO/Averaqe)              |  0.034 |    0.03
         Number of sampled bottles replicated | 10     |   36


2.3.2 SAMPLING ERROR. DUPLICATE SAMPLES

Precision of the pH and alkalinity method was estimated using the analyses of 
174 and 61 couples of samples respectively, corresponding to couples of 
oceanographic bottles fired at the same depth at each station. Table VII-6 
summarizes the differences.


TABLE VII-6. Differences between samples fired at the same depth

                                              |   pH15  | Alkalinity
         -------------------------------------|---------|-----------
         Absolute differences average         |   0.003 |    1.1
         STD                                  |   0.002 |    1.1
         CV%                                  |   0.025 |    0.05
         Number of sampled bottles replicated | 174     |   51


Figure VII-6 shows the pH15 absolute difference versus station number and 
pressure, and the frequency distribution percentage in function of the 
difference. The analysis of the histograms shows that 90% of the differences 
are lower than 0.006 units of pH15. The mean absolute difference is 0.003 that 
in terms of percentage of difference represents 0.038%.

Figure VII-7 shows the alkalinity absolute difference versus station number 
and pressure, and the frequency percentage distribution in function of the 
difference intervals. The frequency histograms of alkalinity show that 90% of 
the differences are lower than 2 mol/kg. The mean absolute difference is 1.1 
mol/kg that in terms of percentage of difference represents 0.05%.

                                                                            A13/A14 Tracers, CITHER-3

2.3.3 ERROR TRANSMISSION TO PCO2 AND TIC

We have calculated the error transmission to pCO2 and TIC due to the 
variations of pH15 and alkalinity. To calculate these transmissions we have 
used the average values of pH15, alkalinity, salinity and temperature of all 
data obtained during the cruise. In Table VII-7 appears the error transmission 
of pH15 and alkalinity to pCO2 and TIC. A variation of 0.003 -average value of 
duplicates- in pH15 transmits 3.5 atm to pCO2 (0.79%) and 1.2 mol/kg to TIC 
(0.05%). While a variation of 1.1 mol/kg - average value of duplicates - 
transmits 0.2 atm to pCO2 (0.05%) and 1.1 mol/kg to TIC (0.05%).

Silicate and phosphate contribute to increase the total alkalinity (Millero, 
1995), especially in deep waters when their concentrations are higher. As TIC 
is calculated using pH15 and alkalinity, the effect of silicate and phosphate 
must be subtracted. This effect has been taken into account in the calculation 
of TIC that appears in the present data base.


TABLE VII-7: Error transmission of pH15 and alkalinity to pCO2 and TIC using 
             the equations of Mehrbach et al (1973) and Weiss (1974) and the 
             average values of pH15, alkalinity, salinity and temperature.

             Error Transmission of pH15. & pH15 = 0.003 (duplicate bottles)
                pH15         | pCO2  | TIC
                -------------|-------|-------
                7.989        | 444.1 | 2187.2
                7.986        | 447.6 | 2188.5
                7.992        | 440.6 | 2186.0
                Transmission |   3.5 |    1.2
             (S = 34.915; T = 6.24; Alk = 2335.5)
             
             Error Transmission of Alkalinity. & Alk = 1.1 (duplicate bottles)
                Alk          | pCO2  | TIC
                -------------|-------|-------
                2335.5       | 744.1 | 2187.2
                2334.4       | 443.8 | 2186.2
                2336.6       | 444.3 | 2188.3
                Transmission |   0.2 |    1.1
             (S = 34.915; T = 6.24; pH15 = 7.989)


2.3.4 QUALITY CONTROL. CONSISTENCY OF MEASUREMENTS.

Quality control was performed two times during the cruise (stations 0 and 45) 
where the whole set of oceanographic bottles were closed at the same depth 
(3000 meters). Results are shown in Table VII-8. The standard deviations for 
pH15 determinations is the same in both cases. However for alkalinity 
analysis, the STD value in station 0 is two times the STD in station 45. In 
both cases the results are into the expected accuracy of the method.

                                                                            A13/A14 Tracers, CITHER-3

TABLE VII-8: Summary of differences between quality control measurements for 
             pH15 and alkalinity

                 | pH15                    | Alkalinity (mol/kg)
             ----|-------------------------|---------------------
             Stn | Average | STD   | CV%   | Average | STD | CV%
             ----|---------|-------|-------|---------|-----|-----
              0  | 7988    | 0.002 | 0.022 | 2338.8  | 1.4 | 0.06
             45  | 7.987   | 0.002 | 0.023 | 2344.6  | 0.7 | 0.03


TABLE VII-9: CRM (batch 24) results of pH15, alkalinity, pCO2, TIC and TIC 
             corrected for phosphate and silicate.

               |       |    Alk    |    TIC   | TIC-(&PO4+&SiO4) | pCO2 
       Station | pH15  | (mol/kg) | (mol/kg)|    (mol/kg)     | atm
       --------|-------|-----------|----------|------------------|------
          1    | 8.211 |   2219    |   1987.7 |     1987.0       | 345.0
          4    | 8.210 |   2218    |   1987.3 |     1986.6       | 345.8
         10    | 8.211 |   2217    |   1985.4 |     1984.7       | 344.6
         13    | 8.208 |   2218    |   1988.4 |     1987.7       | 348.3
         19    | 8.204 |   2215    |   1987.7 |     1987.0       | 351.0
         25    | 8.202 |   2215    |   1988.6 |     1988.0       | 353.5
         31    | 8.205 |   2217    |   1988.7 |     1988.0       | 350.7
         34    | 8.207 |   2217    |   1987.8 |     1987.2       | 349.0
         45    | 8.206 |   2217    |   1988.0 |     1987.3       | 349.9
         52    | 8.206 |   2219    |   1989.8 |     1989.1       | 349.9
         61    | 8.195 |   2219    |   1995.5 |     1994.9       | 360.5
         64    | 8.203 |   2214    |   1987.3 |     1986.7       | 352.4
         73    | 8.200 |   2217    |   1991.1 |     1990.4       | 355.1
         79    | 8.204 |   2218    |   1990.0 |     1989.3       | 351.3
         85    | 8.210 |   2219    |   1987.9 |     1987.3       | 346.3
         97    | 8.211 |   2217    |   1986.2 |     1985.5       | 344.9
        103    | 8.208 |   2216    |   1986.7 |     1986.0       | 347.5
       -----------------------------------------------------------------
       Average | 8.206 |   2217.2  |   1988.5 |     1987.8       | 349.7
       STD     | 0.004 |      1.4  |      2.2 |        2.2       |   4.0


To check the accuracy and consistency of our measurements, a primary standard 
(CRM) has been used along the cruise. The CRM determinations of pH15 and 
alkalinity were corrected following the procedure explained before. The CRM 
results for pH15, alkalinity, TIC and pCO2 (Table VII-9), have been averaged 
for each station. Table VII-10 gathers the results of pH15, alkalinity and TIC 
given by Gonzlez-Dvila, O'Sullivan and Millero and Dickson (pers. com.). Our 
results are in very good agreement with the values assigned by these authors 
to batch 24.
                                                                            A13/A14 Tracers, CITHER-3

TABLE VII-10: CRM (batch 24) analysis of pH15, alkalinity, TIC, phosphate and 
              silicate given by other authors

                     |       |    Alk    |    TIC    |    P04    |   Si04 
Author               | pH15  | (mol/kg) | (mol/kg) | (mol/kg) | (mol/kg)
---------------------|-------|-----------|-----------|-----------|----------
Gonzlez-Dvila      | 8.203 |           |           |           |
O'Sullivan & Millero |       | 2216.01  |           |           |
Dickson              |       |           |  1987.55  |           |
Dickson              |       |           |           |    0.53   |
Dickson              |       |           |           |           |   0.81


2.4  VALIDATION OF ALKALINITY AND TIC RESULTS. COMPARISON WITH SAVE CRUISES

In order to verify our results, comparison between stations 43, 76 and 88 of 
CITHER-3 and 75, 135 and 209 of the SAVE programme, located around the same 
geographical position was done. Figure VII-8 compares the vertical 
distribution of alkalinity among these three sets of stations. It can be seen 
a good coherence between the profiles of stations 43 (CITHER-3) and 75 (SAVE). 
The average difference is 0.97.2 mol/kg. Alkalinities from SAVE are higher 
than ours from 0 to 50 db and from 200 db to the bottom, being our data higher 
between 75 and 200 db. This is the reason of the high standard deviation 
found. The comparison between station 76 (CITHER-3) and 135 (SAVE) shows that 
our values are higher than SAVE data up to 800 db. The average difference is 
4.44.3 mol/kg. Stations 88 (CITHER-3) and 209 (SAVE) present the highest 
difference (average 7.56.1 mol/kg-1).

With regard to the TIC, the comparison between stations 43, 76 and 88 of 
CITHER-3 and stations 75, 135 and 209 of SAVE (fig. VII-9) shows some 
differences between the three couples of profiles obtained. In all cases our 
numbers are lower than SAVE data obtained seven years before, giving average 
differences of 5.910.5, 7.0 10.6 and 7.75.9 mol.kg-1.


2.5 REFERENCES

Culberson, C. H., (1981) "Direct potentiometry in marine electrochemistry." 
    Marine Electrochemistry. Ed. Whitfield and Jagner. J.Wiley and sons Ltd. 
    522 pp.

Mehrbach, C., C.H. Culberson, J.E. Hawley and R.M. Pytkowicz, (1973) 
    "Measurements of the apparent dissociation constant of carbonic acid in 
    seawater at atmospheric pressure." Limnol. Ocean., 18, 897-907.

Millero, F.J., (1995) "Thermodynamics of the carbon dioxide system in the 
    oceans." Geochimica et Cosmochimica Acta, 59, 661-677.

Prez, F.F. and F. Fraga, (1987) "The pH measurements in seawater on NBS 
    scale." Mar. Chem., 21, 315-327.

Prez, F.F. and F. Fraga, (1987) "A precise and rapid analytical procedure for 
    alkalinity determination." Mar. Chem., 21, 169-182.

Weiss, R.F., (1974) "Carbon dioxide in water and seawater: The solubility of a 
    non-ideal gas." Mar. Chem., 2, 203-215.

                                                                            A13/A14 Tracers, CITHER-3

3. INTERNAL CNSISTENCY OF THE CARBONATE SYSTEM MEASUREMENTS 
   (A.F. Ros[1], L.S. Bingler[1], T. Relln[2], J. Arstegui[3])
    [1] Instituto de Investigaciones Marinas. CSIC. Vigo. Spain
    [2] Batelle National Laboratory. Washington. USA
    [3] Facultad de Ciencias. Universidad de Las Pasmas de Gran Canaria. Spain

During the first leg (WOCE Section A14) of CITHER-3 cruise, an 
intercalibration between the total inorganic carbon (TIC) team and 
alkalinity/pH team was made. Both teams used the same CO2 certified reference 
materials (CRMs), batch 24, provided by Dr. Dickson of University of 
California. Results of the CRM analyses of TIC and alkalinity/pH are given in 
Sections 1 and 2 respectively.

Figure VI-10 shows the good correlation (r 2=0.998) obtained between the TIC 
directly measured using the coulometric method (Section 1) and the TIC 
calculated from pH15 and alkalinity, using the equations of Mehrbach et al 
(1973). As it has been explained in Section 2, the effect of silicate and 
phosphate on the total alkalinity has been corrected using the equations given 
by Millero (1995). The average difference between measured and calculated TIC 
was -0.13.0 mol/kg-1 and the slope of the correlation 1.0050.002.

An additional comparison was made with replicate samples collected at seven 
stations during the cruise, and subsequently analysed at the Scripps 
Institution of Oceanography (SIO). Table VII-11 shows the average values of 
TIC replicate analysis made by SIO and the measured al calculated TIC 
performed at sea. The correlations between SIO, measured and calculated TIC 
were in all cases very good. The average difference was very similar 0.92.4 
and 0.92.6 mol/kg-1 There is not only an internal consistecy between 
measured and calculated TIC during the cruise, but also consistence in the 
external comparison with CRMs and with analysis made by SIO. Consequently, 
shipboard carbonic data obtained during Section A14 have high accuracy, and 
became solid for further studies.


TABLE VII-11: Comparison of TIC between the analysis made by SIO with measured 
              and calculated TIC (TICm and TICc). Expressed in mol/kg-1.

        Stn | Bottle |  TICm  |  TICc  |  SIO   | SI0-TICm | SIO-TICc
        ----|--------|--------|--------|--------|----------|---------
         10 |   32   | 1906.7 | 1903.7 | 1910.0 |    3.4   |    6.4
         22 |   32   | 2015.6 | 2015.6 | 2017.9 |    2.3   |    2.3
         22 |   14   | 2188.9 | 2188.4 | 2189.8 |    0.8   |    1.3
         49 |   22   | 2078.9 | 2077.1 | 2078.8 |   -0.1   |    1.7
         49 |    4   | 2199.0 | 2202.1 | 2199.5 |    0.5   |   -2.6
         55 |   32   | 2078.0 | 2075.5 | 2073.7 |   -4.2   |   -1.8
         55 |   10   | 2199.2 | 2200.0 | 2197.3 |   -1.9   |   -2.8
         76 |   31   | 2052.6 | 2056.0 | 2056.6 |    4.0   |    0.5
         88 |   31   | 2041.6 | 2041.9 | 2043.8 |    2.3   |    1.9
        100 |   31   | 2058.9 | 2059.0 | 2060.7 |    1.9   |    1.7
        Average difference                      |    0.9   |    0.9
        Standard deviation                      |    2.4   |    2.6


REFERENCES

Mehrbach, C., C.H. Culberson, J.E. Hawley and R.M. Pytkowicz, (1973) 
    "Measurements of the apparent dissociation constant of carbonic acid in 
    seawater at atmospheric pressure." Limnol. Ocean., 18, 897-907.

Millero, F.J., (1995) "Thermodynamics of the carbon dioxide system in the 
    oceans." Geochimica et Cosmochimica Acta, 59, 661-677.

Weiss, R.F., (1974) "Carbon dioxide in water and seawater: the solubility of a 
    non-ideal gas." Mar Chem., 2, 203-215.

                                                                            A13/A14 Tracers, CITHER-3

4. SURFACE pCO2 - WOCE SECTION A14
   (Aida F. Rios and Trinidad Relldn)
   Instituto de Investigaciones Marinas (IIM). Vigo. (CSIC)


4.1 CALCULATION AND LATITUDINAL VARIATION OF SURFACE pCO2

Surface pCO2 was calculated from alkalinity and pH15 using published equations 
for the oceanic carbon system (Mehrbach et al 1973; Weiss, 1974). Values are 
given in atm. Figure VII-11a shows the relationship between alkalinity and 
salinity at the surface. Two straight lines can be drawn with very good 
correlation coefficients, showing different slopes. For a given salinity, 
alkalinity is higher to the south (32S - 45S). Figure VII-11b represents the 
distribution of surface pCO2 along the track of the first leg of CITHER-3. The 
average partial pressure Of CO2 in the atmosphere given by Keeling et al (1995) 
for the year 1995 is 359 atm which is also represented by a thin line. 
Stations situated to the north of the Equator and to the south of 32 show 
surface pCO2 values lower than atmospheric. Between the Equator and 32S 
surface pCO2 is higher than atmospheric pCO2. Two domes can be observed, the 
highest centered just in the Tropic and the lowest around 5S. In general, 
surface pCO2 values were usually higher than the atmospheric along the section.

Figure VII-11c shows the relationship between pCO2 and temperature at the 
surface. Three straight lines can be observed: 

                    i)  between stations 67 and 97, 
                   ii)  between 23 and 43, and 
                  iii)  between 8 and 23. 

Theoretically, an in situ temperature increase of 12C causes a pCO2 increase 
of about 15 atm (Rios et al, 1995). Through the straight lines 67-97 and 
23-43, a temperature decrease of 12C produces a pCO2 decrease around 15 atm 
(12 and 16 atm respectively). The line 8-23 does not follow the same pattern. 
A temperature decrease of 1C causes a pCO2 increase of about 44 atm. This 
variation to the general pattern is due to the effect of biological processes 
which produces a pCO2 decrease. In this particular case a variation of 0.2 
mg/m3 in chlorophyll produces a pCO2 decrease of about 28 patm.


4.2 REFERENCES

Keeling, C.D., T.P. Whorf, M. Wahlen and J. van der Plicht, (1995) 
    "Interannual extremes in the rate of rise of atmospheric carbon dioxide 
    since 1980." Nature, 375, 666-670.

Mehrbach, C., C.H. Culberson, J.E. Hawley and R.M. Pytkowicz, (1973) 
    "Measurements of the apparent dissociation constant of carbonic acid in 
    seawater at atmospheric pressure." Limnol. Ocean., 18, 897-907.

Rios, A.F., T.R. Anderson and F.F. Prez, (1995) "The carbonic system 
    distribution and fluxes in the NE Atlantic during Spring 1991." Prog. 
    Oceanog., 35:293-312

Weiss, R.F., (1974) "Carbon dioxide in water and seawater: The solubility of a 
    non-ideal gas." Mar. Chem., 2, 203-215.



5. TOTAL ORGANIC CARBON - SECTION WOCE A14
   (Xos Antn Alvarez Salgado)
   Instituto de Investigaciones Marinas (IIM). CSIC. Vigo

                                                                            A13/A14 Tracers, CITHER-3

5.1. SAMPLING PROCEDURE

Selected samples for the determination of Total Organic Carbon (TOC) were 
taken at 10 depths in 6 stations along section WOCE A14. Pyrex(r) glass bottles 
(100 ml) were used. The bottles were sequentially washed thoroughly with 
diluted sodium hypochloride, 0.1N hydrochloric acid and, finally, with 
milli-Q(r) water. Samples were collected directly, after rinsing the bottles 
three times. Samples were immediately acidified to pH2 by adding 0.5 ml of a 
2.5N hydrochloric acid solution, covered up with parafilma below the top, and 
stored in the darkness until analysis in the laboratory. Acidification with 
HCI and storage in the cold is the most convenient and practical method for 
DOC preservation for long periods (Chen and Wangersky, 1996). Extremely low 
particulate organic carbon levels in open ocean waters prevented us to filter 
the samples, as contamination during filtration is one of the main sources of 
error in dissolved organic carbon (DOC) measurements.


5.2. EQUIPMENT AND METHODS

Samples were analysed in the laboratory by High Temperature Catalytic 
Oxidation (HTCO), with a commercial Shimadzu TOC-5000. The acidified samples 
were decarbonated by vigorous stirring with synthetic air for ~1/2 h, and 
injected directly onto a 0.5% platinum over alumina catalyst at 680C, under 
an atmosphere of high purity air. Quantitatively produced CO2 gas is measured 
using an NonDispersive Infra-Red (NDIR) detector and the resulting area 
estimated with a peak integrator. Three to 5 replicate injection of 200 ml 
were performed for each sample. As a typical injection cycle takes ~4 minutes, 
each sample requires between 12 and 20 minutes for completion.

Potassium Hydrogen Phthalate (KHP) was used for calibrating the system. A 
4-point calibration curve prepared in UV irradiated Milli-Q(r) water (range 
0-180 M-C) were performed every day. We spent 4 days to analyse the whole 
sample set. The corresponding calibration curves are presented in figure 
VII-12. The correlation coefficient (r 2) for the individual calibration 
curves was >0.9997. A single regression line was used for the whole set of 
calibration curves, being the slope 197.8 areaM-C-1 (C.V., 0.6%) and r 2 = 
0.9994. System blank (='instrurnent blank'+ DOC in UV-Milli-Q(r) water) was low 
and stable, 10.40.4  M-C (averageSD) for the whole set of blanks analysed. 
DOC concentration in UV-Milli-Q(r) water can be considered negligible.

DOC concentration in samples (DOCx) were calculated dividing the average area 
of the 3-5 replicate injections (Ax) by the slope of the average regression 
line (S) and subtracting the average system blank (BLANK):

                                     A X
                              DOCx = ---  -  BLANK
                                      S  

The average coefficient of variation (C.V.) of the peak area was -1%, ie. the 
average standard deviation (SD) was 0.8 M-C.
                                                                            A13/A14 Tracers, CITHER-3

5.3. TOC DISTRIBUTIONS

Figure VII-13 show the composite TOC profiles for the 6 stations occupied. TOC 
below 500 m was quite constant, 573 M, in spite of the dramatic changes in 
water masses composition and apparent oxygen utilisation (AOU) along section 
WOCE A14. A DOC excess in waters of the upper ocean (<500m) was observed, 
ranging from an average integrated value of 58 M-C (stn 106) in the 
Sub-Antarctic Zone (SAZ) to 74 M-C (stn 76) in the Subtropical Gyre. Maximum 
values, >90 M-C, were observed in the upper level (<100 m) of the Subtropical 
Gyre. Detailed profiles of the upper 1000m are presented in figure VII-14.

This values are in the same range of that obtained by Alvarez-Salgado (1995) 
in the Western South Atlantic and by Thomas et al (1995) in the Equatorial 
Atlantic ocean, using the same technique


5.4. REFERENCES

Alvarez-Salgado, (1996) "Total Organic Carbon Measurements." Campagne 
    CITHER-2. Recuiel de donnes. Volume 3: Traceurs Gochimiques, p. 73. Le 
    Groupe CITHER-2. Rapport Interne LPO (96-=2). pag. 73

Thomas C., G. Cauwet and J.-F. Minster, (1995) "Dissolved organic carbon in 
    the equatorial Atlantic Ocean." Mar. Chem, 49:155-169.

Chen W. and P.J. Wangersky, (1996) "Rates of microbial degradation of 
    dissolved organic carbon from phytoplankton cultures." J. Plank. Res., 
    18:1521-1533.


FIGURE LEGENDS (see pdf doc for figures)

Figure VII-1:  Results for pHsss and pHis at zero potential at each 
               calibration vs station.

Figure VII-2:  Results for pHsss at each station and pHsss corrected with the 
               pHis
       
Figure VII-3:  Distribution of pHsss (open squares), CRM (points), CRM 
               corrected with the SSS anomaly (open circles) and CRM corrected 
               with SSS and Culberson anomalies (diamonds)

Figure VII-4:  Variation of SSS alkalinity vs station.

Figure VII-5:  Alkalinity distribution of CRM (points), CRM corrected with the 
               Culberson anomaly (open circles) and CRM corrected with 
               Culberson and SSS anomalies (diamonds)

Figure VII-6:  Absolute difference of pH duplicate results versus: (a) station 
               number, (b) pressure; (c) frequency distribution (%).

Figure VII-7:  Absolute difference of Alkalinity results versus: (a) station 
               number, (b) pressure; (c) frequency distribution (%).

Figure VII-8:  Comparison of vertical distributions of alkalinity among 
               stations 43, 76, 88 (CITHER-3) and 75, 135, 209 (SAVE) 
               respectively, surveyed around the same geographical position.

Figure VII-9:  Comparison of vertical distributions of TIC among stations 43, 
               76, 88 (CITHER-3) and 75, 135, 209 (SAVE) respectively, 
               surveyed around the same geographical position.

Figure VII-10: Relationship between calculated and measured total inorganic 
               carbon during Section WOCE A14.

Figure VII-11: a) Relationship between alkalinity and salinity of surface 
               water; b) Distribution of surface pCO2 along the WOCE A14 
               section. The thin line at 359 is the atmospheric pCO2 for 1995 
               according to Keeling et al, (1995); c) Relationship between 
               pCO2 and in situ temperature.

Figure VII-12: Composite calibration curve from the 4 calibrations performed 
               during the analyses of TOC samples taken along section WOCE 
               A14.

Figure VII-13: Composite TOC profiles for the 6 stations occupied along 
               section WOCE A14.

Figure VII-14: Detailed TOC profiles of the upper 1000m for the 6 stations 
               occupied along section WOCE A14.



__________________________________________________________________________________________
__________________________________________________________________________________________



A13 CTD DATA QUALITY EVALUATION
(Robert C. Millard)
2001 NOV 29


The cruise track for WOCE section A13 is shown in Figure 1. It is a South to 
North section ending at 0E & 4.5N. The southerly extend of the section is 40S 
along first 9E and then jogging to 5E. The beginning position of every tenth 
station is indicated on figure 1. These data are plotted from the station 
summary file and validate the format and beginning positions data of this file. 
Three depth contours (0, 3000 and 5000 meters) are plotted from TBASE to help 
in identifying the deep basins water masses. Stations centered on 135 represent 
the Cape Basin while stations centered on 190 to 200 are taken in the Angola 
Basin and stations around 135 are taken in the Guinea Basin. 


FIGURE 1: Plot beginning station positions from summary file.


The CTD salinity and oxygen for the individual 2-decibar profiles are compared 
with one another and are also checked against the bottle file up cast CTD and 
water bottle salinity and oxygen values. Figure 2a is an over plot of all good 
CTD and bottle file salinities.  The solid lines are 2-decibar down casts while 
(o) are up cast CTD and (+) are bottle values.  A problem can be seen in the 2-
decibar salinity at the bottom of stations 119, 149, and 152. A closer 
examination of the 2-decibar station files shows that all three of these 
profiles are truncated at a depth shallower than the bottom depth indicated in 
the water sample file as follows: Station 119 truncated at 1622 decibars versus 
4913 decibars in the bottle file; station 149 truncated at 3830 decibars versus 
4899.7 decibars in the bottle file; and Station 152 truncated at 4794 decibars 
versus 4939 decibars in the bottle file. Except for this problem the CTD 
salinity data looks very good. Figure 2b is an expanded plot of salinity versus 
potential temperature in the deep water. The CTD profiles again look good as 
does the water sample salinities (+) except for occasional fresh bottle 
salinities.  Figure 3a shows an over plot of all good CTD and bottle file 
oxygen. As with salinity, a problem can be seen in oxygen at the bottom of the 
cast for stations 119, 149 and 152 in the 2-dbar station files. Except for this 
data truncation problem, the CTD oxygen data looks very good. Figure 3b is an 
expanded plot of oxygen versus potential temperature in the deep water. The CTD 
profiles look good as does the water sample oxygen values (+) except for some 
occasional high bottle oxygen values.


FIGURE 2a: Overall potential temperature versus salinity for all 2 decibar data 
           files plus all PI good bottle and CTD salinities from water sample 
           file.

FIGURE 2b: A plot of potential temperature versus salinity in the deep water for 
           all 2 decibar data files plus all PI good bottle and CTD salinities 
           from water sample file.  Water masses are denoted by Basin with the 
           Angola Basin indistinguishable from the Guinea Basin except no 
           Potential temperatures below 1.95 C.  The bottom salinity 
           progressively shifts fresh at the more southerly (lower) station 
           numbers.

                                                                            A13 CTD DQE

The 2-decibar salinity noise level for A13 was estimated by differencing the 
filtered salinity with wavelength of 24 decibar for a cut-off against the 
unfiltered salinity for profiles depths below 4000 decibars. Assuming the 
absence of deep salinity structure on scales less than 24 decibars at these 
depths, the standard deviation of the differences becomes an estimate of the 
salinity noise. The minimum RMS value across all stations (2nd value) is 
perhaps the better noise estimator.  An examination of the 2-decibar salinity 
noise estimate for the deep water for all CTD profile greater than 4000 
decibars shows an average RMS salinity noise across all stations of 0.00026 psu 
and a minimum salinity noise level of 0.00019 psu at station 207. This compares 
with values ranging from 0.00012 psu to 0.00047 psu for other WOCE cruises 
checked. A similar estimate across all 2-decibar oxygen noise level for all CTD 
profiles greater than 4000 decibars shows an average RMS oxygen noise level of 0.17 

FIGURE 3a: Overall plot of oxygen versus potential temperature.  Note the high 
           oxygen for station 119 at the bottom and low oxygen values for 
           stations 149 & 152.   These stations also have bad bottom salinity 
           values and appear to be truncated as noted earlier. 

FIGURE 3b: A deep-water plot of oxygen versus potential temperature.  The bottom 
           oxygen values are lower at the colder potential temperatures at the 
           south end of the section.

M/kg and a minimum oxygen noise level of 0.14 M/kg also at station 207. This 
compares with values ranging from 0.10 um/kg to 0.20 M/kg for other WOCE 
cruises examined.

A plot comparing the good up cast water sample salinities to the pressure 
interpolated salinity values from the 2 decibar down profiles are shown in 
Figure 4a-c. An increased scatter is observed in the salinity differences, 
particularly in the stronger vertical gradient region near the surface compared 
to up cast only comparisons shown next in Figure 5a-c. The lower panel plot 
(Figure 4c) is particularly useful in for verifying how well the bottle and 
downcast CTD salinity match particularly in the deep-water. Panel 4b shows the 
mean salinity difference below 1500 decibars (solid black curve) and indicates 
that the downcast 2 decibar CTD salinity generally match the deep bottles 
salts. Panel 5c plots the salinity differences versus pressure to check for any 
systematic vertical calibration variation in the CTD salinity. The CTD salinity 
below 5000 decibars seems to be less than the water sample salts. This slight 
systematic salinity offset is not obvious when looking at the deep-water 
Theta/S plot (Figure 2b).

FIGURES 4a, b, and c: PI "Good" water sample salinities & CTD down profile at 
           matching pressure levels.  The lower panel versus pressure indicates 
           that the 2 decibar down profile salinities are generally well matched 
           to the water sample salts except the below 5000 decibars where the 
           bottle salts are higher.

FIGURES 5a, b, and c: Good water sample & CTD salinity data (PI) from up profile 
           water sample data file.

                                                                            A13 CTD DQE

The upper panel of Figure 5 is the difference of all good water samples and 
represents 85.5% of all bottle salts. All of the CTD salinities are flagged as 
good in the water sample file. The maximum good water sample salinity 
difference Ds= (CTD-WS) seen in Figure 5a never exceeds Ds=0.008 psu which is 
pretty stringent. The center panel plots the mean salt for P>1500 decibars 
(black line) and shows that CTD salinity is well matched to water sample salts 
deep with a tight standard deviation of 0.0018 psu across all stations. The 
lower panel suggests that up cast CTD salts are systematically low compared to 
the bottle salts below 5000 decibars, as seen in earlier in Figure 4c for down 
profile comparisons.  The salt differences histograms are plotted for various 
depth intervals in figure 6 together with the mean and standard deviation. 
Between 3000 & 4500 decibars the mean is +0.0005 psu while below 4500 decibars 
the mean difference is -0.0006 psu.  


FIGURE 6:  Histograms of Salinity difference Ds= (CTD -WS) for various pressure 
           intervals.  The mean salinity and the standard deviation of  Ds show 
           little variation in the vertical.

FIGURES 7a, b, & c:  Good water sample & CTD oxygen data (PI QC) from up profile 
           water sample data file.  Center panel is for pressures greater than 
           1500 decibars and shows a good match of CTD to Bottle oxygens with a 
           low standard deviation of 1.2 Um/kg.  The lower panel shows the CTD 
           oxygen to be well matched to bottle values at all depths.

The upper panel of Figure 7 comprises the difference of all good water sample 
oxygen values. This represents 88% of the total number of bottle oxygen values. 
All of the CTD oxygen values are flagged as good in the water sample file. The 
maximum good water sample oxygen difference Dox= (CTD-WS) seen in Figure 7a 
never exceeds Dox=7.2 M/kg. The center panel plots the mean oxygen difference 
for P>1500 decibars (black line) and shows that CTD oxygen is very well matched 
to water sample oxygen values in the deep water with a tight standard deviation 
equal to 1.2 M/kg across all stations. The lower panel suggests that up cast 
CTD oxygen is well matched at all depths. The oxygen difference histograms are 
plotted for various depth intervals in Figure 9 together with the mean and 
standard deviation. The CTD oxygen at all depth levels are well matched to 
bottle values. 


FIGURE 8:  Histograms of Oxygen difference Dox = (CTD -WS) at various pressure 
           intervals.  The mean oxygen difference and the standard deviation of  
           Dox show little variation in the vertical. 

FIGURE 9a: Salinity versus Potential Temperature for intersecting East/West WOCE 
           sections to A07.  Water sample salinity A07 is closely matched to A13.

FIGURE 9b: Salinity versus Potential Temperature for intersecting East/West 
           sections to A08.  The water sample salinity A07 closely matches A13.
      
FIGURE 9c: Salinity versus Potential Temperature for intersecting  East/West 
           WOCE section to A10.  The water sample salinity A10 is slightly 
           fresher than A13.

                                                                            A13 CTD DQE

COMPARISON OF INTERSECTING WOCE SECTIONS

To check and validity the consistency of WOCE line A13, bottle salinity and 
oxygen data from 3 intersecting WOCE cruises A07, A08, and A10 are compared 
with corresponding A13 stations at cross over stations at 4.5 S, 11.3S and 30S. 

A comparison of the water sample salinities values for A07, A08 and A10 (black 
squares) against stations of WOCE line A13 at corresponding geographic 
locations, see Figures 9 a- c, indicates a close match of the water sample 
salts of these three intersecting WOCE lines to both the bottle and CTD 
salinities of section A13.

FIGURE 10a: Oxygen versus Potential Temperature for intersecting East/West WOCE 
            section A07 (4.5 S), compared with A13. 

FIGURE 10b: Oxygen versus Potential Temperature for intersecting East/West WOCE 
            section A08 (11.3 S) compared with A13.  The bottle oxygen values of 
            A08 are not well matched to A13.  A08 bottle oxygen values need to 
            be checked. 

FIGURE 10c: Oxygen versus Potential Temperature for intersecting East/West WOCE 
            section A10 (30 S) compared with A13. 

FIGURE 11:  Plot of density instabilities < -0.01 kg/m3/dbars (+) and < -0.0075 
            kg/m3/dbars (x) versus pressure and station number where they occur.

The water sample oxygen values for A07 and A10 closely also match the bottle 
and CTD oxygen values of A13 at section crossover. The oxygen values of A08 are 
systematically lower than the corresponding A13 oxygen values by roughly 15 
mU/kg. The oxygen values of A13 appear to be fine suggesting that the water 
sample oxygen values of A08 need to be examined further.

The list below is the density instabilities shown in Figure 11. Most of the 
density inversions are in the upper water column in regions of higher 
temperature gradient and likely due to temperature and conductivity sensor 
lagging mismatches. Stations 119, 149, and 152 have deeper density inversions 
associated with bad salts at the bottom of the cast mentioned earlier. 

                                                                            A13 CTD DQE

                         Dsg/dp =  -0.01  kg/m3/dbar
 
                         Dsg/dp      Sta#     P_dbar  Salinity 
                        -0.0147       111        48   35.2428  
                        -0.0179       111        52   35.2237  
                        -0.0117       111        64   35.1533  
                        -0.0113       114       308   34.8729  
                        -0.0125       117       326   34.9965  
                        -0.2400       119      1620   34.6522  % bad data @ bottom
                        -0.0207       122        68   35.5024  
                        -0.0178       122        72   35.4875  
                        -0.0229       122        74   35.4464  
                        -0.0101       129       282   34.8203  
                        -0.0108       134       136   35.3534  
                        -0.0103       134       438   34.8989  
                        -0.0105       136       248   35.2364  
                        -0.0101       136       846   34.4397  
                        -0.0293       139       234   35.0278  
                        -0.0100       140       560   34.5439  
                        -0.0106       140      1088   34.4644  
                        -0.0113       148       326   35.1440  
                       -13.9610       149      3828   34.8212  % bad data @ bottom 
                       -13.8598       152      4794   34.7376  % bad data @ bottom 
                        -0.0146       153        68   35.6983  
                        -0.0111       153        72   35.5618  
                        -0.0184       153        78   35.4689  
                        -0.0103       156       352   34.8731  
                        -0.0102       156       504   34.5653  
                        -0.0126       157       394   34.8061  
                        -0.0106       160        84   35.4609  
                        -0.0199       161        74   35.3674  
                        -0.0123       172       172   35.1868  
                        -0.0104       177       188   35.1496  
                        -0.0111       179        72   35.5785  
                        -0.0141       179        80   35.5639  
                        -0.0156       180        98   35.7891  
                        -0.0185       180       114   35.5472  
                        -0.0136       185        80   35.6958  
                        -0.0121       192        56   35.8663  
                        -0.0105       200        72   35.5214  
                        -0.0166       215        58   36.0456  
                        -0.0163       223       670   34.5188  
                        -0.0236       231       102   35.7615  
                        -0.0116       234        64   35.9565  
                        -0.0157       236       104   35.8332  
                        -0.0155       237       100   35.8587  
                        -0.0229       238       106   35.7791  

                                                                            A13 CTD DQE

                         Dsg/dp =  -0.0075  kg/m3/dbar
 
                         Dsg/dp       Sta#    P_dbar  Salinity
                        -0.0077       109        68   35.2168  
                        -0.0098       109       144   35.0324  
                        -0.0147       111        48   35.2428  
                        -0.0179       111        52   35.2237  
                        -0.0117       111        64   35.1533  
                        -0.0097       111        66   35.0061  
                        -0.0080       113        66   35.2707  
                        -0.0091       113        76   35.1572  
                        -0.0113       114       308   34.8729  
                        -0.0097       115       228   35.1364  
                        -0.0076       116       226   35.1722  
                        -0.0125       117       326   34.9965  
                        -0.0080       118       122   35.3688  
                        -0.0089       118       130   35.3135  
                        -0.2400       119      1620   34.6522  
                        -0.0076       120        50   34.8386  
                        -0.0082       120        88   34.7976  
                        -0.0207       122        68   35.5024  
                        -0.0178       122        72   35.4875  
                        -0.0229       122        74   35.4464  
                        -0.0095       122        88   35.4605  
                        -0.0085       122       274   35.0695  
                        -0.0093       126        70   34.7239  
                        -0.0101       129       282   34.8203  
                        -0.0094       129       304   34.7773  
                        -0.0077       130       244   34.8463  
                        -0.0096       130       934   34.3226  
                        -0.0090       131       164   35.0051  
                        -0.0100       133        98   35.3841  
                        -0.0091       133      1090   34.3394  
                        -0.0108       134       136   35.3534  
                        -0.0082       134       156   35.2019  
                        -0.0103       134       438   34.8989  
                        -0.0082       136       202   35.3601  
                        -0.0105       136       248   35.2364  
                        -0.0077       136       408   35.0172  
                        -0.0101       136       846   34.4397  
                        -0.0075       136       912   34.3540  
                        -0.0089       137       378   35.1469  
                        -0.0083       138       908   34.4194  
                        -0.0081       139       176   35.0405  
                        -0.0293       139       234   35.0278  
                        -0.0084       139       448   34.7131  
                        -0.0076       139      1016   34.4189  
                        -0.0100       140       560   34.5439  
                        -0.0106       140      1088   34.4644  
                        -0.0113       148       326   35.1440  
                       -13.9610       149      3828   34.8212  
                       -13.8598       152      4794   34.7376  
                        -0.0146       153        68   35.6983  
                        -0.0111       153        72   35.5618  
                        -0.0184       153        78   35.4689  
                        -0.0095       154       474   34.6947  
                        -0.0081       155       160   35.2073  

                                                                            A13 CTD DQE

                         Dsg/dp =  -0.0075  kg/m3/dbar  continued
 
                         Dsg/dp       Sta     P_dbar  Salinity 
                        -0.0103       156       352   34.8731  
                        -0.0102       156       504   34.5653  
                        -0.0076       156       590   34.4513  
                        -0.0126       157       394   34.8061  
                        -0.0083       159       270   35.0442  
                        -0.0099       159       562   34.4628  
                        -0.0092       160       362   34.7609  
                        -0.0106       160        84   35.4609  
                        -0.0079       161       144   35.2007  
                        -0.0084       161       214   35.0951  
                        -0.0090       161       360   34.7456  
                        -0.0199       161        74   35.3674  
                        -0.0080       162       138   35.1505  
                        -0.0077       162       296   34.8309  
                        -0.0079       162       306   34.8009  
                        -0.0076       165       258   34.9908  
                        -0.0089       169       136   35.2265  
                        -0.0095       171       226   35.0225  
                        -0.0123       172       172   35.1868  
                        -0.0084       175        82   35.6220  
                        -0.0104       177       188   35.1496  
                        -0.0111       179        72   35.5785  
                        -0.0141       179        80   35.5639  
                        -0.0089       180        58   35.7218  
                        -0.0156       180        98   35.7891  
                        -0.0185       180       114   35.5472  
                        -0.0091       181       134   35.3506  
                        -0.0078       183       162   35.2063  
                        -0.0090       183       170   35.1308  
                        -0.0081       183       270   34.9900  
                        -0.0076       185        68   35.7691  
                        -0.0136       185        80   35.6958  
                        -0.0076       187       236   35.0396  
                        -0.0121       192        56   35.8663  
                        -0.0078       193       104   35.4455  
                        -0.0097       194        94   35.4412  
                        -0.0099       200        62   35.5723  
                        -0.0105       200        72   35.5214  
                        -0.0096       207         8   35.7782  
                        -0.0166       215        58   36.0456  
                        -0.0085       217       298   35.0102  
                        -0.0078       217       426   34.7100  
                        -0.0083       218       320   34.9524  
                        -0.0163       223       670   34.5188  
                        -0.0089       228       268   35.2256  
                        -0.0236       231       102   35.7615  
                        -0.0116       234        64   35.9565  
                        -0.0157       236       104   35.8332  
                        -0.0155       237       100   35.8587  
                        -0.0229       238       106   35.7791  
 
BOTTLE FILE SALINITY & OXYGEN DQE 2ND QUALITY WORD CHANGES

The A13 water sample data file A13hy.txt CTD and bottle salinity and oxygen 
values were screened and a 2nd DQE quality word (Q2) appended reflecting 
changes to the PI Quality check (Q1). The following criteria was used to test 
the validity of the water sample salinity and oxygen values: for pressures less 
than 1000 decibars "bad" data with a Ds<0.004 psu or Dox < 4.3 Um/kg is flagged 
as "good" in Q2. . A test of "good" Q1 Ds>.1 psu at pressure less than 1000 
decibars does not flag any "questionable" salinity data in Q2 as no Ds exceeds 
0.008 psu at any depth as was shown in the upper panel of figure 5.  For 
pressures greater than 1000 decibars, "good" bottle salinities with a Ds>0.007 
psu (3.8 standard deviations) or oxygen differences Dox>4.3 Um/kg are flagged 
as "questionable" along with the CTD salinity in Q2. Scans in the water sample 
data file where the 2nd quality word Q2 does not match the PI's Q1 follow:

                                                                            A13 CTD DQE

SALINITY CHANGES:

Changed WS Salts flags ds< 0.004& pw<1000 or ds> 0.007 for pw >1000 decibars 


STN  CAST  SAMP  BTL CTDPRS   CTDTMP   CTDSAL  CTDOXY  THETA  SALNTY  OXYGEN  Q1     Q2 
                 ***                  *******  ******         ******* ******* *
120   1     5    28  2795.7   2.3230  34.8460  226.0   2.1080 34.8380  225.9  22222 23232
120   1     9    24  3594.2   1.6800  34.7980  222.0   1.3990 34.7910  221.9  22222 23232
121   1     3    30   122.6  13.2320  35.0110  240.8  13.2150 35.0150  238.3  22232 22222
122   1     3    30   121.4  15.3810  35.4280  221.1  15.3620 35.4240  222.1  22232 22222
127   1     7    26   494.4  10.8800  34.9210  263.4  10.8190 34.9170  255.8  22233 22223
133   1     4    29   121.1  13.9520  35.1030  242.3  13.9350 35.1070  239.1  22232 22222
140   1     5    28   196.4  13.8890  35.2010  224.5  13.8610 35.2050  227.9  22232 22222
141   1     1    32     5.4  21.2840  35.7900  230.4  21.2830 35.7940  224.7  22233 22223
142   1     1    32     4.1  21.7290  35.7540  218.1  21.7280 35.7570  223.4  22233 22223
143   1     3    30   122.1  15.9750  35.5120  225.2  15.9560 35.5080  227.0  22232 22222
144   1     1    32     4.2  21.5760  35.7440  222.1  21.5750 35.7480  223.5  22232 22222
144   1     9    24   995.5   4.0240  34.3640  210.2   3.9490 34.3600  200.2  22233 22223
145   1     1    32     4.1  21.5050  35.7530  220.9  21.5040 35.7570  223.2  22232 22222
145   1     8    25   885.1   4.6070  34.3160  223.2   4.5370 34.3200  220.8  22232 22222
147   1     25    8  3996.8   1.5300  34.7790  220.9   1.2100 34.7720  220.6  22222 23232
150   1     31    2  4875.3   1.1470  34.7370  216.3    .7390 34.7300  216.1  22222 23232
168   1     1    26     3.7  22.8560  35.5570  225.4  22.8550 35.5600  216.7  22233 22223
185   1     5    28   395.2   8.3750  34.7500   42.9   8.3340 34.7460   43.4  22232 22222
216   1     1    32     4.7  29.5650  34.8260  208.1  29.5640 34.8290  207.5  22232 22222
224   1     2    31    46.6  24.8480  36.2590  186.5  24.8380 36.2550  195.1  22233 22223
227   1     25    8  4195.8   2.3090  34.8830  242.1   1.9440 34.8760  241.3  22222 23232
229   1     1    32     5.5  29.4240  34.1220  199.2  29.4230 34.1260  196.1  22232 22222
238   1     1    32     5.9  29.3890  34.6940  194.2  29.3880 34.6980  195.8  22232 22222   

OXYGEN CHANGES:

Changed WS oxygen flags dox< 4.2 & pw< 1000 or  dox   > 4.2 for pw >1000 decibars 


                                                                            A13 CTD DQE


STN  CAST  SAMP  BTL CTDPRS   CTDTMP   CTDSAL  CTDOXY  THETA  SALNTY  OXYGEN  Q1     Q2 
                 ***                  *******  ******         ******* ******* *
118   1     18   15  2396.1   2.5120  34.8370  221.3   2.3310  -9.0000  227.7  22292 22293
124   1      4   29   121.0  15.3330  35.3940  220.8  15.3140  35.3890  224.8  22233 22232
124   1     22   11  3195.7   2.2900  34.8500  229.2   2.0350  -9.0000  235.5  22292 22293
125   1      3   30   120.6  14.9300  35.3400  218.2  14.9120  35.3480  221.9  22233 22232
126   1      3   30   120.9  14.0490  35.1780  230.3  14.0320  34.9030  234.4  22233 22232
127   1      1   32     3.5  16.4360  34.9660  249.4  16.4350  34.9660  253.6  22223 22222
128   1      3   30   120.9  12.0350  35.0850  245.5  12.0190  35.0840  249.4  22223 22222
130   1      7   26   395.7   8.6910  34.5990  231.2   8.6490  34.6050  227.3  22233 22232
131   1      1   32     3.8  16.3350  34.8150  258.5  16.3340  34.8150  254.4  22223 22222
132   1      8   25   895.0   3.8470  34.2870  231.6   3.7810  34.2870  227.7  22223 22222
135   1      5   28   295.3  13.6530  35.2130  214.7  13.6110  35.1990  218.3  22233 22232
136   1      8   25   796.6   5.8010  34.3990  209.9   5.7310  34.3990  213.4  22223 22222
137   1      9   24   995.0   4.3520  34.3770  210.0   4.2740  34.3760  205.9  22223 22222
137   1     28    5  4601.7   1.1570  34.7430  218.2    .7810  -9.0000  223.8  22292 22293
141   1      2   31    46.0  21.0500  35.7410  229.7  21.0410  35.7330  225.9  22233 22232
151   1      3   30    46.1  21.7090  35.6730  227.3  21.7000  35.6660  223.4  22233 22232
152   1      4   29   196.1  14.1250  35.2380  212.1  14.0960  35.2500  215.9  22233 22232
152   1     20   13  2998.7   2.3880  34.8610  231.8   2.1510  -9.0000  238.0  22292 22293
164   1      4   29   196.7  11.8450  35.0130  182.5  11.8200  35.0080  186.7  22233 22232
170   1      9    8   595.6   5.1970  34.4410  145.2   5.1480  34.4390  149.0  22223 22222
181   1      2   31    46.5  22.1280  35.7070  236.0  22.1190  35.7480  238.4  22233 22232
185   1      1   32     5.6  24.9480  36.2680  206.3  24.9470  36.2650  210.5  22223 22222
186   1      7   26   595.2   5.9290  34.5400   85.9   5.8770  34.5400   90.0  22223 22222
191   1      7   26   795.1   4.7960  34.4990  106.6   4.7320  34.4980  110.3  22223 22222
193   1      4   29   196.1  11.3740  35.0910   32.2  11.3490  35.0930   36.3  22223 22222
193   1     28    5  4798.2   2.3830  34.8830  233.7   1.9430  -9.0000  240.8  22292 22293
194   1     15   18   426.1   8.1120  34.7380   42.3   8.0680  34.7360   46.3  22223 22222
194   1     29    4   855.5   4.4790  34.5080  123.1   4.4120  34.5110  126.8  22223 22222
196   1     27    6  4796.0   2.3750  34.8820  234.4   1.9350  -9.0000  241.4  22292 22293
197   1      7   26   795.4   4.7580  34.5130  105.3   4.6940  34.5120  109.3  22223 22222
200   1      1   32     5.0  28.5290  36.1600  193.7  28.5280  36.1640  197.1  22223 22222
200   1      7   26   595.7   6.3630  34.5960   48.8   6.3090  34.5950   52.4  22223 22222
203   1     25    8  4396.1   2.3310  34.8840  233.4   1.9410  -9.0000  240.4  22292 22293
208   1      1   32     4.6  29.2390  35.8170  192.7  29.2380  35.8160  196.1  22223 22222
208   1      5   28   295.2  11.5970  35.1150   56.1  11.5590  35.1160   52.0  22223 22222
212   1      4   29   196.8  14.3390  35.4490   98.0  14.3100  -9.0000   95.7  22293 22292
212   1     11   22  1395.7   4.1160  34.8970  208.3   4.0040  34.8980  204.0  22222 22223
213   1      6   27   444.8   7.7770  34.7070   71.0   7.7320  34.6990   74.8  22233 22232
213   1     28    5  4397.0   2.3190  34.8830  232.4   1.9300  -9.0000  239.1  22292 22293
214   1      1   32     4.3  29.6210  34.9820  215.7  29.6200  34.9840  219.8  22223 22222
214   1      4   29   195.7  14.6810  35.5000  103.5  14.6520  35.4910   99.7  22233 22232
216   1      4   29   196.7  15.0220  35.5430  112.5  14.9920  35.5490  108.8  22233 22232
217   1      1   25     3.4  29.7150  34.8010  220.8  29.7140  34.7940  225.0  22233 22232
218   1     11   22   394.9   8.3070  34.7540   80.1   8.2660  34.7570   83.4  22223 22222
219   1      9   24   396.1   8.2720  34.7540   80.6   8.2310  34.7500   84.2  22223 22222
220   1      3   24   121.4  15.5300  35.6090  142.5  15.5110  35.6010  146.4  22233 22232
220   1      6   21   394.8   8.6900  34.7980   72.0   8.6480  34.7960   75.2  22223 22222
221   1      4   29   196.0  14.4880  35.4990  128.6  14.4590  35.5210  124.4  22233 22232
222   1     13   20  1395.4   4.3500  34.9360  214.3   4.2360  -9.0000  220.9  22292 22293
224   1      9   24   795.1   4.9360  34.5090  136.7   4.8710  34.5090  140.7  22223 22222
225   1      3   30    96.4  18.5240  35.9590  161.8  18.5070  35.9080  165.9  22233 22232
227   1      2   31    46.7  24.2710  36.1710  189.5  24.2610  36.1900  193.0  22233 22232
227   1      3   30   121.1  16.1080  35.6490  141.9  16.0890  35.6400  145.5  22233 22232
228   1      4   29   122.5  16.0330  35.6550  145.7  16.0140  35.6520  149.8  22223 22222
229   1      5   28   295.1  10.0350  34.9650   55.2  10.0010  34.9600   58.9  22223 22222
229   1     22   11  3595.8   2.4220  34.8960  240.4   2.1210  -9.0000  247.1  22292 22293
230   1      3   30   121.7  16.1400  35.6800  140.0  16.1210  35.6790  143.2  22223 22222
230   1     28    5  4598.3   2.2130  34.8710  238.8   1.8030  -9.0000  244.3  22292 22293
231   1     12   21  1594.5   4.0180  34.9590  234.2   3.8890  34.9600  229.8  22222 22223



__________________________________________________________________________________________
__________________________________________________________________________________________



A14 CTD DATA QUALITY EVALUATION
(Robert C. Millard)
2001 DEC 10


The cruise track of WOCE section A14 is a North to South section nominally 
along 9W between 4N and 45 S as shown in figure 1 with station positions. The 
position data is from the station summary file and thus checks the format and 
beginning stations positions contained in this file. Three depth contours (0, 
3000 and 5000 meters) are shown from TBASE to help with the deepwater mass 
identification by basin. The Angola Basin was crossed between stations 8 and 16 
while stations centered between 55 and 65 are around the Guinea Basin.  


FIGURE 1: Plot beginning station positions from summary file with every tenth 
          station annotated. 


The CTD salinity and oxygen data of the individual 2-decibar profiles are 
compared with one another and are also compared to the "good" up cast bottle 
file water sample and CTD salinity and oxygen data. Figure 2a is an over plot 
of all good PI CTD and bottle file salinities. The solid lines are 2-decibar 
down casts while circles (o) represent up cast CTD and (+) are bottle 
salinities. The 2-decibar CTD salinity data appears consistent among profiles 
and look good when compared with water sample values. Figure 2b is an expanded 
plot of salinity versus potential temperature in the deep water. Again, the CTD 
salinity looks consistent between profiles and well matched to the water sample 
salinities (+) except for an occasional fresh bottle salinity.  Figure 3a shows 
an overall plot of good CTD and bottle file oxygen data. A problem can be seen 
with the 2-decibar oxygen values near the surface for stations 22, 73 and 101. 
The near surface CTD oxygen values are anomalously high compared to neighboring 
stations and also exceed the oxygen saturation value and thus should be flagged 
as questionable in the 2-decibar and bottle files. Except for these few 
questionable surface oxygen values, the CTD oxygen data appear to be well 
calibrated to the bottle oxygen values. Figure 3b is an expanded plot of oxygen 
versus potential temperature in the deep water. The CTD oxygen appears to be 
well calibrated to each other and the bottle oxygen values (+) except for a few 
high bottle oxygen values in the deepwater.


FIGURE 2a: An overall potential temperature versus salinity plot displaying all 
           2-decibar data plus all PI good bottle and CTD salinities from water 
           sample file. 

FIGURE 2b: A deep-water plot of salinity versus potential temperature.  The 
           bottom salinity progressively shifts fresher for the more southerly 
           (higher) station numbers.

                                                                            A14 CTD DQE

The 2-decibar salinity noise is estimated by differencing the filtered salinity 
with a cut-off wavelength of 24 decibars from the unfiltered salinity at depths 
below 4000 decibars. Assuming the absence of deep salinity structure on scales 
less than 24 decibars at these depths, the standard deviation of the 
differences becomes an estimate of the salinity noise. The minimum RMS salinity 
difference for all stations greater than 4000 decibars is the second value 
given and is perhaps a better noise estimator provided the same instrument, in 
good working condition, was used throughout the cruise. The average RMS 
salinity noise for all deep (4000 decibar) stations is 0.00033 psu with a 
minimum salinity noise estimate of 0.00026 psu at station 13. These RMS 
salinity noise estimates are a little high when compared with values ranging 
from 0.00012 psu to 0.00047 psu for other WOCE cruises examined. A similar RMS 
estimate across all 2-decibar oxygen profiles greater than 4000 decibars shows 
an average RMS oxygen noise level of 0.20 uM/kg and a minimum oxygen noise 
estimate of 0.12 uM/kg again at station 13. This compares with values ranging 
from 0.10 um/kg to 0.20 uM/kg for other WOCE cruises examined.


FIGURE 3a: Overall plot of oxygen versus potential temperature.  Note oxygen 
           values greater than 290 uM/kg are found at stations 22, 73 and 101.   
           These stations have bottle oxygen values incorrectly flagged as 
           questionable in the bottle file while CTD oxygen is flagged as 
           "good".  These scans are identified with (%) in file A14.chg, 

FIGURE 3b: A deep-water plot of oxygen versus potential temperature.  Note the 
           variation of bottom oxygen values are progressively lower at the 
           higher station numbers progressing towards the south corresponding to 
           the salinity in figure 2b.

FIGURE 4a, b, & c:  Only the "Good" water sample salinities flagged by PI & CTD 
           down profile at matching pressure levels.  The lower panel versus 
           pressure indicates that the 2 decibar down profile salinities are 
           well matched to the water sample salts.  


Plots comparing the difference of the "good" up cast water sample salinities 
and the pressure interpolated 2-decibar down profile salinities are shown in 
figure 4a-c. An increased scatter is observed in the salinity differences 
(figure 4c), particularly in the stronger vertical gradient region near the 
surface when compared to up cast only comparisons shown in figure 5c. The lower 
panel, figure 4c, is particularly useful in for verifying how well the bottle 
and downcast CTD salinity match over the water column.  Panel 4b shows the mean 
salinity difference below 1500 decibars (solid black curve) and indicates that 
the down cast 2-decibar CTD salinity is well matched to the deep bottles salts 
across all stations. Panel 5c plots the salinity differences versus pressure 
checks for any systematic vertical calibration variation in the CTD salinity 
and verifies the CTD salts to be well matched in the vertical. The up cast 
bottle file CTD salinities in figure 5b seems to indicate a discrepancy between 
CTD & bottle salts for stations 87 through 103 with the CTD salinity slightly 
larger than the bottle salts.


FIGURE 5 a, b, & c:  Good up cast water sample & CTD salinity data (PI) from 
           water sample data file.  Center panel (P>1500 decibars) indicates 
           that CTD salinity is high when compared to the water sample salts for 
           stations 87 through 103. 

                                                                            A14 CTD DQE

The upper panel of figure 5 is the difference of all good water samples and 
represents 89.5% of all bottle salts. All of the CTD salinities are flagged as 
good in the water sample file. The maximum good water sample salinity 
difference Ds= (CTD-WS) seen in figure 5a never exceeds Ds=0.007 psu which 
makes the CTD & bottle salts very closely matched. The center panel plots the 
mean salt for P>1500 decibars (black line) and shows that CTD salinity is well 
matched to water sample salts deep with a tight standard deviation of 0.0019 
psu across all stations. The lower panel suggests that up cast CTD salts are 
also well matched to the bottle salts in the vertical. 

To further examine the differences between CTD and the up cast bottle 
salinities for stations 87 to 103, plots of salinity versus potential 
temperature for groups of 5 to 7 stations are shown in figures 6 a, b & c. The 
water sample salinities (+) are typically observed to be fresh with respect to 
both the 2-decibar down cast CTD salinities and the up cast bottle file 
salinities (o) for near all stations 87 to 103 and indicate that the 2-decibar 
down cast salinities may need further calibration work. 


FIGURE 6 a, b, & c:  Salinity versus potential temperature for 2 decibar CTD 
           down profiles with bottle (+)  & up cast CTD salinity (o).  The up 
           and down cast CTD salinity values match while the bottle (+) salts 
           are fresher than either CTD salt.  Figure 7 a, b, & c:  Good water 
           sample & CTD oxygen data (PI) from up profile water sample data file.  
           Center panel (P>1500 decibars) good match of CTD to bottle oxygen 
           values with a low standard deviation of 1.2 Um/kg.  The lower panel 
           shows the CTD oxygen to be well matched to bottle values at all depths.


The upper panel of figure 7 is the difference of all good water sample oxygen 
values compared to the bottle file CTD oxygen. The good water sample oxygen 
values represent 89.7% of the total number of bottle oxygen values collected. 
All CTD oxygen values are flagged as good or missing (there are two missing 
values = 9) in the water sample file. The maximum good water sample oxygen 
difference Dox= (CTD-WS) seen in figure 7a does not exceed Dox=7.8 uM/kg. The 
center panel plots the mean oxygen difference for P>1500 decibars (black line) 
and shows that CTD oxygen is very well matched to water sample oxygen values 
across all stations in the deep water with a tight standard deviation equal to 
1.2 uM/kg. The lower panel suggests that up cast CTD oxygen matches the bottle 
oxygen values well at all depths. A problem was noted earlier (figure 3a) with 
the near surface 2-decibar oxygen values for stations 22, 73 and 101. Plots of 
oxygen versus pressure for stations 22, 73, & 101 along with adjacent oxygen 
profiles are shown in figures 8a, b, & c. These three stations show excessive 
near surface oxygen values when compared to neighboring stations and the 
surface oxygen was also found to exceed oxygen saturation. These CTD oxygen 
data need to be flagged as questionable in both the 2-decibar and bottle files.


FIGURE 8 a, b, & c: Plots of high near surface oxygen values for stations 22, 
           73, & 101 compared with neighboring stations (noted earlier on figure 
           3a).  The surface oxygen values of these stations exceed the 
           saturation value and these oxygen values should be flagged as 
           questionable.

                                                                            A14 CTD DQE

COMPARISON OF INTERSECTING WOCE SECTIONS

To check and validate the salinity and oxygen data from WOCE line A14 against 
other WOCE sections, bottle salinity and oxygen data from 3 intersecting WOCE 
cruises A07, A08, and A10 are compared with corresponding A14 stations along 9W 
at crossover stations found around latitudes 4.5 S, 11.3S and 30S. A comparison 
of the water sample salinities of WOCE lines A07, A08 and A10 (black squares) 
are plotted along with neighboring stations of WOCE line A14 at corresponding 
geographic locations in figure 9a, 9b and 9c. The water sample salinities 
values for A07 and A10 closely match the bottle and CTD salinities values of at 
section crossovers with A14. The salinities values of A08 are systematically 
lower than the corresponding A14 salinities values by approximately 0.002 psu. 
These changes maybe due to a spatial shift as there are N-S salinity variations 
observed in A14.              


FIGURE 9 a, b, & c: Salinity versus Potential Temperature for 3 intersecting 
           East/West sections to A14.  Water sample salinity from intersecting 
           WOCE lines (black squares) are closely matched to A14.

FIGURE 10 a, b, & c: Oxygen versus Potential Temperature for 3 intersecting 
           East/West WOCE sections, A07 (4.5 S), A08 (11.3 S), & A10 (30 S) 
           compared with A14. 


COMPARISONS OF INTERSECTING WOCE SECTIONS FOR OXYGEN 

The oxygen data from three intersecting WOCE sections, A07 (4.5 S), A08 (11.3 
S), and A10 (30 S) are compared at crossover stations on WOCE line A14. The 
water sample oxygen values for A07 and A10 closely match the bottle and CTD 
oxygen values of A14 to better than 2 uM/kg as can be seen in the theta/oxygen 
plots of figures 10a and 10b. The oxygen values of A08 are systematically lower 
than the corresponding A14 oxygen values with an average difference of 18 mU/kg 
as seen in figure 10c.

                                                                            A14 CTD DQE

STABILITY TESTS 

A list of the density instabilities is displayed in Figure 11 with a listing also 
given below. All of the density inversions are in the upper water column in regions 
of higher temperature gradient and could well be due to sensor lag mismatches 
between temperature and conductivity. The number of questionable observations 
in the listing is modest compared to other cruises examined. 


FIGURE 11: Plot of density instabilities < -0.01 kg/m3/dbars (+) and < -0.0075 
           kg/m3/dbars (x) versus pressure and station number where they occur.


                    Dsg/dp =  -0.01  kg/m3/dbar
 
                  Dsg/dp       Sta#    P_dbar  Salinity 
                 -0.0108         3       296   35.0970  
                 -0.0110        11       122   35.4330  
                 -0.0114        38       214   35.0410  
                 -0.0124        46       286   35.0420  
                 -0.0119        77       776   34.4810  

                      Dsg/dp =  -0.0075  kg/m3/dbar
 
                  Dsg/dp       Sta#    P_dbar  Salinity 
                 -0.0075         2         4   35.0220  
                 -0.0108         3       296   35.0970  
                 -0.0110        11       122   35.4330  
                 -0.0095        23       100   35.3790  
                 -0.0081        29       182   35.0840  
                 -0.0082        31       186   35.1070  
                 -0.0114        38       214   35.0410  
                 -0.0096        43       282   34.9380  
                 -0.0077        45       224   35.1950  
                 -0.0082        46       234   35.1620  
                 -0.0124        46       286   35.0420  
                 -0.0081        47       260   35.0650  
                 -0.0076        47       338   34.8330  
                 -0.0085        48       238   35.1130  
                 -0.0097        52       250   35.1260  
                 -0.0091        56       272   35.0920  
                 -0.0075        56       596   34.4600  
                 -0.0081        58       304   35.0460  
                 -0.0119        77       776   34.4810  
                 -0.0092        77       932   34.3360  
                 -0.0079        79       208   35.7150  
                 -0.0097       102       344   34.2360  
                 -0.0090       105       384   34.2520  
                 -0.0084       107       382   34.1660  


BOTTLE FILE SALINITY & OXYGEN DQE 2ND QUALITY WORD CHANGES

The A14 water sample data file A14hy.txt with CTD and bottle salinity and 
oxygen values was screened and a second DQE quality word (Q2) added to the new 
bottle file A14N.HYD to indicate changes to the (Q1) Quality word. The 
following criteria was used to test the validity of the water sample salinity 
and oxygen values: for pressures less than 1000 decibars "bad" data with an 
absolute |Ds|<0.004 psu or |Dox| < 4.3 Um/kg are flagged as "good" in Q2. A 
test for "good" Q1 |Ds|>.1 psu at pressure less than 1000 decibars does not 
flag any "questionable" salinity data in Q2 since no |Ds| exceeds 0.008 psu for 
any depth as seen earlier in the upper panel of figure 5. For pressures greater 
than 1000 decibars, "good" bottle salinities with a |Ds|>0.007 psu (~3.8 
standard deviations) or oxygen differences |Dox|>4.3 Um/kg are flagged as 
"questionable" along with the CTD salinity in Q2. Scans in the water sample 
data file where the second quality word Q2 does not match the PI Q1 follows 
below and also in file A14N.chg:

                                                                            A14 CTD DQE

SALINITY Q2 CHANGES: 

The information below is duplicated in an ASCII file A14.CHG.


Changed WS Salts flags ds< 0.004& pw<1000 or ds> 0.007 for pw >1000 decibars 
STN  CAST  SAMP  BTL CTDPRS   CTDTMP  CTDSAL  CTDOXY   THETA   SALNTY  OXYGEN  Q1     Q2 
                 **                   ******* ******           ******* ******   *
 13   1     18   15  2995.9   2.6640  34.9140  239.6   2.4210  34.9070  240.9  22222 22232
 19   1      1   32     2.7  27.9520  35.6220  200.2  27.9510  35.6260  203.0  22232 22222


OXYGEN Q2 CHANGES:

Changed WS oxygen flags dox< 4.2 & pw< 1000 or  dox   > 4.2 for pw >1000 dbars 
STN  CAST  SAMP  BTL CTDPRS   CTDTMP  CTDSAL  CTDOXY   THETA   SALNTY  OXYGEN  Q1     Q2 
                 **                   ******* ******           ******* ******   *
 13   1     18   15  2995.9   2.6640  34.9140  239.6   2.4210  34.9070  240.9  22222 22232
 19   1      1   32     2.7  27.9520  35.6220  200.2  27.9510  35.6260  203.0  22232 22222


OXYGEN Q2 CHANGES:

Changed WS oxygen flags dox< 4.2 & pw< 1000 or  dox   > 4.2 for pw >1000 dbars 
STN  CAST  SAMP  BTL CTDPRS   CTDTMP  CTDSAL  CTDOXY   THETA   SALNTY  OXYGEN  Q1     Q2 
                 **                   ******* ******           ******* ******   *
  4   1      3   19    46.4  17.3730  35.7990  132.1  17.3650  35.8000  129.2  22223 22222
 12   1     13   20  1845.4   3.7080  34.9730  248.4   3.5590  -9.0000  254.2  22292 22293
 13   1      2   31    28.1  26.6500  35.5900  205.8  26.6440  35.5840  204.0  22233 22232
 13   1      8   25   995.3   4.4940  34.6530  156.7   4.4150  34.6520  160.1  22223 22222
 13   1     15   18  2586.6   2.9000  34.9300  243.7   2.6930  -9.0000  251.2  22292 22293
 13   1     27    6  4797.0   2.1790  34.8660  244.1   1.7460  -9.0000  250.9  22292 22293
 13   1     28    5  4997.3   2.1490  34.8610  245.0   1.6920  -9.0000  251.4  22292 22293
 14   1     27    6  4601.7   2.2010  34.8710  244.8   1.7910  -9.0000  250.6  22292 22293
 14   1     29    4  4898.3   2.1620  34.8630  245.8   1.7170  -9.0000  252.0  22292 22293
 15   1     27    6  4796.9   2.1780  34.8660  245.1   1.7450  -9.0000  250.8  22292 22293
 17   1     19   14  2796.0   2.7670  34.9200  242.0   2.5420  -9.0000  249.8  22292 22293
 22   1      1   32     3.7  26.8860  35.8000  272.3  26.8850  35.8010  202.8  22223 22322
 22   1      2   31    46.6  19.4150  35.7530  177.6  19.4070  35.7790  155.5  22233 22332
 27   1      1   32     4.1  27.0690  35.7890  200.4  27.0680  35.7910  201.8  22223 22222
 28   1      3   30    96.2  15.1810  35.5460  100.9  15.1660  35.5300   96.8  22233 22232
 32   1     15   18  1396.9   4.0780  34.8460  203.3   3.9670  34.8430  199.0  22222 22223
 32   1     18   15  1996.4   3.4240  34.9380  238.0   3.2650  -9.0000  243.3  22292 22293
 37   1      1   32     3.5  25.5600  36.3450  202.2  25.5590  36.3430  204.5  22223 22222
 37   1     13   20   795.1   4.7580  34.4830  136.3   4.6940  34.4840  140.5  22223 22222
 46   1     25    3  2854.7   2.5480  34.8930  242.2   2.3220  -9.0000  250.0  22292 22293
 51   1     30    3  3049.3   2.4580  34.8870  239.1   2.2140  34.8880  243.7  22222 22223
 54   1     11   22  1195.8   3.7000  34.6550  185.9   3.6100  34.6600  181.7  22222 22223
 67   1     21   12  2595.8   2.4700  34.8630  235.5   2.2710  -9.0000  241.6  22292 22293
 73   1      1   32     3.8  24.8670  36.1190  285.2  24.8660  36.1190  212.5  22223 22322
 73   1      2   31    36.8  23.1310  36.0820  297.6  23.1230  36.0510  221.0  22233 22332
 90   1     14   19  1195.2   2.9080  34.4210  204.8   2.8260  34.4230  200.4  22222 22223
 92   1     30    3  3319.7   2.1540  34.8400  229.6   1.8900  34.8370  233.8  22222 22223
 94   1     21   12  1795.2   2.7010  34.7000  195.8   2.5720  34.6970  190.5  22222 22223
 94   1     23   10  2196.2   2.5990  34.7830  210.5   2.4350  34.7820  206.1  22222 22223
 97   1     14   19  1196.8   2.7810  34.3770  198.6   2.7000  34.3790  203.4  22222 22223
101   1      1   32    10.0  11.0120  34.4190  301.3  11.0110  34.4210  278.8  22223 22322
102   1     23   10  3196.0   1.6490  34.7800  219.9   1.4090  34.7780  215.5  22222 22223
106   1     20   13  1997.2   2.4480  34.7660  194.6   2.3050  34.7660  198.8  22222 22223



__________________________________________________________________________________________
__________________________________________________________________________________________



A13 DATA QUALITY EVALUATION: NUTRIENTS AND DISSOLVED OXYGEN 
(Joe C. Jennings, Jr and Louis I. Gordon)
1999 AUG 11


OVERALL IMPRESSIONS:

The A13 section is largely meridional, running northward from 40S to 
terminate off the coast of Africa.  Except for the last few stations, the 
entire section lies to the east of the Greenwich Meridian, crossing the 
eastern Cape and Angola basins and ending in the Gulf of Guinea. The A13.HYD 
data file includes data from 134 stations, numbered 109-243.  Dissolved 
oxygen, nitrate, phosphate, and silicate were determined, but nitrite is not 
separately reported. The column labeled "NITRAT" in the ".HYD" file should be 
relabeled to reflect the fact that it is really "N+N".  In most of the water 
column the difference between "N+N" and nitrate is negligibly small, so the 
lack of nitrite data doesn't seriously compromise the utility of this data 
set.

A13 had a few more obvious bottle problems and more noisy deep-water data than 
was present in the A14 or A15 sections.  Most of the data should be fine, but 
there is more scatter in multi-station deep water "envelopes" than in the 
other south Atlantic WOCE sections we have been examining.


COMPARISONS WITH OTHER WOCE CRUISES:

A13 crosses the A08 and A10 zonal sections.  We made very preliminary 
comparisons of the data at the intersections of A13 with A10 and A08.  (We 
have been funded separately to do a detailed examination of WOCE line 
crossings that is presently underway.)

A13/A10:  
A13 crosses the A10 section at ca. 10E, 30S in the eastern Cape basin.  This 
is a highly dynamic region because of the Agulhas Current and it's retroflection 
zone, so we have confined our comparisons to the deep water (3000 - 5000 m) 
where the T/S properties of the two cruises were indistinguishable. We compared 
vertical profiles and property/theta plots from the three stations in each sec-
tion closest to the intersection point. 

There is good agreement between the dissolved oxygen and silicate data from 
the two cruises, but the nitrate and phosphate data from A13 are lower than on 
A10.  At temperatures below 2C, the A13 stations are ca. 1.5 M/kg lower in 
nitrate and 0.08 M/kg lower in phosphate than the A10 stations.  There is 
also more noise (or variability) in the A13 data.

A13/A08:  
These two sections cross in the Guinea Basin at ca. 5E, 11.5S.  A13 has much 
higher dissolved oxygen than A08 and higher silicate and nitrate as well. The 
offsets of ca. 15 - 18 M/kg in oxygen, 2.0 - 2.5 M/kg in silicate, and 0.4 - 
0.6 M/kg in nitrate are similar to the offsets noted between A08 and the A14 
and A15 sections, so are probably the result of calibration problems in the A08 
data. (No phosphate data was reported for A08).

                                                                            A13 NUTs/O2 DQE

COMMENTS ON SPECIFIC STATIONS:

In a few cases, there are nutrient concentrations reported as zero, when we 
think the intention was simply not to report those data.  These 0.0's should 
have been -9's to indicate that the data were not reported and the quality 
bytes should have been "9".  This comment applies to one or more samples at 
stations 109, 155, 171, 192, and 237. We have flagged these as questionable in 
the Q2 quality word.

At station 179, the deep silicates from bottles 24 - 32 trend increasingly 
higher compared to adjacent stations. This may be an instrumental drift 
problem, which in some cases is correctable.



Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  109      5       196.6   High   High                 
  109     25      2097            0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     26      2099.7          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     27      2098.4          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     28      2099.4          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     29      2097.8          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     30      2101.9          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     31      2097.6          0/-9                 No silicate? Value is 0.00 vs. -9.00
  109     32      2096.6          0/-9                 No silicate? Value is 0.00 vs. -9.00
  110      7       147.5   Low                         
  110      8       176.6   Low                         
  110      9       177.4   Low                         
  111      6       126.6   High                        
  111      9       247.1   Low                         
  111     10       296.3   Low                         
  111     11       296.6   Low                         
  111     12       325.6   Low                         
  112      3        46.4          Low                  
  113      2        46.4   Low                         
  116      8       694.8                        Low    
  116     20      2795                          Low    
  117      2        46.4   Low                         Does not agree with CTD Oxy.
  117      3       120.6   High                        Does not agree with CTD Oxy.
  117      4       195.9   Low    Low    Low    Low    Does not agree with CTD Oxy.
  117      6       395.5   Low                         Does not agree with CTD Oxy.
  117      7       595.9   Low                         Does not agree with CTD Oxy.
  117      8       774.2   Low    High                 Does not agree with CTD Oxy.
  117      9       994.4   Low                         Does not agree with CTD Oxy.
  117     10      1195.1                        High   
  117     12      1596.5   High                        Does not agree with CTD Oxy.
  117     14      1796.1   High                        Does not agree with CTD Oxy.
  117     15      1996.7   High                        Does not agree with CTD Oxy.
  118      9       816.5          High                 
  118     16      1995                          Low    No kink in N+N or O2.
  118     12      1393.9                        Low    Poor duplicate.
  118     13      1393.8                        Low    Poor duplicate.
  119      5       296            High                 
  119      6       396.3   High                        
  119      8       794.2          High   High   High   Silicate most obviously high.
  121     11       995.7                        High   
  121     26      3998.6                        High   

                                                                            A13 NUTs/O2 DQE

Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  123     23      3394.8                 Low           No kink in PO4 or O2.
  123     31      4996.4                 Low           No kink in PO4 or O2.
  124      1         3.4   Low                         Does not agree with CTD Oxy.
  124      2         3.1   Low                         Does not agree with CTD Oxy.
  124      5       196.7   Low                         Does not agree with CTD Oxy.
  124      6       394.6   Low                         Does not agree with CTD Oxy.
  124     22      3195.7   High                        No Nuts reported
  125      6       594.3   High                        Does not agree with CTD Oxy.
  126      3       120.9                        High   
  126     10       993.8          Low                  
  127     23      3395.4          Low                  No kink in PO4 or O2.
  129      7       344.7          Low           High   
  130      5       196.2   High                        Does not agree with CTD Oxy.
  130     11       994.5   Low                         vs.Theta
  130     12      1195.6   High                        vs.Theta
  130     31      4795.3                 Low           No kink in PO4 or O2.
  131     14      2194.4                 Low           No kink in PO4 or O2.
  133      3        46.5   Low                         Does not agree with CTD Oxy.
  135     20      2994.7                 Low           
  135     23      3593.2                 Low           No kink in PO4 or O2.
  135     28      4598.6                        Low    No kink in N+N or O2.
  136      9       891.2   High                        Does not agree with CTD Oxy.
  136     10       996.5          High   High   High   
  137     28      4601.7   High                        No kink in N+N or PO4.
  138     19      2998.2                 High          No kink in PO4 or O2.
  138     20      3194.2                 Low           No kink in PO4 or O2.
  138     28      4599.4                 Low           
  138     31      5074.8                 Low           No kink in PO4 or O2.
  138     32      5149.9                 Low           No kink in PO4 or O2.
  139      9       995.3   Low                         vs.Theta
  139     23      3596.3                 Low           No kink in PO4 or O2.
  140      8       795.5   High                        vs.Theta
  142     19      2795.2                        Low    Poor duplicate.
  142     28      4397.5                 Low    Low    Si and O2 look Ok.
  142     30      4795.9                 Low    Low    Si and O2 look Ok.

                                                                            A13 NUTs/O2 DQE

Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  146      5       495.2   High                         
  146      7       705     Low           High          
  146     12      1194.6                 Low           Poor duplicate.
  146     23      3396                          Low    
  146     27      4196.8                 Low    Low    Si and O2 not reported.
  146     28      4398.2                 Low    Low    Si and O2 not reported.
  146     30      4798                   Low    Low    Si looks Ok.
  146     31      4798.1                 Low           
  147      7       657.3   Low           High          
  147     10      1194.6                 High          Poor duplicate.
  148      9       986.9                 Low           Poor duplicate.
  148     10       990.9                 Low           Poor duplicate.
  148     25      3796                          Low    
  148     26      3996.2                        Low    N+N and Si look Ok.
  150     19      2795.6                        Low    
  150     28      4397.6                        Low    
  151     25      3796.8                 High          Poor duplicate.
  152     14      1793.8                 Low           No kink in PO4 or Si.
  152     15      1994.7                 Low           No kink in PO4 or Si.
  152     18      2593.8                 Low           No kink in PO4 or Si.
  152     20      2998.7   High                         
  152     21      3195.4                 Low           
  152     26      3996.1                 Low           
  152     28      4396.9                 Low           No kink in PO4 or Si.
  152     29      4597.1                 Low           No kink in PO4 or Si.
  153      3        81.3   Low                          
  154     19      2793.8                        Low    
  154     22      3394.1                 Low           Poor duplicate.
  154     23      3393.9                 High          Poor duplicate.
  154     29      4600                          High   
  154     30      4797.2                 Low           PO4 higher than Station 153
  155      7       395.4   Low    0/-9   0/-9   0/-9   No Nuts reported. 0.0's instead of -9's
  155     32      4961.1   Low           Low           
  156      3        97.4   Low                         Does not agree with CTD Oxy.
  156     25      3597.7                        Low    No change in N+N.
  156     26      3796.3                        Low    No change in N+N.
  157      5       398.8   Low                          

                                                                            A13 NUTs/O2 DQE

Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  158      6       426.8   Low                          
  158     18      2398.2                 Low           
  158     24      3396.9                 Low           
  158     26      3796.5                 Low           No change in PO4.
  158     27      3997.6                 Low           No change in PO4.
  158     28      4192.9                 Low           No change in PO4.
  158     29      4397                   Low           
  158     30      4599.9                 Low           No change in PO4.
  158     31      4806.3                 Low           No change in PO4.
  158     32      4811                   Low           No change in PO4.
  159      5       346.4   Low                          
  161     17      2197.7                 Low           
  161     19      2596.7                 Low    Low    
  161     23      3395.6          High          Low    
  161     24      3594.2          High                 
  161     25      3801.1          High                 
  161     28      4402.5                 Low    Low    
  161     32      4811.6                 Low    Low    
  163      7       556.1          Low    Low    Low    Oxygen looks ok.
  164     26      3596.5                 Low    Low    
  164     31      4597.6                 Low           
  165     19      2596.2                        Low    
  166      4       194.9   Low                          
  168     26      3798.6                 Low           
  171     19      2713.4                 Low           
  171     20      2713.2          0/-9   0/-9          Values 0.0 instead of -9.0?
  172      7       486.7   High          Low            
  172     16      1994.9                 Low           
  172     18      2396.2                 High          
  172     20      2561.6                 Low           
  173      6       396.5                        Low    Poor duplicate.
  173     18      2395.1                 Low           
  173     23      3396                   Low           
  173     24      3425.9                 Low           
  177     16      1996.3                 Low           
  177     23      3395.8                 Low           
  177     25      3795.5                 Low           
  177     28      4147.1                 Low           
  177     29      4145.6                 Low           
  178      4       164.6   Low    High   High   High   
  178      5       198.1          High   High   High   
  179     24      3997.4          High                 These silicates get increasingly high,
  179     25      4197.6          High                 maybe an instrumental problem?
  179     26      4397.4          High                 
  179     27      4597.2          High                 
  179     28      4800.2          High                 
  179     29      4997.2          High                 
  179     30      5196.1          High                 
  179     31      5301.7          High                 
  179     32      5343.9          High                 

                                                                            A13 NUTs/O2 DQE

Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  181     14      1794.1                        Low    
  181     26      4197.5                        Low    
  181     31      5195.6                 Low           
  183      4       195.9   High                         
  184     28      4796.8                 Low           
  185     14      2195.6                        Low    
  185     15      2396.5                        Low    
  185     16      2593.7                        Low    
  186     24      3995.7                        High   
  187     25      4396.6          High                 
  187     26      4596.4          High                 
  189     14      2196.9                        Low    
  189     23      3995                          Low    
  192     13      1995.4          0/-9                 0.0 vs. -9.0?
  192     28      4997.1                 Low    Low    Si and O2 look Ok.
  192     30      5400.9                 Low    Low    Si and O2 look Ok.
  193     14      1994.1                        Low    
  193     28      4798     High                         
  194      9       245.2   High                         
  196      2        47     Low                         Does not agree with CTD Oxy.
  196     27      4796     High                         
  197      2        46     Low                          Does not agree with CTD Oxy.
  197     14      2195.3                        Low    
  197     28      4995.8                        Low    
  197     31      5549.4                        Low    
  198      2        45.7   Low                         Does not agree with CTD Oxy.
  198      6       594.5   High   High          Low    
  198      7       794.2   High   High          Low    
  198      8       996.2   High                         
  198     28      4997.3                 Low    Low    
  199      2        45.2   Low                         Does not agree with CTD Oxy.
  200      2        47     High                        Does not agree with CTD Oxy.
  200     25      4198.3                        Low    
  200     26      4395.7                        Low    
  200     28      4796.9                        Low    
  200     31      5399.6                        Low    
  200     32      5482.8                        Low    
  201      2        46     Low                         Does not agree with CTD Oxy.
  201     28      4797.6                 Low    Low    
  201     29      4997.8                        Low    
  201     30      5198.8                 Low    Low    
  202      2        46.6   Low                         Does not agree with CTD Oxy.
  203      2        46.7   Low                         Does not agree with CTD Oxy.
  203     14      2195.7                        Low    
  203     25      4396.1   High                        
  203     31      5346.7                 Low           
  204      2        46.2   Low                         Does not agree with CTD Oxy.
  205      2        46.6   Low                         Does not agree with CTD Oxy.
  205     28      4596.4                 Low           
  205     30      4998.8                 Low           
  206     24      3996.4                        High   
  206     31      5098.3                 Low          
  207     19      2795.1                        Low    
  207     21      3196.6                        High   
  207     25      3997.3                        High   
  207     29      4596.1          Low                  
  208      2        46     Low                         Does not agree with CTD Oxy.
  208     25      3995.8                        High   
  208     28      4396.8                 Low    Low    
  208     30      4796.8                 Low    Low    
  209      1        43.5   Low                         Does not agree with CTD Oxy.
  209      2        46.4   Low                         Does not agree with CTD Oxy.
  210      2        46     Low                         Does not agree with CTD Oxy.
  211     17      2995.3                 High          All at one depth.
  211     23      2996.4                 High          
  211     27      2996.9                 High          
  211     29      2996.1                 High          
  211     32      2996.6                 Low           
  212      2        46.4   Low                         Does not agree with CTD Oxy.
  212     12      1595.7                 High          
  212     17      2396.1                 Low           
  212     23      3596.4                 Low    Low    
  212     32      5025.5                 High          

                                                                            A13 NUTs/O2 DQE

Station sample  Pressure   O2     Si     NO3    PO4    Comments
------- ------  --------   ----   ----   ----   ----   ------------------------------------
  213      2        47.5   Low                         Does not agree with CTD Oxy.
  213     14      1795                   High          
  213     19      2795                   High          
  213     20      2995.6                 High          
  213     21      3196.2                 High          
  213     23      3596.1                 Low           
  213     31      4948.3                        Low    
  214      2        45.9   Low                         Does not agree with CTD Oxy.
  215     27      3996.8   Low                           
  217     16      1995.2   High                        vs.Theta
  217     19      2595.6   High                          
  222     24      3596.8                 Low            
  222     26      3996.5                 Low            
  222     28      4296.5                 Low            
  222     30      4356.4                 Low            
  229     22      3595.8   High                          
  230      2        46.3   Low                           
  231      2        46     Low                           
  232      2        45.6   Low                           
  233      2        45.6   Low                           
  234      2        46.1   Low                           
  234     13      1794.9          Low                   
  234     21      3197.1                        Low    
  234     23      3596                          Low    
  234     28      4596.5                        Low    
  235     18      2595.3                 Low           Poor duplicate.
  235     21      3197.1                 Low           
  235     24      3796.3                 Low           
  235     30      4879                   Low    Low    
  236      2        46.3   Low                           Does not agree with CTD Oxy.
  236     23      3597.2                        High   
  236     29      4746.7   High                        vs.Theta
  236     30      4810.5   High                        Does not agree with CTD Oxy.
  237      2        46.1   Low                         Does not agree with CTD Oxy.
  237     18      2795.7          0/-9                 0.0 vs. -9.0?
  238      2        46.4   Low                         Does not agree with CTD Oxy.
  238     21      2994                          Low    
  238     30      4696.2                 Low           
  239      1         3.8   High                        Does not agree with CTD Oxy.
  240      5       265.7                 Low           
  240     14      1995.5                 Low           
  240     15      3595.8                 High          
  241      2        44.5   High                        Does not agree with CTD Oxy.
  242      2        46.5   Low                         Does not agree with CTD Oxy.
  243      3        46.8   Low                         Does not agree with CTD Oxy.



__________________________________________________________________________________________
__________________________________________________________________________________________



A14 DATA QUALITY EVALUATION: NUTRIENTS AND DISSOLVED OXYGEN 
(Joe C. Jennings, Jr and Louis I. Gordon)
1999 AUG 11


OVERALL IMPRESSIONS:

The A14 section is a meridional section along ca. 9W, running from the coast 
of Africa south to 45S.  The section is to the east of the Mid-Atlantic Rise, 
crossing the Guinea and Angola basins and ending in the Cape basin.  It 
consists of stations 1 - 107.  Dissolved oxygen, nitrate, phosphate, and 
silicate were determined, but nitrite is not separately reported.  The column 
labeled "NITRAT" in the ".HYD" file should be relabeled to reflect the fact 
that it is really "N+N".  In most of the water column the difference between 
"N+N" and nitrate is negligibly small, so the lack of nitrite data doesn't 
seriously compromise the utility of this data set.
 
Overall, the data quality appears to be very high and the initial QC checking 
by the data originators caught the vast majority of the questionable data.  A 
considerable number of the dissolved oxygen values were flagged by the data 
originators, apparently on the basis of poor agreement with the CTD oxygen 
rather than problems obvious on vertical profiles or oxygen/theta plots.  We 
agreed with flagging some of these as questionable, but think the data 
originators may have been over zealous in some of their flagging.  Most of the 
oxygen samples flagged as questionable were from the upper water column where 
there are strong gradients and the poor fit with the CTD oxygen sensor may be 
due to the lag time of the sensor response more than to the bottle oxygen 
sampler.  The depth range or effective sampling position of the rosette 
bottles relative to the CTD oxygen sensor might also be a factor.


COMPARISONS WITH OTHER WOCE CRUISES:

A14 crosses the A08 and A10 zonal sections.  We made very preliminary 
comparisons of the data at the intersections of A15 with A10 and A08.  (We 
have been funded separately to do a detailed examination of WOCE line 
crossings that is presently underway.)

A14/A08: 
There are consistent and substantial offsets between the A14 and A08 station 
data where the two sections cross at ca 9W and 11.5S. The A14 silicate, 
nitrate, and dissolved oxygen are all higher than the A08 throughout most of the 
water column. (Phosphate was not reported in the A08 data.)  Below 2000m, where 
the vertical gradients of oxygen and nitrate are small, the offset is ca. 1.5 
m/kg in nitrate and 15 - 19 M/Kg in oxygen. The silicate difference is ca. 2 
M/Kg in the deep and bottom waters. A similar difference was observed between 
the A08 and the A15 sections.

A14/A10: 
The A14 and A10 nutrient and oxygen data largely overlap. Below 2500 m, the A14 
nitrate and phosphate data is slightly lower than the A10 data.  The A14 nitrate 
is ca 0.5 - 0.7 M/Kg lower than the A10 nitrate, while the phosphate is ca 0.04 
- 0.08 M/Kg lower. There are no clear differences in the deep silicates or 
oxygen. A14 stations 75 and 77 have slightly (0.6 M/Kg) higher silicates than 
the A10 stations, but A14 stations 76 and 78 agree well with the A10 data. A 
complete listing of flagged data is appended below:

                                                                            A14 NUTs/O2 DQE

Station sample  Pressure  O2     Si     NO3    PO4    Comments
------- ------  --------  ----   ----   ----   ----   ------------------------------------------
1       2       21.8      Low                         Does not agree with CTD oxygen sensor
2       2       21.3      Low                         Does not agree with CTD oxygen sensor
3       1       0.9       High                        Does not agree with CTD oxygen sensor
3       2       22        Low                         Does not agree with CTD oxygen sensor
4       1       1.1       High                        Does not agree with CTD oxygen sensor
4       2       21.8      Low                         Does not agree with CTD oxygen sensor
5       1       21.7      Low                         Does not agree with CTD oxygen sensor
5       3       71.2      High                        Does not agree with CTD oxygen sensor
5       4       95.6      High                        Does not agree with CTD oxygen sensor
5       11      595.8     High                        Does not agree with CTD oxygen sensor
6       1       1.8       High                        Does not agree with CTD oxygen sensor
7       2       46.9      Low                         Does not agree with CTD oxygen sensor
7       16      1845.9    Low                         
7       17      1995.6    Low                         
8       3       31.7      Low                         Does not agree with CTD oxygen sensor
9       2       46        Low                         Does not agree with CTD oxygen sensor
10      6       396.6     Low                         Does not agree with CTD oxygen sensor
11      17      2846.7           High                 
11      26      4395.6           High                 
12      3       96.8      Low                         
13      15      2586.6    High                        
13      27      4797      High                        
13      28      4997.3    High                        
14      27      4601.7    High                        
14      29      4898.3    High                        
15      27      4796.9    High                        
17      2       46.9      High                        Does not agree with CTD oxygen sensor
17      19      2796      High                        


                                                                            A14 NUTs/O2 DQE

Station sample  Pressure  O2     Si     NO3    PO4    Comments
------- ------  --------  ----   ----   ----   ----   ------------------------------------------
21      2       44        Low                         Does not agree with CTD oxygen sensor
21      3       66.9      Low                         Does not agree with CTD oxygen sensor
21      6       595.4     High                        Does not agree with CTD oxygen sensor
22      1       3.7       Low                         Does not agree with CTD oxygen sensor
22      2       46.6      Low                         Does not agree with CTD oxygen sensor
23      2       30.3      Low                         Does not agree with CTD oxygen sensor
24      2       47.4      Low                         Does not agree with CTD oxygen sensor
25      9       495.4     High                        
25      10      596       High                        
26      9       495.8     High                 Low    
27      3       95.8      Low                         Does not agree with CTD oxygen sensor
28      7       295.6     Low                         Does not agree with CTD oxygen sensor
29      3       95.1      Low                         Does not agree with CTD oxygen sensor
30      1       3.6       Low                         Does not agree with CTD oxygen sensor
32      3       47        High                        Does not agree with CTD oxygen sensor
32      4       72.5      Low                         Does not agree with CTD oxygen sensor
32      5       115.9     Low                         Does not agree with CTD oxygen sensor
32      12      795.7     High                        Does not agree with CTD oxygen sensor
33      3       70.8      Low                         Does not agree with CTD oxygen sensor
33      4       96.5      Low                         Does not agree with CTD oxygen sensor
34      3       97.8      Low                         Does not agree with CTD oxygen sensor
34      4       145.1     Low                         Does not agree with CTD oxygen sensor
35      8       596.7     High                        
35      9       596.7                   Low           
36      3       96.9      Low                         Does not agree with CTD oxygen sensor
36      12      895.1     High                        
38      3       128.1     Low                         Does not agree with CTD oxygen sensor
39      3       146.2     Low                         All nutrients look the same as next Btl. down.

                                                                            A14 NUTs/O2 DQE

Station sample  Pressure  O2     Si     NO3    PO4    Comments
------- ------  --------  ----   ----   ----   ----   ------------------------------------------
40      3       95.3      High                        
41      3       97        Low                         Does not agree with CTD oxygen sensor
41      4       171.7     Low                         Does not agree with CTD oxygen sensor
41      12      794.5     Low                         
42      3       95.2      Low                         Does not agree with CTD oxygen sensor
43      3       96.7      High                        Does not agree with CTD oxygen sensor
43      15      1369.7    Low                         
44      3       97.6      High                        Does not agree with CTD oxygen sensor
44      8       396.3     High                        Does not agree with CTD oxygen sensor
44      10      596.3     High                        Does not agree with CTD oxygen sensor
46      3       68.1      High                        Does not agree with CTD oxygen sensor
46      25      2854.7    High                        vs Theta
48      2       27.2      High                        Does not agree with CTD oxygen sensor
49      5       71        Low                         Does not agree with CTD oxygen sensor
49      6       96.8      Low                         Does not agree with CTD oxygen sensor
49      7       146.8     Low                         Does not agree with CTD oxygen sensor
50      2       47.1      High                        Does not agree with CTD oxygen sensor
51      2       47.4      Low                         vs Theta
60      1       3.4       High                        
60      25      3595.7           Low                  
62      11      694.5     High                        
65      3       96.3      High                        vs Theta
67      21      2595.8    High                        No feature in nutrients.
72      5       196.1     Low    High   High   High   
72      8       496.8     Low                         
73      1       3.8       Low                         Does not agree with CTD oxygen sensor
73      2       36.8      Low                         Does not agree with CTD oxygen sensor
75      19      1995.8    High                        
76      1       4.1       High                        Does not agree with CTD oxygen sensor
76      2       3.9       High                        Does not agree with CTD oxygen sensor
77      10      697.6     High                        No feature in nutrients.
78      13      1194.4           High   Low    Low    

                                                                            A14 NUTs/O2 DQE

Station sample  Pressure  O2     Si     NO3    PO4    Comments
------- ------  --------  ----   ----   ----   ----   ------------------------------------------
80      11      696.1     Low                         No feature in nutrients.
80      14      1195.3    Low                         Does not agree with CTD oxygen sensor
81      2       57.3      High                        Does not agree with CTD oxygen sensor
85      4       147.1     Low                         Does not agree with CTD oxygen sensor
86      2       46.7      Low                         Does not agree with CTD oxygen sensor
86      3       120.6     High                        Does not agree with CTD oxygen sensor
87      2       51.7      High                        Does not agree with CTD oxygen sensor
87      3       96.6      Low                         Does not agree with CTD oxygen sensor
88      5       96.8      Low                         Does not agree with CTD oxygen sensor
90      6       296.5     Low                         Does not agree with CTD oxygen sensor
92      4       395.6     High                        Does not agree with CTD oxygen sensor
94      11      695.4     High                        Does not agree with CTD oxygen sensor
96      5       195.2     Low                         vs Theta
96      6       296.1     Low                         vs Theta
96      7       295.3     Low                         vs Theta
106     10      695.4     Low                         Does not agree with CTD oxygen sensor



__________________________________________________________________________________________
__________________________________________________________________________________________



WHPO-SIO DATA PROCESSING NOTES

LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a14      04/01/97  Arhan         DOC          Submitted hard copy in French

a13/a14  05/18/98  Arhan         CTD/BTL/SUM  Submitted for DQE
                   CTDPRS CTDTMP CTDSAL CTDOXY  THETA SALNTY OXYGEN NITRAT 
                   PHSPHT  SILCAT  PH   ALKALI TCARBN CFC-12 CFC-11 TRITUM 
                   HELIUM DELHE3  NEON

a14      07/09/98  Diggs         CTD/BTL/SUM  Website Updated

a13      08/11/99  Jennings-Jr.  NUTs/OXY     DQE Report Submitted to WHPO-SIO 
                   I put the file A13-q2.HY2 in your INCOMING directory. 
                   There should also be a WORD97 .DOC file with a summary of 
                   the nutrient and dissolved oxygen DQE comments.

a13/a14  11/15/99  Buck          DOC          Website Update; pdf version online

a13/a14  05/12/00  Arhan         CTD/BTL      Data NonPublic; Future ReleaseDate
                   This message is about the inclusion of the A13 and A14 
                   data (CTD and BTL) in the WOCE Version 2.0 CD-ROM, for which 
                   you recently contacted H. Mercier (A14) and myself (A13).
                           
                   Our intention was to release these data in a few months 
                   (next September). We therefore agree to have them included 
                   in the CD- ROM, as this will probably not be distributed 
                   before the end of the summer. Can we ask you, however, to 
                   keep the status of the data as non public on the WHPO server 
                   in the mean time? We thank you for sending us confirmation 
                   that this is possible.
                           
                   Our keeping these data non public until next september 
                   has not been related to the progression of the WHPO work 
                   that you mention in your last message: It has been rather 
                   dictated by the slower- than-planned progression of our own 
                   scientific analyses!

a13      07/05/00  Huynh         DOC          Website Updated txt version online

a13/a14  07/10/00  Huynh         DOC          Online pdf, txt versions updated
                   Both pdf and text docs have been updated and are online. (doc 
                   is in french, additional report is in english)


LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a13      08/23/00  Uribe         NUTs/OXY     Jennings' DQE Data put in new dir.
                   Moved A13-q2._hy2 from /usr/export/ftp-
                   incoming.2000.14.02/Data was received on August 11, 
                   1999.Time stamp in file is 19980630SA. Same date is on the 
                   online data. No relevant email was found. (see Jennings: 
                   8/11/98) Path is atlantic/a13/original/1998.06.30_HY2_SA.

a13/a14  11/16/00  Memery        CFCs         Data are Public
                   I would like that the CFC data of the A13 and A14 (as 
                   well as the A17, which, from what I have been told, are 
                   still not available!!) cruises were entirely open to any 
                   user interested.

a13/a14  11/21/00  Uribe         SUM          Submitted
                   Files were found in incoming directory under whp_reports. 
                   This directory was zipped, files were separated 
                   and placed under proper cruise. All of them are sumfiles.

a13/a14  01/10/01  Arhan         CTD/BTL      Data are Public
                   A few days ago, I received this message from B. Klein, 
                   who apparently could not read the A13+14 data on the WHPO CD 
                   rom, version 2. I have not checked myself, but this is 
                   surprising, as I wrote you last spring that they could be 
                   made available in version 2 (mail exchange of May 12th). 
                   Being public on the CD rom, they can naturally also be made 
                   available on the WHPO webb site.
                           
                   I would be grateful if you could check that these data 
                   are now public at the WHPO.

a14      01/14/01  Diggs         CTD/BTL      Website Updated, Data Public
                   All data have been decrypted and made public on our website.

a13/a14  01/15/01  Swift         CTD/BTL      Data are Public
                   Michel Arhan reminds me (in an email which I will 
                   forward separately) that we are overdue in making these data 
                   public on our web site. I presume we will make it so.

a13      01/16/01  Diggs         CTD/BTL      Website Updated; Data Public
                   All data have been decrypted and made public on our website.

a13/a14  06/27/01  Uribe         CTD          Exchange File Added to Website
                   CTD exchange files were put online.


LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a13/a14  07/30/01  Diggs         BTL          Exchange File Added to Website
                   Exchange file for bottle data produced and placed online.

a13      07/31/01  Diggs         CFCs         Update Needed; QUALT flag problems
                   Alex Kozyr alerted me to the problem with the flags for 
                   the Carbon params and I couldn't come to any clear 
                   resolution about their origins. He thinks that perhaps they 
                   came came from Parilla, but not for sure. In any case, we're 
                   remerging the CFCs with the original bottle file and re-
                   checking the flags carefully. Then, this file goes off to 
                   Alex to aid in the analysis of the TCARBN (and cousins). 
                   Once we get Alex's data back, we'll have a new file.

a14      08/24/01  Bartolacci    CO2/CFC      Update Needed; QUALT flag problems
                   CFC's must be remerged due to problem with QUALT flags, 
                   The following information was submitted by S. Diggs for A13 
                   and is already in the data base, but also covers A14

a14      11/29/01  Millard       CTD          DQE Nearly Complete
                   I hope it's possible to get an extension on my DQE 
                   contract.  The current funds didn't arrive until late June 
                   2001. I've finished or nearly finished checking over & 
                   writing up 3 of the 5 datasets we talked about QCing- (A13 
                   (submitted) , A14, & A23).  Cruise A17 is 2 legs with 235 
                   stations & will take more time.  Between X-mas holidays & a 
                   vacation in mid-Jan., I probably can not finish A17 until 
                   sometime in late Feb. 2002. Are there any more datasets to 
                   be QCed? I may have a little time available for DQEing one 
                   more cruise with money remaining.

a13      11/21/01  Millard       CTD          DQE Report Submitted WHPO-SIO
                   I used WORD 9.0 on a PC to create.

a14      12/10/01  Millard       CTD          DQE Report Submitted WHPO-SIO

a14      12/19/01  Diggs         CTD          Online Exchange files updated
                   CTD Exchange files re-made with new version (v1.0f) of 
                   make_exctd.pl. Corrects lat/lon problem. All files checked 
                   with JOA3.0, and placed on website.

a13/a14  12/19/01  Tibbetts      DOC          Online pdf, txt docs Updated 
                       New English pdf and text files online.


LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a13/a14  01/23/02  Kozyr         CO2          Online data are preliminary, 
                   The numbers for CO2 parameters you have in the A13/A14 
                   files are not from CDIAC. These are the raw data may be from 
                   CS. I received the final Co2 data from 3 differens PI just 
                   late last year right before my cruise. During the cruise I 
                   had chance to work on the co2 data and they are now in a 
                   good shape and waiting the hydrographic data with right 
                   quality flags. As soon as I get the correct hydro data I 
                   will merge the co2 data into the file and will send you the 
                   final file. If you look at the data files for both A13 and 
                   a14 sections on your web area you will see that even without 
                   CO2 parameters all flags do not correspond with the values.

a13/a14  01/23/02  Anderson      CFCs         Data Need to be merged
                   In the data history for a13 and a14 on Aug. 24, 2001 
                   Danie said that the CFC's needed to be remerged. This was 
                   obviously not done since the time stamp on the online files 
                   is my 1998 reformat. Are there new CFC's to be remerged or 
                   does my correcting the QUALT flags solve that problem? If 
                   they need to be remerged, where are the files? I can do that 
                   also.

a13/a14  01/23/02  Diggs         CFCs         Data Need to be merged 
                   Looks like the newer CFCs will come from Alex Kozyr. 
                   Once we get the corrected bottle file (NUTS) on the site, 
                   Alex will take care of the rest.

a13/a14  01/23/02  Bartolocci    CFCs         Data Need to be merged 
                   Hi Sarilee- That note from me in the data history for 
                   a13/a14 was just submitting a quote from Steve. At the time 
                   he thought that arrose from CFC data/flags sent by Parilla. 
                   It is unclear at this time if Parilla was ever querried on 
                   this and asked for new data. I think not. The ball was 
                   dropped on this one over the summer when Steve couldn't 
                   confirm this info with Alex, (Alex was moving offices and 
                   then out to sea until the end of the year). Also, your last 
                   date stamp precedes this inquiry, so if the problem 
                   originated from that work, this shouldn't matter.
                           
                   So, bottom line is that I don't think we ever got new 
                   data to be merged. I'm thinking you should proceed as you 
                   were, but obviously Steve should be asked... Steve? Does 
                   this sound about right? If it doesn't ring a bell, I'll come 
                   thru my emails one more time.
                           
                   And thanks, Sarilee for taking care of this. I'll let 
                   Alex know we're working on it and the file will be to him 
                   soon.


LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a13/a14  01/24/02  Anderson      BTL          Data Reformatted 
                   (ctdprs, ctdtmp, ctdsal, ctdoxy, theta, salnty, oxygen, 
                   silcat, nitrat, phspht, cfc-11, cfc-12, tritum, helium, 
                   delhe3, neon, tcarbn, alkali, ph) 

                   As noted by Alex Kozyr the QUALT1 flags were not correct. 
                   Went back to the original data file 
                   ...a13/original/FROM_FRANCE and reformatted putting the 
                   QUALT1 flags with their correct, I hope, parameters.

a13/a14  01/24/02  Anderson      BTL          Exchange File Created
                   Created exchange file for a14 bottle data. File is in 
                   ...atlantic/a14 and needs to be linked to the web page.

a13/a14  01/25/02  Bartolacci    BTL          Website Update; Exchange File Added
                   The newly created Exchange file for this cruise has been 
                   linked to the website. Index page has been edited to reflect 
                   the Q1 flag correction and A. Kozyr has been notified that 
                   these files are now available.

a13/a14  01/25/02  Diggs         CO2          Problems with qual flags corrected 
                   Alex, Sarilee has corrected the problems with the flags 
                   on the original bottle files for A13/A14. These data should 
                   be ready for and the CO2 parameters later today. I _think_ 
                   that we have everything sorted out here.

a13/a14  01/31/02  Kozyr         TCARBN       Final Data Submitted to WHPO-SIO
                   I have put 3 data files in WHPO ftp INCOMING area. These 
                   files are the final CO2-related data and quality flags for 
                   WOCE sections A14 (L'ATALANTE 35A3CITHER3/1), A13 
                   (L'ATALANTE  35A3CITHER3/2), and SR03/S04 (P12, 09AR9404_1).

a14      02/07/02  Muus          TCARBN/ALK   merged into BTL, new Exchange file
                   Merged TCO2, Alkalinity and pH into web file. New woce 
                      format and exchange files on-line.
                   Notes on A14   merging     Feb 7, 2002  D.Muus
                   1. Merged TCARBN, ALKALI and PH from: /usr/export/html- 
                      
public/data/onetime/atlantic/a13/original/2002.01.31._A13-  
                      a14_CO2_A-KOZYR/a14co2.txt into A14 bottle file from web 
                      (20020123WHPOSIOSA) [a14/original linked to a13/original]
                   2. Used QUALT1 codes for QUALT2.                   
                   3. Made new exchange file for Bottle data.
                   4. Checked new bottle file with Java Ocean Atlas.


LINE     DATE      CONTACT       DATA TYPE    DATA STATUS SUMMARY
-------  --------  ------------  -----------  ----------------------------------
a13      02/07/02  Muus          TCARBN/ALK   merged into BTL, new Exchange file
                   Merged TCO2, Alkalinity into web file. New woce format and 
                      exchange files on-line.
                   Notes on A13  merging   Feb 7, 2002 D.Muus
                   1. Merged TCARBN, ALKALI and PH from: /usr/export/html- 
                      public/data/onetime/atlantic/a13/original/2002.01.31._A13-  
                      a14_CO2_A-KOZYR/a13co2.txt into A13 bottle file from web 
                      (20020123WHPOSIOSA)
                   2. Used QUALT1 codes for QUALT2.                   
                   3. PH listed in both old bottle file and new co2 file 
                      but with all data values = -9.000 and quality code 9s. DOC 
                      file indicates pH taken by same group as alkalinity. 
                   4. Made new exchange file for Bottle data.
                   5. Checked new bottle file with Java Ocean Atlas.

a13      06/19/02  Klein         TR/NE/CFC    Updated Data & QUALT 2 Submitted
                   The whpo file was basically fine, but compared to our 
                   file 22 tritium values and 56 neon values were missing. I 
                   therefore included the tritium and neon values in the file I 
                   am sending you. The quality flags in byte 2 are updated for 
                   the tracers. CFC data are from the french, they were 
                   notified about changes in quality flags.

a14      06/19/02  Klein         TR/NE/CFC    Updated Data & QUALT 2 Submitted
                   The whpo file was basically fine, but compared to our 
                   file 22 tritium values and 112 neon values were missing. I 
                   therefore included the tritium and neon values in the file I 
                   am sending you. The quality flags in byte 2 are updated for 
                   the tracers. CFC data are from the french, they were 
                   notified about changes in quality flags.
                   
A13/A14  08/09/03  Kappa         DOC          Updated PDF & Text Cruise Reports
                   Updated figs for both CTD DQE reports to improve 
                      readability and to make them load much more quickly.
                   Updated WHPO-SIO Summary pages (paged 1-2)
                        combined a13 and a14 station tracks into one plot and
                         added it to page one.
                        clarified which Chief Scientists, legs, geographic 
                         boundaries, ports of call, numbers of stations, and
                         begin-end dates belong to which line: a13 or a14.
                        added contact info. for both Chief Scientists.
                        added links between WHPO-SIO table of contents and 
                         appropriate locations within body of report.
                   Added full-page map with both a13 and a14 station tracks.
                   Expanded links within PDF report and added color to make
                      them more visible.
                   Added links in PDF doc between PI-submitted table of 
                      contents and appropriate locations within body of report.
                   Added these WHPO-SIO Data Processing Notes
