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A.  CRUISE REPORT:  AR21
    (Updated Jun 2008)

A.1.  HIGHLIGHTS

                        WHP CRUISE SUMMARY INFORMATION

         WOCE section designation  AR21
Expedition designation (EXPOCODE)  3175MB91
                             Ship  R/V Malcolm Baldrige
  Chief Scientists & affiliations  LEG 1: Rik Wanninkhof/AOML
                                          Scott Doney/NCAR
                                   LEG 2: Donald K. Atwood/AOML
                                          Denis W. Frazel/AOML
                            Dates  Leg 1: 4 JUL 1993 to 24 JUL 1993 
                                   Leg 2: 2 AUG 1993 to 30 AUG 1993
                    Ports of call  Leg 1: Fortaleza, Brazil; Cape Verde; Madeira
                                   Leg 2: Madeira 
               Number of stations  83

                                               63°14'38" N 
            Geographic boundaries  29°2'8.5" W             18°8'59" W
                                               5°0'19.8" S

     Floats and drifters deployed  0 
   Moorings deployed or recovered  0 

                                  Contributing Authors
       G. Berberian  J.L. Bullister  R.D. Castle   S.C. Doney  R.A. Feely  
       D. Frazel     D. Greeley      B.E. Huss     E. Johns    M. Lamb
       K. Lee        F. Menzia       F.J. Millero  L.D. Moore  R. Wanninkhof
       D. Wisegarber

                     Chief Scientists' Contact Information:
    Rik Wanninkhof • NOAA/AOML • 4301 Rickenbacker Causeway * Miami, FL 33149
   tel: (305) 361-4379 • fax: (305) 361-4392 • Email: Rik.Wanninkhof@noaa.gov

     Scott Doney • Department of Marine Chemistry and Geochemistry • MS #25
         Woods Hole Oceanographic Institution • Woods Hole, MA 02543-1543
      Tel: (508) 289-3776 • Fax: (508) 457-2193Email: Email: sdoney@whoi.edu

          Donald K. Atwood • NESDIS Office of Research and Applications
 World Weather Bldg. Room 601-18 • 5200 Auth Road • Camp Springs, MD 20746-4304 
    Tel: 301-763-8102 Ext 206 • Fax 305-763-8580 • Email: Don.Atwood@noaa.gov

     Denis W. Frazel NOAA/AOML • 4301 Rickenbacker Causeway, Miami, FL 33149



NOAA Data Report ERL AOML-32
CHEMICAL AND HYDROGRAPHIC PROFILES AND UNDERWAY MEASUREMENTS FROM THE EASTERN 
NORTH ATLANTIC DURING JULY AND AUGUST OF 1993

Atlantic Oceanographic and Meteorological Laboratory Miami, Florida February 
1998

NOAA
UNITED STATES           NATIONAL OCEANIC AND          Environmental Research
DEPARTMENT OF COMMERCE  ATMOSPHERIC ADMINISTRATION    Laboratories

William M. Daley        D. JAMES BAKER                James L. Rasmussen
Secretary               Under Secretary for Oceans    Director
                        and Atmosphere/Administrator

                                   NOTICE

Mention of a commercial company or product does not constitute an endorsement 
by NOAA/ERL.  Use of information from this publication concerning proprietary 
products or the tests of such products for publicity or advertising purposes 
is not authorized.

                            LOCATION OF DATA FILES

Data files can be downloaded from AOML's web site 
(http:Hwww.aoml.noaa.gov/ocd/oaces/data) or by anonymous ftp (ftp.aoml.noaa.gov) 
from the directory pub/ocd/carbon/pc/natl93. For help in downloading, contact 
either:

    Betty Huss  305-361-4395  huss@aoml.noaa.gov
    Bob Castle  305-361-4418  castle@aoml.noaa.gov

or by regular mail to either of the above at:

    NOAA/AOML/OCD
    4301 Rickenbacker Causeway
    Miami, FL 33149



                              TABLE OF CONTENTS


PRINCIPAL INVESTIGATORS AND PROJECT PARTICIPANTS 
ABSTRACT
1.  INTRODUCTION 
    1.1.  Description of the Study Area
2.  DATA COLLECTION AND ANALYTICAL METHODS 
    2.1.  Hydrographic Methods 
        2.1.1.  CTD and Hydrographic Operations 
        2.1.2.  Nutrient Analysis 
            2.1.2A.  AOML Nutrients 
            2.1.2B.  University of Washington Nutrients 
        2.1.3.  CFC Analysis
    2.2.  Carbon Parameters
        2.2.1.  Total Dissolved Inorganic CO2(TCO2)
        2.2.2.  Discrete Fugacityof CO2(ƒCO2)
        2.2.3.  Total Alkalinity and pH 
    2.3.  Underway Measurement Methods 
        2.3.1. Underway ƒCO2 Measurements 
3.  ACKNOWLEDGMENTS 
4.  REFERENCES 
APPENDIX A: Contour Plots 



                                LIST OF FIGURES


 1.  North Atlantic 1993 Cruise Track 
 2.  North Atlantic 1993 CTD Bottle Trip Depths 
 3.  Oxygen vs. Pressure 
 4.  CTD Salinity vs. Pressure 
 5.  Potential Temperature vs. Pressure 
 6.  Sigma Theta vs. Pressure 
 7.  Sigma-2 vs. Pressure 
 8.  Sigma-4 vs. Pressure 
 9.  AOML N03 vs. Pressure 
10.  U.W. & AOML N03 vs. Pressure 
11.  AOML P04 vs. Pressure 
12.  U.W. & AOML P04 vs. Pressure 
13.  AOMLS SiO(4) vs. Pressure 
14.  U.W. & AOMLS SiO(4) vs. Pressure 
15.  CFC-11 vs. Pressure 
16.  CFC-12 vs. Pressure 
17.  Total CO2 vs. Pressure 
18.  ƒCO2 vs. Pressure 
19.  pH vs. Pressure 
20.  Total Alkalinity vs. Pressure 
21.  Underway ƒCO2 and Sea Surface Temperature (Leg 0) 
22.  Underway ƒCO2 and Sea Surface Temperature (Leg 1) 
23.  Underway ƒCO2 and Sea Surface Temperature (Leg 2) 
24.  Underway ƒCO2 and Sea Surface Temperature (Leg 3) 
25.  Thermometer vs. Thermistor Comparison (Underway fCO2 System)
26.  Comparison of U.W. & AOML N03 
27.  Comparison of U.W. & AOML PO4 
28.  Comparison of U.W. & AOMLS SiO(4) 



PRINCIPAL INVESTIGATORS AND PROJECT PARTICIPANTS

PROJECT PRINCIPAL INVESTIGATORS

PROJECT                FUNDED PI                            AFFILIATION
--------------         -----------------------------------  -----------
CTD, Sal, & O2         Dr. R. Wanninkhof                    AOML
Nutrients              Dr. D. Atwood & Dr. R. A. Feely      AOML/PMEL
CFCs                   Dr. J. L. Bullister                  PMEL
TCO2 & fCO2            Dr. R. Wanninkhof & Dr. R. A. Feely  AOML/PMEL
TAlk & pH              Dr. F. Millero                       RSMAS
13C                    Dr. P. Quay                          U.W.
Productivity           Dr. F. Chavez                        MBARI
Underway pH            Dr. A. Dickson                       SIO
Ozone & CO             Dr. T. P. Carsey                     AOML


CRUISE PARTICIPANTS

LEG 1
Chief Scientist:       Dr. Rik Wanninkhof                   AOML
Co-Chief Scientist:    Dr. Scott Doney                      NCAR

ANALYST                DATA TYPE                            AFFILIATION
-------------------    -----------------------------------  -----------
Jennifer Aicher        TAlk, pH                             RSMAS
Lloraine J. Bell       UW pH                                SIO
George Berberian       Nutrients                            AOML
Kurt Buck              Productivity                         MBARI
Robert Castle          Data Management                      AOML
Hua Chen               Discrete ƒCO2                        AOML, CIMAS
Dana Greeley           CFCs                                 PMEL
Kirk Hargreaves        CFCs                                 PMEL
Elizabeth House        13C                                  U.W.
Kathy Krogslund        Nutrients                            U.W.
Tom Lantry             TCO2                                 AOML
Kitack Lee             TAlk, pH                             RSMAS
Sanjay Mane            TAlk, pH                             RSMAS
Lloyd Moore            Nutrients                            AOML
Sonia Olivella         TAlk, pHR                            SMAS
Robert Roddy           CTD operations & O2                  AOML
Marta Sanderson        Productivity                         MBARI
Sue Service            Productivity                         MBARI
Michael Shoemaker      Electronics Technician               AOML
Margie Springer-Young  Atmospheric O2 & CO2                 AOML
Matt Steckley          Discrete & UW ƒCO2                   AOML
Gregg Thomas           CTD operations & Salinity            AOML
Kevin Wills            TCO2                                 PMEL
Dave Wisegarver        CFCs                                 PMEL


LEG 2
Chief Scientist:       Dr. Donald K. Atwood                 AOML
Co-Chief Scientist:    Dr. Denis W. Frazel                  AOML


ANALYST                DATA TYPE                            AFFILIATION
---------------------  -----------------------------------  -----------
Jennifer Aicher        TAlk, pH                             RSMAS
Lloraine J. Bell       UW pH                                SIO
George Berberian       Nutrients                            AOML
Dave Bitterman         CTD operations                       AOML
Kurt Buck              Productivity                         MBARI
Hua Chen               Discrete ƒCO2                        AOML, CIMAS
Cathy Cosca            Discrete ƒCO2                        PMEL
Dana Greeley           CFCs                                 PMEL
Kirk Hargreaves        CFCs                                 PMEL
James Hendee           Data management                      AOML
Tom Lantry             TCO2                                 AOML
Kitack Lee             TAlk, pH                             RSMAS
Sanjay Mane            TAlk, pH                             RSMAS
Fred Menzia            CFCs                                 PMEL
Lloyd Moore            Nutrients                            AOML
Victor Ross            CTD data reduction, survey           AOML
Brian Salem            13C                                  U.W.
Marta Sanderson        Productivity                         MBARI
Michael Shoemaker      Electronics Technician               AOML
Margie Springer-Young  Atmospheric O2 & CO                  AOML
Matt Steckley          Discrete & UW ƒCO2                   AOML
Gregg Thomas           CTD operations & Salinity            AOML
Jia-Zhong Zhang        TAlk, pHR                            SMAS



KEY TO AFFILIATION ABBREVIATIONS

AOML   Atlantic Oceanographic and Meteorological Laboratory
CIMAS  Cooperative Institute for Marine and Atmospheric Studies
MBARI  Monterey Bay Aquarium Research Institute
NCAR   National Center for Atmospheric Research
PMEL   Pacific Marine Environmental Laboratory
RSMAS  Rosenstiel School of Marine and Atmospheric Sciences
SIO    Scripps Institution of Oceanography
U.W.   University of Washington


KEY TO DATA TYPE ABBREVIATIONS

13C     13C/12C stable isotopic ratio of TCO2
CFCs    Chlorofluorocarbons
ƒCO2    Fugacity of Carbon Dioxide
O2      Dissolved Oxygen
Talk    Total Alkalinity
TCO2    Total Carbon Dioxide



ABSTRACT

From July 4 to August 30, 1993, the National Oceanic and Atmospheric 
Administration's (NOAA) Ocean-Atmosphere Carbon Exchange Study (OACES) and 
Radiatively Important Trace Species (RITS) programs participated in an 
oceanographic research cruise aboard the NOAA ship MALCOLM BALDRIGE.  The 
objectives of the OACES component were to determine the source and sink 
regions of CO2 in the Equatorial and North Atlantic during the summer and to 
establish a baseline of total carbon inventory in the region.  Data were 
collected from 5°S to Iceland along a nominal longitude of 20°W.  This report 
presents only the OACES-related data from legs 1, 2A, and 2B, including 
hydrography, nutrients, carbon species, dissolved oxygen, total inorganic 
carbon, chlorofluorocarbons, total alkalinity, pH, and salinity.  Included 
are contour plots of the various parameters and descriptions of the sampling 
techniques and analytical methods used in data collection.

KEY WORDS: alkalinity, carbon dioxide, CFC, chlorofluorocarbons, CO2, CTD, 
dissolved inorganic carbon, fugacity, hydrography, North Atlantic, nutrients, 
oxygen, pH, salinity, sigma-theta, temperature.



1.  INTRODUCTION

Human industrial and agricultural activity produces various gases such as 
carbon dioxide (CO2), chlorofluorocarbons, nitrous oxide, and methane which 
enter the atmosphere and absorb heat radiated by the earth's surface.  This 
results in a net warming of the atmosphere and creates the phenomenon 
commonly called the "greenhouse effect."  Only about half the anthropogenic 
carbon remains, however.  Many believe that the global ocean provides the 
primary sink for the "missing" CO2.  The potential climatic impact of the 
increasing concentration of these gases requires a thorough understanding of 
the absorption and storage properties of the oceans.

The National Oceanic and Atmospheric Administration's (NOAA) Ocean-Atmosphere 
Carbon Exchange Study (OACES) and Radiatively Important Trace Species (RITS) 
programs participated in a multifaceted oceanographic research cruise 
conducted aboard the NOAA ship MALCOLM BALDRIGE from July 4 to August 30, 
1993.  The objectives of the OACES component of the cruise were to determine 
the source and sink regions of CO2 in the Equatorial and North Atlantic 
during the summer and to establish a baseline of total carbon inventory in 
the region in order to measure the uptake rate of atmospheric CO2 in future 
cruises.  The objective of the RITS cruise was to evaluate the distribution 
and transport of tropospheric ozone and ozone precursors in the North 
Atlantic and was performed in association with the North Atlantic Regional 
Experiment (NARE), a component of the International Global Atmospheric 
Chemistry GGAC) Project.  This report presents only the OACES-related data 
from the cruise, including hydrography, nutrients, carbon species, dissolved 
oxygen(O2), total inorganic carbon (TCO2), chlorofluorocarbons (CFCs), total 
alkalinity (TAlk), pH, and salinity.  Biological productivity data is covered 
in the report by Michisaki et al., (1995).  The full chemical and 
hydrographic data set may be downloaded from the Atlantic Oceanographic and 
Meteorological Laboratory's (AOML) anonymous ftp site at ftp.aoml.noaa.gov 
(see Appendix B for further details).

Part I of this report contains a description of the study area and a map 
showing the cruise track.  Part 2 describes the sampling techniques and 
analytical methods used, and contains three subsections covering hydrographic 
methods, carbon parameters, and underway measurements.  The first subsection 
includes CTD, salinity, O2, nutrients, and CFC analysis methods.  Subsection 
two covers TAlk, pH, TCO2, and discrete fugacity of CO2 WOO.  The last 
subsection describes underway fCO2 measurements.  Acknowledgments and 
references are contained in Parts 3 and 4 respectively.  Contour plots of 
each parameter and various other graphs appear in Appendix A.  


1.1.  DESCRIPTION OF THE STUDY AREA

This study comprised two consecutive research cruise legs during 1993, 
repeating a section carried out by R. V. OCEANUS cruise 202 during July and 
August of 1988.  Leg 1 sailed from Fortaleza, Brazil on July 4, 1993 and, 
after a test station, proceeded to the first station at 50°S and 250°W.  From 
there the ship steamed north along the 25°W line to approximately 6°N.  The 
ship then turned NW and continued to 14°N and 29°W.  At that point 
malfunctioning boilers and the previous shutdown of the reverse osmosis 
system made the production of fresh water impossible and forced a diversion 
to Cape Verde and subsequently to Madeira.  The second leg was divided into 
two parts: Leg 2A and Leg 2B.  Leg 2A included the stations missed in Leg 1 
and departed Madeira on August 2.  After occupying a station to test all 
over-the-side systems, the ship proceeded to 34°N and 21.2°W.  There the ship 
turned W-SW and steamed to about 20°N and 29°W where it turned S, following 
the 29°W line to 16°N, occupying stations at 2° intervals.  After moving S to 
a station at 15°N the ship reversed course and retraced its route, occupying 
stations at 2° intervals and returning to Madeira on August 16.  Leg 2B left 
Madeira on August 17 and proceeded to an initial station at 35°N, 20.6°W.  
The ship then steamed northward along the 20° line to the final station at 
63.20°N and arrived in Reykjavik, Iceland on August 30, 1993.  The cruise 
tracks for Legs 1, 2A, and 2B are shown in Figure 1.



2.  DATA COLLECTION AND ANALYTICAL METHODS

During July and August 1993, a total of 83 stations were occupied between 
Fortaleza, Brazil and Reykjavik, Iceland and 94 CTD casts were made.  Thirty-
nine CTD casts occurred during Leg 1, 22 during Leg 2A, and 33 during Leg 2B.  
The CTD instrumentation consisted of three Neil Brown Instruments™ Mark 
III systems, including pressure, temperature, and conductivity sensors, and a 
General Oceanics™ 24-bottle rosette.  CTD data were recorded during the 
downcast and upcast, and discrete water samples were collected in 10-L 
Niskin™ bottles during the upcast.  Samples were collected in the 
following order: CFCs, O2, ƒCO2, TCO2, pH, TAlk, inorganic carbon-13 
(13C), nutrients, chlorophyll, phaeopigments, and salinity.  CTD casts 
were taken to within 25 m of the bottom in most cases where instrument 
problems did not preclude this (see Figure 2 for bottle trip depths and 
positions).  CTD data were acquired and processed at sea using the software 
package of Millard (1993).  Salinities and sea surface temperatures were also 
measured continuously during the entire cruise by a thermosalinograph located 
at the bow intake at 5 m depth.


2.1.  HYDROGRAPHIC METHODS

2.1.1. CTD and Hydrographic Operations

Several problems occurred with the three Neil Brown Instruments™ CTDs 
(serial numbers 1148, 2156, and 2769).  These included a noisy conductivity 
sensor, sensor drift, unrealistically high temperature offsets on isolated 
casts, bottle mistrips, problems with the new software data acquisition 
package, and deck unit troubles.  The latter required frequent swapping of 
deck units during the cruise.  At the second Madeira inport (between Legs 2A 
and 2B), a "fourth" CTD was constructed from the three originals.  Although 
it performed better, doubt was cast on the relevance of the pre-cruise 
pressurO and temperature calibrations.

During post-cruise data reduction, these problems were dealt with on a cast 
by cast basis using various methods.  For example, incorrect bottle depths 
were adjusted using a careful comparison of the bottle salinities (BOTS) and 
the CTD salinity profiles (CTDS), using knowledge of the history and trend of 
the BOTS-CTDS residuals.  On several casts where the upcast bottle trip CTD 
values failed to be logged due to software problems, downcast values were 
matched to the nominal bottle trip depths and the BOTS-CTDS residuals were 
used to confirm the match.  For the few stations exhibiting large temperature 
offsets, corrections were made based on interpolation over adjacent casts.

Despite the problems, a reasonably high quality CTD data set was obtained 
which will be useful for most scientific purposes.  Studies which by their 
nature push the limit of CTD technology and accuracy (for example, fine 
structure studies or comparative studies of long term temporal changes in 
temperature and/or salinity based on detailed comparisons with the results of 
other cruises, etc.) will probably not be possible with this data set. 
Details can be found in Table 1.

Pre-cruise laboratory calibrations were performed on the pressure and 
temperature sensors.  Typical laboratory accuracies are ±6.5 db for pressure 
and ±0.005°C for temperature.  The conductivity sensor was also calibrated in 
the laboratory, but due to the nature of the conductivity cell there is the 
possibility of at-sea calibration drift, so bottle salinities collected 
during each CTD upcast were used for the final calibration of the CTD 
salinities.

As explained above, it is not possible to quantitatively assess the accuracy 
of the temperature and pressure sensors as there was no post-cruise 
laboratory calibration available.  However, comparisons with historical data 
and checks for internal consistency such as examination of the computed 
density profiles for each CTD cast did not raise any particular doubts about 
the pre-cruise calibration values.  It is possible to quantitatively assess 
the accuracy of the conductivity sensor by comparison with the bottle 
salinities, which were accurate to within ±0.002.  The average difference was 
0.000±0.007 (n = 1942) after removing 9 outliers with difference greater 
than ±0.05.


TABLE 1. Range of salinity correction (results of polynomial):
______________________________________________________________________________________

  CTD   ΔS(0M)  ΔS(DEEP)  COMMENT
 CASTS    (1)      (2)
 -----  ------  --------  -----------------------------------------------------------
 1-16   -0.001   0.006
 17      0.009   0.004
 18     -0.004   0.002
 19-22   0       0.007
 23     -0.083  -0.05     t=t-0.173^3; computer restart
 28      0.006   0.007
 29      0.001   0.013
 30      0.013   0.015    casts 28-32: changing deck units nearly every cast
 31      0.005   0.008
 32      0.006   0.013
 33-34   0       0.003
 35     -0.343  -0.291    changed to CTD_1, 35 and 36
 36     -0.3    -0.399
 37                       (no cast 37; same location as 38) back to CTD_2 for cast 38
 38-42   0.001   0.007    no cast 4 1; at-sea memory loss
 43      0       0.009
 44-45   0.001   0.008
 46      0.021   0.024    switched to CTD 246-53
 47      0.019   0.024
 48     -0.013   0.019
 49     -0.045   0.038
 50     -0.201   0.003    t=t-0.109^3
 51     -0.083   0.032    t=t-0.109^3
 52     -0.357   0.008    t=t-0.109^3
 53     -0.2     0.091    t=t-0.109^3
 54-57   0.002   0.007    switched to CTD_4 for duration
 58     -0.041   0.009
 59-61   0.001   0.007
 62-65   0.003   0.009
 66     -0.01   -0.009
 67-70   0.004   0.01
 71      0.005   0.009
 72                       (no 72; same location as 71)
 73-79   0.005   0.009    (no 74)
 80-81   0.01    0.012
 82-84   0.005   0.01
 85-86   0.005   0.008
 87      0.005   0.01
 88      0.015   0.013
 89      0.007   0.009
 90-94   0.008   0.01     (no 93)
______________________________________________________________________________________
 Comments: 
     1. Bottle - CTD salinity upcast values (surface)
     2. Bottle - CTD salinity upcast values (deep water)
     3. Temperature correction
   

OXYGEN

Oxygen samples were collected in 150-mL ground-glass stoppered sample bottles 
and were analyzed using the method described by Carpenter, (1965), with 
computer-controlled colorimetric endpoint determination as described in 
Friederich, et al., (1984).  Analyses of Niskin™ bottles tripped at the 
same depth were used to estimate the precision.  The average deviation of 
analysis for these samples was 0.31 µmol/kg ±0.31 (n = 2 1).  The average 
deviation is defined as (∑|x(1)-x(2)|)/n where x(1) and X(2) are the measured 
oxygen concentrations for each value of duplicates and n is the number of 
duplicates.

Oxygen data were compared with data obtained on the Oceanus-202 cruise (Doney 
and Bullister, 1992; Tsuchiya et al., 1992) in order to discern any large 
scale offsets with historical deep water observations.  These comparisons led 
to the conclusion that the North Atlantic 1993 O2 values were systematically 
lower by 7.5 µmol/kg than the Oceanus-202 data for the entire cruise.  This 
offset has been observed on other cruises run by NOAA/AOML and we recommend 
adding 7.5 µmol/kg to all oxygen values in this report.  Note that the O2 data 
in this report has not been adjusted.


SALINITY

Salinity samples were collected in 200-mL bottles.  New caps were used for 
each sample.  Bottle salinities were analyzed using a Guildline™ 8400B 
Autosal standardized with Wormley standard water batch #119 in a temperature 
controlled van. Conductivity ratios were converted to salinities conforming 
to the PSS78 standard.  Analyses of NiskinTm bottles tripped at the same 
depth were used to estimate the precision.  The average deviation (as defined 
in the oxygen section above) of analysis for these samples was 0.001 ±0.001 
(n = 36).

TEMPERATURE, DENSITY AND DEPTH

Depth, potential temperature and density (σ(θ), σ(2), σ(4)) values were 
calculated using standard Woods Hole Oceanographic Institute (WHOI) 
hydrographic subroutines.  Depth was calculated from pressure using methods 
based on Saunders and Fofonoff, (1976); density was determined using the 
calculations presented in F. Millero and A. Poisson, (1981); and potential 
temperature referenced to zero pressure(theta) is calculated by integrating 
the adiabatic lapse rate using a fourth-order Runge-Kutta algorithm.

2.1.2. Nutrient Analysis

For Leg 1, two independent groups analyzed nutrients.  The AOML nutrient 
group continued for the entire cruise, while the U.W. group's data is for 
Leg 1 only.  Contour plots of nutrient concentrations are presented in two 
forms: a combination of AOML and U.W. data that uses U.W. data for Leg 1 
and AOML data for Legs 2A and 2B, and all AOML data (see Figures A-9 - A-14).  
Figures A-26, A-27, and A-28 show a comparison between the two sets of 
nutrient data.

2.1.2A. AOML Nutrients

DISOLVED NUTRIENTS

Dissolved nutrient samples were collected in aged 60-mL linear polyethylene 
bottles after three complete seawater rinses and were stored in the dark at 
4°C until analysis was completed (within 24 hours of sample collection).  
Concentrations of dissolved inorganic nitrate (NO3), nitrite (NO2), phosphate 
(PO4), and silicate (Si04), reported in μmol/kg, were determined using an 
ALPKEM™ RFA/2 Auto-Analyzer in a temperature controlled van.  The water 
used for the preparation of standards, determination of blank, and wash 
between samples was filtered Gulf Stream seawater obtained from the surface 
waters of the Straits of Florida.  At each station a 7-point standard curve 
was run prior to sample analysis.

NITRITE AND NITRATE

The automated colorimetric procedure and methodologies used in the analysis 
of nitrite and nitrate are essentially those described by Armstrong et al., 
(1967), with slight modifications described in Atlas et al., (1971).  
Standardizations were performed prior to each sample run with working 
solutions prepared aboard ship each day from pre-weighed "Baker Analyzed" 
reagent grade standards.  Nitrite (NO2) was determined by diazotizing with 
sulfanilamide and coupling with N-1 napthylethelendiamine dihydrochloride 
(NEDA) to form an azo dye.  The color produced is proportional to the nitrite 
concentration.

Samples for nitrite+nitrate (NO2+NO3) analysis were passed through a 
copperized cadmium column, which reduces nitrate to nitrite, and the 
resulting nitrite concentration was then determined as described above.  
Nitrate is the difference between nitrite+nitrate and nitrite.  The detection 
limits for nitrite and nitrate were 0.1 μmol/kg and 0.4 μmol/kg 
respectively.  Analyses of Niskin™ bottles tripped at the same depth were 
used to estimate the precision.  The average deviation (as defined in the 
oxygen section above) of analysis for these samples was 0.066 μmol/kg ±0.099 
(n = 26).

PHOSPHATE

The automated procedure for the determination of phosphate in seawater is 
described by Murphy and Riley, (1962), with modifications by Grasshoff, 
(1965).  Phosphate was determined by the reaction with an acidic molybdate 
solution.  The phosphomolybdic acid which formed was subsequently reduced 
with ascorbic acid.  The resulting molybdenum blue complex is proportional to 
the phosphate concentration in the sample.  The detection limit for phosphate 
was 0.08 μmol/kg.  Analyses of Niskin™ bottles tripped at the same depth 
were used to estimate the precision.  The average deviation (as defined in 
the oxygen section above) of analysis for these samples was 0.005 μmol/kg 
±0.007 (n = 26).

SILICATE

The analytical procedures and methodologies used in the analysis of silicate 
are those described by Armstrong et al., (1967), with modifications described 
in Atlas et al., (1971).  Silicate was determined from the reduction of 
silicomolybdate in acidic solution to molybdenum blue by stannous chloride.  
The color produced is proportional to the concentration of silicate in the 
sample.  The detection limit for silicate was 0.4 μmol/kg.  Analyses of 
Niskin™ bottles tripped at the same depth were used to estimate the 
precision.  The average deviation (as defined in the oxygen section above) of 
analysis for these samples was 0.029 μmol/kg ± 0.056 (n = 26).

2.1.2B. University of Washington Nutrients

Four nutrients (phosphate, silicate, nitrate, and nitrite) were analyzed 
using an ALPKEM™ RFA/2 rapid flow analyzer.  The methodologies used are 
found in Whitledge, et al. (1981) and adapted to the RFA/2 as indicated by 
the AlpKem method number listed below.  Primary standards were prepared in 
deionized water; working standards were prepared in low nutrient seawater.  
At each station fresh running standards were prepared, and a five point 
standard curve (adjusted to cover the entire ranges of the nutrients) was run 
prior to sample analysis.  A calibration standard was analyzed at the end of 
each sample run.  This allowed for regular monitoring of the response, drift, 
and linearity of each chemistry.

PHOSPHATE

Phosphate is converted to phosphomolybdic acid and reduced with ascorbic acid 
to form phosphomolybdous acid in a reaction stream heated to 37 °C.  The 
analytical precision as determined by replicate measurements (usually 4-6 
samples) from 9 different depths was 0.025 μmol/kg (1.09%).  (ALPKEM Method 
#A303-S200-11)

SILICATE

Silicate is converted to silicomolybdic acid and reduced with stannous 
chloride to form silcomolybdous acid.  The analytical precision as determined 
by replicate measurements (usually 4-6 samples) from 9 different depths was 
0.20 μmol/kg (0.63%).  (ALPKEM Method #A303-S220-11)

NITRITE

Nitrite is diazotized with sulfanilamide and coupled with NEDA to form a red 
azo dye.  The analytical precision as determined by replicate measurements 
(usually 4-6 samples) from 9 different depths was 0.01 μmol/kg (1%).  (ALPKEM 
Method #A303-SI80-07)

NITRATE + NITRITE

Nitrate+nitrite is measured by reducing nitrate to nitrite in a copperized Cd 
coil and then measuring for nitrite.  Nitrate is the difference between 
nitrate+nitrite and the independently measured nitrite.  The analytical 
precision as determined by replicate measurements (usually 4-6 samples) from 
9 different depths was 0.07 μmol/kg (0.24%).  (AlpKem Method # A303-S170-22)

2.1.3. CFC Analysis

Specially designed 10-L water sample bottles were used on the cruise to 
reduce CFC contamination.  These bottles have the same outer dimensions as 
standard 10-L Niskin™ bottles, but use a modified end-cap design to 
minimize the contact of the water sample with the end-cap O-rings after 
closing.  The O-rings used in these water sample bottles were vacuum-baked 
prior to the first station.  Stainless steel springs covered with a nylon 
powder coat were substituted for the internal elastic tubing normally used to 
close Niskin™ bottles.

Water samples for CFC analysis were the first samples collected from the 10-L 
bottles.  To minimize contact with air, the CFC samples were drawn directly 
through the stopcocks of the 10-L bottles into 100-mL precision glass 
syringes equipped with 2-way metal stopcocks.  The syringes were immersed in 
a holding tank of clean surface seawater until analyses.  To reduce the 
possibility of contamination from high levels of CFCs frequently present in 
the air inside research vessels, the CFC extraction/analysis system and 
syringe holding tank were housed in a modified 20' laboratory van on the deck 
of the ship.

For air sampling, a ~100 meter length of 3/8" OD Dekoron™ tubing was run 
from the CFC lab van to the bow of the ship.  Air was sucked through this 
line into the CFC van using an Air Cadet™ pump.  The air was compressed 
in the pump, with the downstream pressure held at about 1.5 atm using a back 
pressure regulator.  A tee allowed a flow (~100 mL/min) of the compressed air 
to be directed to the gas sample valves, while the bulk flow of the air (>7 
L/min) was vented through the back pressure regulator.

Concentrations of CFC-11 and CFC-12 in air samples, seawater and gas
standards on the cruise were measured by shipboard electron capture gas 
chromatography (EC-GC), using techniques similar to those described by 
Bullister and Weiss (1988).  For seawater analyses, a ~30-mL aliquot of 
seawater from the glass syringe was transferred into the glass sparging 
chamber.  The dissolved CFCs in the seawater sample were extracted by passing 
a supply of CFC-free purge gas through the sparging chamber for a period of 4 
minutes at ~70 mL/min.  Water vapor was removed from the purge gas while 
passing through a short tube of magnesium perchlorate desiccant.  The sample 
gases were concentrated on a cold-trap consisting of a 3" section of 1/8" 
stainless steel tubing packed with Porapak N (60-80 mesh) immersed in a bath 
of isopropanol held at -20°C.  After 4 minutes of purging the seawater 
sample, the sparging chamber was closed and the trap isolated.  The cold 
isopropanol in the bath was forced away from the trap which was heated 
electrically to 125°C.  The sample gases held in the trap were then injected 
onto a precolumn (12" of 1/8" OD stainless steel tubing packed with 80-100 
mesh Porasil C, held at 90°C), for the initial separation of the CFCs and 
other rapidly eluting gases from more slowly eluting compounds.  The CFCs 
then passed into the main analytical column (10', 1/8" stainless steel tubing 
packed with Porasil C 80-100 mesh, held at 90°C), and then into the EC 
detector.

The CFC analytical system was calibrated frequently using standard gas of 
known CFC composition.  Gas sample loops of known volume were thoroughly 
flushed with standard gas and injected into the system.  The temperature and 
pressure was recorded so that the amount of gas injected could be calculated.  
The procedures used to transfer the standard gas to the trap, precolumn, main 
chromatographic column and EC detector were similar to those used for 
analyzing water samples.  Two sizes of gas sample loops were present in the 
analytical system.  Multiple injections of these loop volumes could be done 
to allow the system to be calibrated over a relatively wide range of CFC 
concentrations.  Air samples and system blanks (injections of loops of CFC-
free gas) were injected and analyzed in a similar manner.  The typical 
analysis time for seawater, air, standard and blank samples was about 12 
minutes.

Concentrations of CFC-11 and CFC-12 in air, seawater samples and gas 
standards are reported relative to the S1093 calibration scale (Cunnold, et. 
al., 1994).  CFC concentrations in air and standard gas are reported in units 
of mole fraction CFC in dry gas, and are typically in the parts-per-trillion 
(ppt) range.  Dissolved CFC concentrations are given in units of picomoles of 
CFC per kg seawater (pmol/kg).  CFC concentrations in air and seawater 
samples were determined by fitting their chromatographic peak areas to multi-
point calibration curves, generated by injecting multiple sample loops of gas 
from a CFC working standard (PMEL cylinder 32386) into the analytical 
instrument.  The concentrations of CFC-11 and CFC-12 in this working standard 
were calibrated versus a secondary CFC standard (9944) before the cruise and 
a primary standard (36743) (Bullister, 1984) after the cruise.  No measurable 
drift between the working standards could be detected during this interval.  
Full range calibration curves were run 10 times during the cruise.  Single 
injections of a fixed volume of standard gas at one atmosphere were run much 
more frequently (at intervals of 1 to 2 hours) to monitor short term changes 
in detector sensitivity.

Extremely low (<0.01 pmol/kg) CFC concentrations were measured in deep water 
(>2000 meters) from about 30°N to 5°N along the section, as expected from CFC 
measurements made during the earlier occupation of this section in 1988 
(Doney and Bullister, 1992), and from other transient tracer studies made in 
this region of the eastern North Atlantic.  Based on the median of CFC 
concentration measurements in the deep water of this region, which is 
believed to be nearly CFC-free, a blank correction of 0.007 pmol/kg for CFC-
11 and 0.003 pmol/kg for CFC-12 have been applied to the data set.  For very 
low concentration water samples, subtraction of the water sample CFC blank 
from the measured CFC water sample concentration yields a small negative 
reported value.

On this expedition, we estimate precisions (1 standard deviation) of about 1% 
or 0.005 pmol/kg (whichever is greater) for dissolved CFC-11 measurements and 
2% or 0.005 pmol/kg for CFC-12 (see listing of replicate samples given in 
Tables 2 and 3).

A number of water samples (-70 out of a total of ~1700) had clearly anomalous 
CFC-11 and/or CFC-12 concentrations relative to adjacent samples.  At Station 
44, a significant number of water samples had elevated levels of CFC-12, 
believed to be due to release of CFC-12 from the ship's air conditioning 
system. Other anomalous samples appeared to occur more or less randomly 
during the cruise, and were not clearly associated with other features in the 
water column (e.g. elevated oxygen concentrations, salinity or temperature 
features, etc.).  This suggests that the high values were due to individual, 
isolated low-level CFC contamination events. These samples are included in 
this report and are given a quality flag of either 3 (questionable 
measurement) or 4 (bad measurement).  A total of 7 analyses of CFC-11 were 
assigned a flag of 3 and 9 analyses of CFC-12 were assigned a flag of 3.  A 
total of 27 analyses of CFC-11 were assigned a flag of 4 and 69 CFC-12 
samples assigned a flag of 4.


TABLE 2. NA93 Replicate dissolved CFC-11 analyses (in pmol/kg)
__________________________________________________________________________

               Replicate Number                       Replicate Number
 Stn  Samp     1      2       3        Stn  Samp      1       2      3
 ---  -----  -----  ------  ------     ---  -----  ------  ------  ------
  1     413  0.018   0.028              25   7823   1.638   1.681
  1     419  0.125   0.123              26   8018   0.775   0.778
  1     420  0.116   0.388              26   8023   1.814   1.794
  1     422  0.917   0.799              27   8603   0.003  -0.000   0.011
  1     424  1.736   1.709              27   8814   0.030   0.044
  2    1304  0.014   0.043              28   9117   0.522   0.528   0.518
  2    1308 -0.00    0.008              28   9118   0.752   0.758   0.761
  2    1318  1.752   1.678              28   9401   0.004   0.006
  3    1505  0.000   0.004              28   9418   0.772   0.780
  3    1524  1.771   1.749              29   9711   0.096   0.084
  4    1705  0.008   0.012              29   9715   0.669   0.682
  4    1709  0.051   0.041              30  10322   2.019   2.051
  4    1713  0.019   0.021  0.020       31  10516   0.191   0.184
  6    2304  0.031   0.017              31  10523   1.862   1.855
  6    2312  0.030   0.024              32  11010   0.639   0.621
  7    2424  1.743   1.790              32  11018   2.604   2.590
  9    3107  0.011   0.010              33  11409   0.134   0.138
  9    3124  1.759   1.767              33  11412   0.562   0.572
 12    3706  0.033   0.036              33  11418   2.454   2.454
 12    3724  1.754   1.744              34  12110   0.244   0.248
 14    4507  0.054   0.053              34  12121   2.467   2.429
 14    4518  1.277   1.268              35  12710   0.355   0.347
 14    4524  1.739   1.737              35  12721   2.251   2.235
 16    4808  0.012   0.016              35  12722   2.122   2.128
 16    4824  1.690   1.613              36  13006   0.001   0.004
 17    4918  1.144   1.134              36  13024   2.138   2.135
 18    5709  0.028   0.026              37  13608   0.011   0.004
 18    5724  1.649   1.674              37  13613   0.152   0.153
 19    5807  0.001   0.005              37  13619   2.338   2.335
 20    6008  0.013   0.011              38  13902  -0.001   0.010
 20    6023  1.657   1.677              38  13915   0.967   0.964
 22    6604  0.018   0.005              38  13923   2.096   2.043
 22    6606  0.019   0.004              39  14415   1.616   1.655
 22    6819  1.469   1.474              39  14421   2.108   2.129
 23    7118  0.710   0.701              40  14908  -0.002  -0.000
 23    7123  1.666   1.689  1.633       44  16801   0.007   0.002
 24    7618  0.675   0.669              44  16805  -0.006   0.000
 24    7619  0.882   0.885              45  17002  -0.006  -0.000
 25    7812  0.007   0.002              45  17010   0.001  -0.00
 25    7818  0.775   0.775              46  17205  -0.001   0.000


               Replicate Number                       Replicate Number
 Stn  Samp     1      2       3        Stn  Samp      1       2      3
 ---  -----  -----  ------  -----      ---  -----  ------  ------  ------
 47   17703  0.000  -0.005              63  23304   0.208   0.208
 47   17710  0.001  -0.004              63  23322   3.245   3.230
 48   18302 -0.002  -0.004              64  23909   1.745   1.766
 48   18303 -0.002  -0.003              64  23915   2.800   2.783
 48   18314  0.553   0.558              64  23920   3.145   3.144
 48   18316  1.889   1.873              65  24206   0.636   0.641
 49   18618  2.388   2.409              65  24210   2.017   2.010
 49   18622  2.153   2.168              66  24717   3.361   3.337
 50   19103 -0.002   0.000  0.001       68  25322   3.340   3.303
 50   19112  0.179   0.174              69  25417   3.393   3.424
 51   19604  0.000   0.001              69  25422   3.085   3.064
 51   19611  0.218   0.216              71  25722   3.234   3.243
 51   19613  0.758   0.763              71  25724   3.102   3.116
 51   19615  2.060   2.066              72  26223   2.973   3.002
 52   19805  0.006   0.010              74  26821   3.684   3.748
 52   19821  2.412   2.478              75  27305   2.335   2.302
 53   20405  0.004   0.002              75  27315   3.447   3.571
 53   20409  0.228   0.225              78  28308   2.198   2.188
 53   20421  2.748   2.661              78  28314   3.438   3.788
 54   20605  0.019   0.020              78  28320   3.810   3.644
 54   20610  0.471   0.480              80  28718   3.587   3.581
 56   21609  0.546   0.534              81  28814   3.917   3.916
 56   21622  2.883   2.836              81  28820   3.859   3.890
 60   22716  3.218   3.218              81  28823   3.779   3.790
 61   23109  1.633   1.646              83  29108   4.030   3.981
__________________________________________________________________________



TABLE 3. NA93 Replicate dissolved CFC-11 analyses (in pmol/kg)

________________________________________________________________________________

                    Replicate Number      |                Replicate Number
 Stn  Samp      1       2      3      4   | Stn  Samp      1       2       3
 ---  -----  ------  ------  -----  ----- | ---  -----  ------  ------  -------
   1    413   0.010   0.012               |  38  13902   0.003   0.003
   1    419   0.076   0.077               |  38  13915   0.496   0.518
   1    422   0.448   0.424               |  38  13923   1.148   1.120
   1    424   0.976   0.978               |  39  14415   0.816   0.869
   2   1308  -0.003   0.003               |  39  14421   1.170   1.205
   2   1313   0.440   0.441               |  40  14908   0.000   0.002
   2   1318   0.980   0.943               |  44  16805   0.003  -0.002
   3   1505   0.004   0.000               |  45  17002  -0.003  -0.003
   4   1705   0.010   0.006               |  45  17010  -0.003   0.000
   4   1709   0.021   0.017  0.022        |  46  17205   0.000   0.000
   4   1713   0.010   0.010  0.012        |  47  17703  -0.001  -0.003
   4   1724   0.933   0.933               |  47  17710  -0.003  -0.005
   6   2304   0.011   0.038               |  48  18302   0.004   0.000
   6   2312   0.014   0.010               |  48  18303  -0.002  -0.001
   9   3107   0.006   0.004               |  48  18316   0.936   0.992
   9   3124   0.985   0.988               |  49  18618   1.234   1.252
  12   3706   0.023   0.030               |  49  18622   1.156   1.164
  12   3724   0.973   0.990               |  50  19103  -0.001  -0.0020  -0.002
  14   4507   0.029   0.034               |  50  19112   0.095   0.086
  14   4518   0.695   0.644               |  51  19604   0.001   0.000
  14   4524   0.967   0.970               |  51  19611   0.107   0.117
  16   4808   0.008   0.017               |  51  19613   0.376   0.398
  16   4824   0.943   0.906               |  51  19615   1.053   1.050
  17   4918   0.601   0.602               |  52  19805   0.000   0.006
  18   5709   0.015   0.025               |  52  19821   1.322   1.353
  18   5724   0.946   0.963               |  53  20405   0.004   0.007
  20   6023   0.917   0.972               |  53  20409   0.128   0.130
  22   6606   0.004   0.005               |  53  20421   1.443   1.400
  23   7123   1.032   0.967               |  54  20605   0.011   0.015
  24   7618   0.393   0.366               |  54  20610   0.249   0.227
  24   7619   0.471   0.478               |  56  21609   0.271   0.280
  25   7812   0.000  -0.001               |  56  21622   1.527   1.479
  25   7818   0.432   0.427               |  60  22716   1.586   1.635
  25   7823   0.915   0.942               |  61  23109   0.793   0.769
  26   8018   0.421   0.418               |  63  23322   1.627   1.640
  26   8023   1.014   1.020               |  64  23909   0.780   0.813
  27   8814   0.027   0.025               |  64  23915   1.353   1.312
  28   9117   0.302   0.302  0.306        |  64  23920   1.537   1.534
  28   9118   0.416   0.414  0.403        |  65  24206   0.327   0.324
  28   9401   0.015   0.014               |  65  24210   0.932   0.935
  28   9418   0.433   0.432               |  66  24702   0.024   0.019
  29   9711   0.056   0.062               |  66  24717   1.713   1.697
  29   9715   0.379   0.397               |  68  25322   1.726   1.723
  30  10322   1.109   1.132               |  69  25417   1.722   1.771
  31  10516   0.118   0.118               |  69  25422   1.578   1.587
  32  11010   0.329   0.325               |  71  25722   1.654   1.682
  32  11018   1.365   1.368               |  71  25724   1.622   1.626
  33  11408   0.054   0.064               |  72  26223   1.572   1.576
  33  11418   1.287   1.331               |  74  26821   1.902   1.940
  34  12110   0.149   0.149               |  75  27305   1.139   1.120
  34  12121   1.348   1.347               |  75  27315   1.744   1.807
  35  12710   0.210   0.200               |  78  28308   1.069   1.059
  35  12721   1.219   1.238               |  78  28314   1.737   1.973
  35  12722   1.195   1.187               |  78  28320   1.868   1.894
  36  13006  -0.003   0.005               |  80  28718   1.838   1.836
  36  13024   1.177   1.175               |  81  28814   2.056   2.010
  37  13608   0.001   0.003               |  81  28820   2.003   2.004
  37  13613   0.077   0.076               |  81  28823   1.968   1.980
  37  13619   1.271   1.271  1.248  1.268 |  83  29108   2.091   2.054
________________________________________________________________________________



TABLE 4. NA93 CFC air measurements for Leg 1
         __________________________________________________________
         
            Date     Time  Latitude  Longitude  F11(PPT)  F12(PPT)
          ---------  ----  --------  ---------  --------  --------
           5-Jul-93  1624  04 10.6S  033 19.6    261.5     514.6
           5-Jul-93  1708  04 10.6S  033 19.6    261.9     515.3
           5-Jul-93  1722  04 10.6S  033 19.6    260.2     515.7
           8-Jul-93   606  04 03.3S  024 59.5     -9.0      -9.0
           8-Jul-93  1158  03 42.9S  025 00.1    262.7     509.7
           8-Jul-93  1211  03 42.9S  025 00.1    262.6     508.0
           8-Jul-93  1226  03 42.9S  025 00.1    262.6     507.6
           8-Jul-93  1239  03 42.9S  025 00.1    263.6     509.0
           9-Jul-93   712  03 42.9S  025 00.1    262.3     510.8
           9-Jul-93   725  03 42.9S  025 00.1    262.7     510.0
           9-Jul-93   754  02 10.9S  025 00.4    263.4     510.3
           9-Jul-93   809  02 10.9S  025 00.4    264.1     510.3
           9-Jul-93   824  02 10.9S  025 00.4    263.1     509.4
          10-Jul-93  2246  01 08.6S  025 00.8    263.4     508.0
          1O-Jul-93  2258  01 08.6S  025 00.8    263.5     504.9
          1O-Jul-93  2312  01 08.6S  025 00.8    263.3     506.3
          12-Jul-93  1450  04 48.8   026 04.5    264.7      -9.0
          12-Jul-93  1504  04 48.8   026 04.5    264.5     511.2
          12-Jul-93  1517  04 48.8   026 04.5     -9.0      -9.0
          13-Jul-93   144  04 48.8   026 04.5     -9.0      -9.0
          13-Jul-93   157  04 48.8   026 04.5     -9.0      -9.0
          13-Jul-93   210  04 48.8   026 04.5     -9.0      -9.0
          13-Jul-93  2112  09 00.0   027 00.0    261.2     507.7
          13-Jul-93  2125  09 00.0   027 00.0    261.3     504.8
          13-Jul-93  2141  09 00.0   027 00.0    260.7     503.0
          13-Jul-93  2160  09 00.0   027 00.0    264.4     512.0
          14-Jul-93  1811  10 46.4   028 03.1    264.3     513.0
          14-Jul-93  1825  10 46.4   028 03.1   -264.1     515.0
          14-Jul-93  1838  10 46.4   028 03.1    263.9     514.9
          14-Jul-93  1852  10 46.4   028 03.1    264.9     514.6
          15-Jul-93  1200  11 52.1   028 27.9    267.9      -9.0
          15-Jul-93  1227  11 52.1   028 27.9    265.9     521.4
          15-Jul-93  1252  11 52.1   028 27.9    268.8     521.4
          15-Jul-91   318  11 52.1   028 27.9    266.5     518.4
          17-Jul-93   122  15 00.3   028 17.0    265.7     517.6
          17-Jul-93   135  15 00.3   028 17.0    268.3     515.7
          17-Jul-93   155  15 00.3   028 17.0    266.7     517.5
          17-Jul-93   209  15 00.3   028 17.0    268.8     516.9
          17-Jul-93  1645  16 45.1   025 19.7    267.0     523.8
          17-Jul-93  1659  16 45.1   025 19.7    266.5     521.2
          17-Jul-93  1725  16 45.1   025 19.7    267.6     521.9
          17-Jul-93  1741  16 45.1   025 19.7    267.0      -9.0
         __________________________________________________________



TABLE 5. NA93 CFC air measurements for Leg 2
         __________________________________________________________
         
            Date     Time  Latitude  Longitude  F11(PPT)  F12(PPT)
          ---------  ----  --------  ---------  --------  --------
           2-Aug-93   928  33 45.9   020 31.7    266.8     515.2
           2-Aug-93   940  33 45.9   020 31.7    267.1     519.0
           2-Aug-93   953  33 45.9   020 31.7    267.7     520.8
           3-Aug-93  1233  32 00.0   022 24.2    266.6     517.1
           3-Aug-93  1259  32 00.0   022 24.2    267.5     514.9
           4-Aug-93   354  29 44.1   023 41.6    264.2     515.8
           4-Aug-93   408  29 44.1   023 41.6    264.6     513.1
           4-Aug-93   422  29 44.1   023 41.6    265.0     512.6
           5-Aug-93   858  25 59.2   025 46.5    264.9     521.3
           5-Aug-93   911  25 59.2   025 46.5    266.5     524.1
           5-Aug-93   923  25 59.2   025 46.5    266.4     521.8
           6-Aug-93  1447  21 50.6   028 01.4    264.5     519.9
           6-Aug-93  1460  21 50.6   028 01.4    265.9     519.0
           6-Aug-93  1513  21 50.6   028 01.4    264.8     519.8
           8-Aug-93  1044  19 58.7   029 02.2    267.5     519.3
           8-Aug-93  1056  19 58.7   029 02.2    268.6     519.3
           8-Aug-93  1108  19 58.7   029 02.2    266.9     520.6
           9-Aug-93  1717  14 59.2   029 00.2    262.4     523.6
           9-Aug-93  1742  14 59.2   029 00.2    264.1     512.8
          11-Aug-93  1333  23 00.0   027 26.1    267.7     524.3
          11-Aug-93  1345  23 00.0   027 26.1    270.2     524.2
          11-Aug-93  1358  23 00.0   027 26.1    267.5     523.5
          12-Aug-93  1407  26 38.7   025 26.5    265.9     523.0
          12-Aug-93  1420  26 38.7   025 26.5    266.5     524.2
          12-Aug-93  1433  26 38.7   025 26.5    266.0     524.0
          13-Aug-93    11  27 38.6   024 53.0    271.7     521.0
          13-Aug-93    24  27 38.6   024 53.0    269.7     517.4
          13-Aug-93    37  27 38.6   024 53.0    270.0     516.7
          13-Aug-93  1225  28 59.7   024 07.5    266.3     521.0
          13-Aug-93  1238  28 59.7   024 07.5    266.5     518.2
          13-Aug-93  1251  28 59.7   024 07.5    266.4     521.2
          20-Aug-93  2203  41 00.0   020 00.0    271.2     523.6
          20-Aug-93  2215  41 00.0   020 00.0    269.0     530.1
          22-Aug-93  2042  45 58.0   020 00.0    266.2     521.1
          22-Aug-93  2055  45 58.0   020 00.0    267.0     524.9
          22-Aug-93  2108  45 58.0   020 00.0    265.1     515.6
          25-Aug-93   750  52 00.0   020 00.0    266.2     516.6
          25-Aug-93   803  52 00.0   020 00.0    267.4     523.7
          25-Aug-93   815  52 00.0   020 00.0    272.7     514.8
          29-Aug-93    51  62 59.2   019 59.9    265.3     517.5
          29-Aug-93   104  62 59.2   019 59.9    266.5     518.7
          29-Aug-93   117  62 59.2   019 59.9    267.3     518.5
         __________________________________________________________
         
         

TABLE 6. NA93 CFC Air values (interpolated to station locations)
         __________________________________________________________
         
            Date     Time  Latitude  Longitude  F11(PPT)  F12(PPT)
          ---------  ----  --------  ---------  --------  --------
           2-Aug-93   928  33 45.9   020 31.7    266.8     515.2
           2-Aug-93   940  33 45.9   020 31.7    267.1     519.0
           2-Aug-93   953  33 45.9   020 31.7    267.7     520.8
           3-Aug-93  1233  32 00.0   022 24.2    266.6     517.1
           3-Aug-93  1259  32 00.0   022 24.2    267.5     514.9
           4-Aug-93   354  29 44.1   023 41.6    264.2     515.8
           4-Aug-93   408  29 44.1   023 41.6    264.6     513.1
           4-Aug-93   422  29 44.1   023 41.6    265.0     512.6
           5-Aug-93   858  25 59.2   025 46.5    264.9     521.3
           5-Aug-93   911  25 59.2   025 46.5    266.5     524.1
           5-Aug-93   923  25 59.2   025 46.5    266.4     521.8
           6-Aug-93  1447  21 50.6   028 01.4    264.5     519.9
           6-Aug-93  1460  21 50.6   028 01.4    265.9     519.0
           6-Aug-93  1513  21 50.6   028 01.4    264.8     519.8
           8-Aug-93  1044  19 58.7   029 02.2    267.5     519.3
           8-Aug-93  1056  19 58.7   029 02.2    268.6     519.3
           8-Aug-93  1108  19 58.7   029 02.2    266.9     520.6
           9-Aug-93  1717  14 59.2   029 00.2    262.4     523.6
           9-Aug-93  1742  14 59.2   029 00.2    264.1     512.8
          11-Aug-93  1333  23 00.0   027 26.1    267.7     524.3
          11-Aug-93  1345  23 00.0   027 26.1    270.2     524.2
          11-Aug-93  1358  23 00.0   027 26.1    267.5     523.5
          12-Aug-93  1407  26 38.7   025 26.5    265.9     523.0
          12-Aug-93  1420  26 38.7   025 26.5    266.5     524.2
          12-Aug-93  1433  26 38.7   025 26.5    266.0     524.0
          13-Aug-93    11  27 38.6   024 53.0    271.7     521.0
          13-Aug-93    24  27 38.6   024 53.0    269.7     517.4
          13-Aug-93    37  27 38.6   024 53.0    270.0     516.7
          13-Aug-93  1225  28 59.7   024 07.5    266.3     521.0
          13-Aug-93  1238  28 59.7   024 07.5    266.5     518.2
          13-Aug-93  1251  28 59.7   024 07.5    266.4     521.2
          20-Aug-93  2203  41 00.0   020 00.0    271.2     523.6
          20-Aug-93  2215  41 00.0   020 00.0    269.0     530.1
          22-Aug-93  2042  45 58.0   020 00.0    266.2     521.1
          22-Aug-93  2055  45 58.0   020 00.0    267.0     524.9
          22-Aug-93  2108  45 58.0   020 00.0    265.1     515.6
          25-Aug-93   750  52 00.0   020 00.0    266.2     516.6
          25-Aug-93   803  52 00.0   020 00.0    267.4     523.7
          25-Aug-93   815  52 00.0   020 00.0    272.7     514.8
          29-Aug-93    51  62 59.2   019 59.9    265.3     517.5
          29-Aug-93   104  62 59.2   019 59.9    266.5     518.7
          29-Aug-93   117  62 59.2   019 59.9    267.3     518.5
         __________________________________________________________


2.2. CARBON PARAMETERS

2.2.1. Total Dissolved Inorganic CO2 (TCO2)

SAMPLING

Samples were drawn from 10-L Niskin™ bottles into 0.5-L Pyrex™ bottles using 
Tygon™ tubing.  Bottles were rinsed once and filled from the bottom, overflowing 
half a volume while taking care not to entrain any bubbles.  The tube was 
pinched off and withdrawn, creating a 5 mL headspace volume.  0.2 mL of 
saturated mercuric chloride (HgCl(2)) solution was added as a preservative.  The 
sample bottles were sealed with glass stoppers lightly covered with Apiezon-L™ 
grease.  The samples were stored at room temperature in the dark for a maximum 
of two days.

ANALYSIS

The TCO2 analyses were performed by extracting the inorganic carbon in a 
seawater sample by acidification and subsequent displacement of the gaseous 
CO2 into a coulometer cell.  Two coulometers were used on the cruise.  Both 
were equipped with a SOMMA (Single Operator Multiparameter Metabolic 
Analyzer) inlet system developed by Ken Johnson of Brookhaven National 
Laboratory (BNL).  The first system, "AOML-1" was previously used on the NOAA 
S-Atl-91 and EqPac-92 cruises (Forde et al., 1994; Lantry et al., 1995).  The 
second system, "AOML-2", was brought into service in February 1993 and this 
was its first use at sea.

For analysis on the SOMMA system, a 0.5 L sample bottle was inserted in a 
water bath at 20°C.  Water from the bottle was displaced by pressurization 
into a thermostated pipette using a (700 parts per million by volume 
(ppm)CO2 in air) gas.  The sample was injected into an extraction chamber 
which contained 1 mL 10% H(3)PO4 solution previously stripped of CO2.  The 
evolved CO gas from the sample was run through a condenser and a magnesium 
perchlorate drying column to dry the gas stream, and through an ORBO-
53™ tube to remove volatile acids, using a carrier stream of CO2-free 
ultra high purity nitrogen.  In the coulometer cell the CO2 is absorbed by a 
proprietary solution procured from Utopia Instrument Company (UIC).  This 
solution changes color from blue to colorless by addition of the (acid) CO2 
gas.  A photodiode detects the color change and causes a current to pass 
through the cell with electrolytic production of hydroxide ions at the 
cathode.  The titration current is turned off when the solution reaches the 
original color.  The current passed through the cell is measured by a counter 
and is directly proportional to the amount of CO2 injected.  The details of 
the system can be found in Johnson, (1992) and Johnson et al., (1993).  The 
coulometer cell solution was replaced after 30 mg of carbon was titrated or 
when the coulometer runs were less then 9 minutes.  This typically was after 
18-20 hours of continuous use.  Typical sample titration times were 9 to 16 
minutes.

Both coulometers were calibrated by injecting aliquots of pure CO2 using an 
8-port valve with two sample loops.  The CO2 gas volumes bracketed the 
amount of CO2 extracted from the water samples for the two AOML systems.  The 
gas loops were calibrated at BNL.  Liquid certified reference materials 
(CRMs) consisting of poisoned, filtered, and UV irradiated seawater supplied 
by Dr. A. Dickson of Scripps Institution of Oceanography (SIO) were run on 
each cell.  The results were close to the values determined manometrically by 
Keeling at SIO as shown below.

     Av. value of CRMs run on AOML-1: 2033.46 μmol/kg ± 1.15      n = 55
     Av. value of CRMs run on AOML-2: 2032.86 μmol/kg ± 0.96      n = 51

The manometric value (SIO reference material batch #16) was 2034.54 
μmol/kg±0.91 n = 9.

Note: Only the first replicate of the analyses, which were run early in 
      coulometer cells, were used for the averages.


Replicate seawater samples were taken from the deepest Niskin™ sample and run at 
different times during the cell. The first replicate was used at the start of 
the cell with fresh coulometer solution, the second at the end of the cell after 
about 30 mg of C were titrated, while the third analysis was performed using a 
new coulometer cell solution. No systematic difference between the replicates 
was observed. As example, the replicate samples run on SOMMA AOML-I had an 
average absolute difference from the mean of 1 μmol/kg with a standard 
deviation of 1.9 μmol/kg for 40 sets of triplicates. The deviation is very 
similar to that observed for the CRMs and suggest no strong dependency of 
results with amount of carbon titrated for a particular cell.

The data of the two instruments were normalized using the averages of the 
reference material for the cruise.  The following corrections were applied to 
the data: AOML-1, + 1.08 μmol/kg; AOML-2, + 1.68 μmol/kg.

CALCULATIONS

The instruments were calibrated three times during each cell solution with a 
set of CO2 gas loop injections.  Calculation of the amount of CO2 injected 
was according to the Department of Energy (DOE) CO2 handbook (DOE, 1994).  
The gas loops yielded a calibration factor for the instrument defined as:

        Cal. factor = calculated moles of CO2 injected from gas loop
        ------------------------------------------------------------      (1)
                        actual moles of CO2 injected

The concentration of CO2 ([CO2]) in the samples was determined according to:

                           (Counts - Blank * Run Time) * K μmol/count
      [CO2] = Cal. factor* ------------------------------------------     (2)
                               pipette volume * density of sample

where "Counts" is the instrument reading at the end of the analysis, "Blank" 
is the counts/minute determined from blank runs performed at least once for 
each cell of the solution, "Run Time" is the length of coulometric titration 
(in minutes), and K is the conversion factor from counts to μmol which is 
dependent on the slope and intercept relation between instrument response and 
charge.  For a unit with slope of 1 and intercept of 0, the constant is 
2.0728 * 10^(-4) μmol/count.

The pipette volume was determined by taking aliquots at known temperature of 
distilled water from the volumes prior to, during, and after the cruise.  The 
weights with the appropriate densities were used to determine the volume of 
the syringes and pipette.  Calculation of pipette volumes, density, and final 
CO2 concentration were performed according to procedures outlined in the DOE 
CO2 handbook (DOE, 1994).

Based on weighings of distilled water aliquots the volume of the AOML-1 
pipette was 28.715 mL (20°C, 1 atm) with a standard deviation of 0.013 mL.  
The pipette volume of AOML-2 was 27.177 mL with a standard deviation of 0.014 
mL.  Assuming that the standard deviation represents the uncertainty in the 
delivery to the extraction chamber this accounts for approximately 90% of the 
variance in the CRM value.

All TCO2 values are corrected for dilution by 0.2 mL of mercuric chloride 
solution assuming the solution is saturated with atmospheric CO2 levels and 
total water volume in the sampling bottles is 540 mL.  The correction factor 
used is 1.00037.  This is in addition to the correction to the CRM values for 
AOML-1 of + 1.08 μmol/kg and for AOML-2 of + 1.68 μmol/kg as listed above.

2.2.2 Discrete Fugacity of CO2 (fCO2)(1)

SAMPLING

Samples were drawn from 10-L Niskin™ bottles into 500 mL Pyrex™ volumetric 
flasks using Tygon™ tubing. Bottles were rinsed once and filled from the bottom, 
overflowing half a volume while taking care not to entrain any bubbles. Five mL 
of water was withdrawn with a pipette to create a small expansion volume. 0.2 mL 
of saturated HgCl(2) solution was added as a preservative. The sample bottles 
were sealed with a screw cap containing a polyethylene liner. The samples were 
stored upside down at room temperature for a maximum of one day.

ANALYZER DESCRIPTION

The discrete ƒCO2 system is patterned after the setup described in Chipman, 
et al., (1993) and is discussed in detail in Wanninkhof and Thoning (1993) 
and Chen, et al., (1995).  The major difference between the systems is that 
our system uses a LICOR™ model 6262 non-dispersive infrared (IR) analyzer, while 
the system of Chipman, et al. (1993) utilizes a gas chromatograph with a flame 
ionization detector and a methanizer that quantitatively converts CO2 into CH4 
for analysis.

Samples collected in 500-mL volumetric flasks are brought to a temperature of 
20.00 ±0.02°C, by first inserting the flasks upside down in a pre-bath at 19-
21°C, and subsequently in a Neslab™ model RT-220 controlled temperature 
bath for equilibration and analysis.  A 60-mL headspace is created in the 
sample flask by displacing the water using a compressed standard gas with 
a CO2 mixing ratio close to the ƒCO2 of the water.  The headspace is circulated 
in a closed loop through the infrared analyzer which measures CO2 and water 
vapor levels in the sample cell.  The headspaces of two flasks are equilibrated 
simultaneously in two separate channels.

___________________________________
(1) The fugacity of CO2 (ƒCO2) is the partial pressure of CO2 corrected for 
    non-ideality of CO2 in air.  At ambient temperature, fCO2 - 0.995* PCO2.





While headspace from the flask in the first channel goes through the IR 
analyzer, the headspace of the flask in the second channel is recirculated in 
a closed loop.  After the first sample is analyzed a valve is switched to put 
the second channel in line with the analyzer.  The samples are equilibrated 
till the running mean of twenty consecutive 1-second readings from the 
analyzer differ by less than 0.1 ppm, which on average takes about 10 
minutes.  An expandable volume consisting of a balloon keeps the content of 
flasks at room pressure.

In order to maintain measurement precision, a set of six gas standards is run 
through the system after every 8 to 12 seawater samples.  The standards have 
mixing ratios of 201.4, 354.1, 517.0, 804.5, 1012.2, and 1515 ppm which 
bracket the fCO2 at 20°C (fCO2(20)) values observed in the water column.

The determination of ƒCO2(20) in water from the headspace measurement 
involves several steps.  The IR detector response for the standards is 
normalized for temperature, the IR analyzer voltage output for samples is 
normalized to 1 atm pressure, and the IR detector response is corrected for 
the influence of water vapor.  The sample values are converted to a mixing 
ratio based on the compressed gas standards.  The mixing ratio in the 
headspace is converted to fugacity and corrected to fugacity of CO2 in the 
water sample prior to equilibration by accounting for change in total CO2 in 
water during the equilibration process (for details see Wanninkhof and 
Thoning, (1993)).  The change in ƒCO2(20) caused by the change in TCO2 
is calculated using the constraint that TAlk remains constant during 
exchange of CO2 gas between the headspace and the water.  The calculation is 
outlined in the appendix of Peng et al., (1987).

Relative errors for ƒCO2 analysis for the North Atlantic 1993 cruise were 
determined from duplicates taken from the same Niskin™ bottle (Table 7).  
The deviation is defined as: (difference in duplicates/(2*mean)*100) and is 
expressed both in parts per million by volume (ppm) and in percent.


TABLE 7. fCO2 Measurement Error
         _________________________________________________________
         
                                                      Deviation
          Leg  Sta.  Sample  Pressure  Temp   fCO2    ppm     %
          ---  ----  ------  --------  -----  -----   -----  ----
           1    2     1302    3152.4    2.40  749.1   0.9    0.11
           1    2     1303    2600.8    2.69  762.2   2.4    0.32
           1    6     2303    4651.3    0.46  961.3   4.5    0.47
           1   16     4824       0.2   27.14  263.9   0.6    0.22
           1   19     5803    3803.2    2.07  764.2   4.3    0.56
           1   29     9721      20.5   26.86  266.0   1.8    0.68
           1   29     9722       0.0   27.13  272.5   0.9    0.32
           1   30    10303    5000.8    1.82  772.2   1.5    0.20
          2A   32    11010    1000.4    9.09  687.7   0.9    0.13
          2A   32    11023       0.0   22.03  331.2   0.2    0.06
          2A   40    14903    3999.1    2.04  759.2   1.1    0.15
          2A   40    14923      19.7   24.37  296.5   0.5    0.17
          2A   44    16822       3.0   24.45  304.2   0.2    0.06
          2A   48    18320      99.7   19.87  332.6   1.7    0.52
          2B   57    21703    4010.7    2.20  758.0   1.1    0.15
          2B   57    21704    3507.7    2.35  753.6   0.8    0.11
          2B   59    22522      19.2   19.87  341.3   0.2    0.05
          2B   61    23122      25.2   19.77  340.5   0.1    0.02
          2B   76    27503    1196.1    4.62  770.8   0.2    0.03
          2B   76    27517     250.1    9.43  599.0   0.6    0.10
                                                   --------  ----
                                                   average%  0.22
         _________________________________________________________


2.2.3. Total Alkalinity and pH

pH MEASUREMENTS

The pH measurements of seawater were made using the spectrophotometric
techniques of Clayton and Byrne (1993).  The pH of samples using the m-cresol 
purple (mCP) is determined from:

              pH = pK(ind) + log[(R - 0.0069)/(2.222 - 0.133 R)]          (3)

where K(ind) is the dissociation constant for the indicator and R 
(A(578)/A(434))is the ratio of the absorbance of the acidic and basic forms 
of the indicator corrected for baseline absorbance at 730 nm.  The pH of the 
samples is perturbed by the addition of an indicator.  The magnitude of this 
perturbation is a function of the difference between the seawater acidity and 
indicator acidity; therefore this correction was quantified for each batch of 
dye solution.  To a sample of seawater (~30 mL), a normal volume of mCP 
(0.080 mL, in this case) was added and the absorbance ratio was measured.  
From a second addition of mCP and absorbance ratio measurement, the change in 
absorbance ratio per mL of added indicator (ΔR) was calculated.  From a 
series of such measurements over a range of seawater pH, ΔR was described as 
a linear function of the value of the absorbance ratio (R(m)) measured 
subsequent to the initial addition of the indicator (i.e. R = 0.02959 - 
0.1288 R(m)).  In the course of routine seawater pH analyses, this correction 
was applied to every measured absorbance ratio (Rm); i.e. the corrected 
absorbance ratio is calculated as

                    R = R(m) + (0.02959 - 0.1288 R(m))                   (4)

Clayton and Byrne (1993) calibrated the m-cresol purple indicator using TRIS 
Buffers (Ramette et al., 1977) and the pH equations of Dickson (1993).  They 
found that

           pK(ind)= 1245.69/T + 3.8275 + (2. 11 x 10^(-3))(35-S)          (5)

where T is temperature in Kelvin and is valid from 293.15 to 303.15 K and S = 
30 to 37.  The values of pH calculated from equations (3) and (5) are on the 
total scale in units of mol/(kg-soln).  The total proton scale (Hansson, 
1973) defines pH in terms of the sum of the concentrations of free hydrogen 
ion, [H+], and bisulfate, [HS0(4)^-]

                    pH(T) = -log[H+](T) 
                          = -log{[H+]+[HS04^-]}                           (6)
                          = -log[H+](1+[SO(4)^2-]/k(HSO(4)  

where the concentration of total sulfate, [S04^(2-)] = 0.0282 x 35/S and 
K(HS04) is the dissociation constant for the bisulfate in seawater (Dickson, 
1990a).

We have redetermined the value of PK(ind) from 273.15 to 313.15 K using a 
0.04 M TRIS buffer (Ramette et al., 1977).  The pH of the TRIS buffer was 
determined from the emf measurements made with the H2,Pt| AgCI,Ag electrode 
system (Millero et al., 1993a).  At 25°C the buffer had a pH of 8.076 and 
yielded spectrophotometric values of pH that were in excellent agreement 
(~0.0001) with those found using equations (3) and (5).  Our results from 
273.15 to 313.15 K (0 to 40°C) were fitted to the equation (S = 35)

               pK(ind) = 35.913 - 216.404/T - 10. 9913 log (T)            (7)

with the standard error of 0.001 in PK(ind) where the constants are on the 
total proton scale {mol/(kg-H20).  The use of equation (3) and (7) from 0 to 
40°C makes the assumption that R is independent of the temperature.

The values of pH calculated from equation (3) and (7) are on the total scale 
in units of mol/(kg-H20).  The conversion of the pH(T) {mol/(kg-H20)) to the 
seawater pH(SWS) {mol/(kg-soln)) can be made using (Dickson and Riley, 1979; 
Dickson and Millero, 1987):

         pH(SWS) = pH(T) - log{(l + [S04^(2-)]/K(HSO4) + [F]/K(HF))/
                   (1 + [SO4^(2-)]/K(HSO4)} - log(1 - 1.005 x 10^(-3)S)   (8)


where the total concentration of fluoride, [F^-] = 0.000067 x 35/S, and 
K(HF) is the dissociation constant for hydrogen fluoride (Dickson and Riley, 
1979).  The seawater pH(SWS) scale was used here since the carbonate 
constants used are on this scale (Dickson and Millero, 1987; Millero et al., 
1993b).

The absorbance measurements were made using a HP™ Diode Array 8452 A 
spectrophotometer.  The temperature was controlled to 20°C with an 
Endocal™ RTE 8DD refrigerated circulating temperature bath that regulates 
the temperature to ±0.01°C.  The temperature was measured using a 
Guildline™ 9540 digital platinum resistance thermometer.


TOTAL ALKALINITY MEASUREMENTS, TAlk

TITRATION SYSTEM

The titration systems used to determine TAlk consisted of a Metrohm™ 665 
Dosimat titrator and an Orion™ 720A pH meter that is controlled by a 
personal computer (Millero et al., 1993c).  Both the acid titrant in a water-
jacketed burette and the seawater sample in a water-jacketed cell were 
controlled to a constant temperature of 25 ±0.1°C with a Neslab™ constant 
temperature bath.  The Plexiglass™ water jacketed cells used during the cruise 
were similar to those used by Bradshaw and Brewer (1988) except a larger 
volume (about 200 mL) was used to increase the precision.  This cell had a 
fill and drain valve, which increased the reproducibility of the cell volume.

A GWBASIC™ program used to run the titration records the volume of the 
added acid and the emf of the electrodes using RS232 interfaces.  The 
titration is made by adding HCl to seawater past the carbonic acid end point.  
A typical titration records the emf reading after the readings become stable 
(±0.09 mV) and adds enough acid to change the voltage to a pre-assigned 
increment (13 mV).  In contrast to the delivery of a fixed volume increment 
of acid, this method gives data points in the range of a rapid increase in 
the emf near the endpoint.  A full titration (25 points) takes about 20 
minutes.  Using three systems a 24-bottle station cast was completed in 3.5 
hours.

ELECTRODES

The electrodes used to measure the emf of the sample during a titration 
consisted of a ROSS™ glass pH electrode and an Orion™ double junction 
Ag, AgCl reference electrode.

STANDARD ACIDS

The HCl used throughout the cruise was made, standardized, and stored in 500 
mL glass bottles in the laboratory for use at sea.  The 0.2526 M HCl 
solutions were made from 1 M Mallinckrodt™ standard solutions in 0.45 M 
NaCl to yield an ionic strength equivalent to that of average seawater (~0.7 
M).  The acid was standardized using a coulometric technique by Millero's 
group (RSMAS) and Dickson's group (Taylor and Smith, 1959; Marinenko and 
Taylor, 1968). Both results agree to ±0.0001 N.

VOLUME OF THE CELLS

The volumes of the cells were determined in the laboratory by making weight 
titrations of Gulf stream seawater (S - 36).  The TAlk of this water was 
determined by making a number of titrations.  The volume was determined by 
comparing the values of TAlk obtained for Gulf stream seawater with open 
(weighed amount of seawater) and closed cells NMI = Talk x V(HCl)(open) / 
V(HCl)(closed)).  The density of seawater at the temperature of the 
measurement (25°C) was calculated from the international equation of state of 
seawater (Millero and Poisson, 1981).  The nominal volume of all cells is 
approximately 200 mL.  If the cells were modified during the cruise, 
adjustments were made to the volumes using the daily titrations on low 
nutrient surface seawater and CRMs.

VOLUME OF TITRANT

The volume of HC1 delivered to the cell is traditionally assumed to have 
small uncertainties (Dickson, 1981) and equated to the digital output of the 
titrator.  Calibrations of the burettes of the Dosimats were done with 
Milli-Q™ water at 25°C.  Since the titration systems are calibrated using 
standard solutions, this error in the accuracy of volume delivery will be 
partially canceled and included in the value of cell volumes assigned.

EVALUATION OF THE CARBONATE PARAMETERS

The total alkalinity of seawater was evaluated from the proton balance at the 
alkalinity equivalence point, pH(equiv) = 4.5, according to the exact 
definition of total alkalinity (Dickson, 1981)

            TAlk = [HCO(3)^-] + 2[CO(3)^(2-)] + [B(OH)(4)^-] + [0H^-]
                 + [HP0(4)^(2-)] + 2[PO(4)^(3-)] + [SiO(OH)(3)^-1]        (9)
                 + [HS^-] + [NH(3)] - [HSO(4)] - [H(3)PO(4)] 

At any point of the titration, the total alkalinity of seawater can be 
calculated from the equation

       (V(0) x Talk - V x N)/(V(0) + Y) 
                    = [HCO(3)^-] + 2[CO(3)^(2-)] + [B(OH)(4)^-] 
                    + [OH^-] + [HPO(4)^(2-)] + 2[P0(4)^(3-)]             (10)
                    + [Si0(OH)(3)^-] + [HS^-] + [NH(3)] 
                    - [H^+] - [HS0(4)^-] - [HF] - [H(3)PO(4)] 

where V(0) is the initial volume of the cell or the sample to be titrated, N 
is the normality of acid titrant, and V is the volume of acid added.  In the 
calculation all the volumes are converted to mass using the known densities 
of the solutions.

A FORTRAN computer program has been developed to calculate the carbonate 
parameters (pHs, E*, TAlk, TCO2, and Pk(4)) in Na(2)CO(3), TRIS, and seawater 
solutions.  The program is patterned after those developed by Dickson (1981), 
Johansson and Wedborg (1982) and Dickson (DOE, 1991).  The fitting is 
performed using the STEPIT routine (J.P. Chandler, Oklahoma State University, 
Stillwater, OK 74074).  The STEPIT software package minimizes the sum of 
squares of residuals by adjusting the parameters E*, TAlk, TCO2 and Pk(1).  
The computer program is based on equation (10) and assumes that nutrients 
such as phosphate, silicate and ammonia are negligible.  This assumption is 
valid only for surface waters.  Neglecting the concentration of nutrients in 
the seawater sample does not affect the accuracy of TAlk, but does affect the 
carbonate alkalinity.

The pH and pK of the acids used in the program are on the seawater scale, 
[H+](SW) = [H+] + [HS0(4)^-] + [HF] (Dickson, 1984).  The dissociation 
constants used in the program were taken from Dickson and Millero (1987) for 
carbonic acid, from Dickson (1990a) for boric acid, from Dickson and Riley 
(1979) for HF, from Dickson (1990b) for HS0(4)^- and from Millero (1995) for 
water.  The program requires as input the concentration of acid, volume of 
the cell, salinity, temperature, measured emf (E), and volume of HCl WHO.  To 
obtain a reliable TAlk from a full titration at least 25 data points are 
collected (9 data points between pH=3.0 to 4.5).  The precision of the fit is 
less than 0.4 μmol/kg when pK(1) is allowed to vary and 1.5 μmol/kg when 
pK(1) is fixed.  Our titration program has been compared to the titration 
programs used by others (Johansson and Wedborg, 1982; Bradshaw et al.,1981; 
Bradshaw and Brewer, 1988) and the values of TAlk agree to within ±1 μmol/kg.  
The performance of our three titration systems has been monitored by 
titrating CRM Batch #16 that have a known TCO2 and constant TAlk.  The 
precision of the values of TAlk on these CRMs was ±2 μmol/kg throughout this 
cruise.  All measured values of TAlk were normalized to the CRM value (2303 
μmol/kg) obtained in the laboratory.



2.3 UNDERWAY MEASUREMENT METHODS

2.3.1 Underway fCO2 Measurements

Underway fCO2 measurements were performed quasi-continuously whenever the 
MALCOLM BALDRIGE was out at sea, and out of territorial waters if no science 
clearance was obtained.  The survey department of the BALDRIGE maintained the 
instrument during the cruise.  The data shown here include the transects from 
Miami to Fortaleza (Leg 0) and from Iceland to Miami (Leg 3).

SYSTEM DESCRIPTION AND PROCEDURES

The underway system used during the cruise is described in detail in 
Wanninkhof and Thoning, (1993).  The shipboard automated underway fCO2 system 
runs on an hourly cycle during which three gas standards, a headspace sample 
from the equilibrator, and an ambient air sample are analyzed using a 
LI-COR™ infrared analyzer.

The IR analyzer/detector's voltage output is measured once per second with a 
Keithley™ (model 195 A) digital multimeter, 1-minute averages are 
calculated and stored on the hard disk of an MS-DOS™ computer.  The mass 
flow controllers (MFCs) connected to the reference and sample inlet of the 
IR, the mass flow meter's (MFM's) measurement of the intake rate of ambient 
air and recirculation rate of the headspace of the equilibrator, the back 
pressure in the air and equilibrated air lines, and two thermistors readings 
of the water temperature in the equilibrator are all logged at 1-minute 
intervals as well.

Compressed gas standards with nominal mixing ratios of 300, 350, and 400 ppm 
flow through the IR analyzer for 5 minutes each hour at 75 mL/min for 
calibration.  The 300 ppm standard flows continuously at 50 mL/min through 
the reference side of the IR analyzer (detector) as well.  All reference 
tanks undergo a pre- and post-cruise calibration at NOAA's Climate Monitoring 
and Diagnostics Laboratory (CMDL) against standards certified by the World 
Meteorological Organization (WMO).

The equilibrator, which was designed by R. Weiss of SIO, is made from a large 
(58 cm H x 23 cm ID) Plexiglas™ chamber.  The equilibrator has a shower 
head in the top through which surface seawater is forced at a rate of 15-20 
L/min.  The water spray through the 16 L head space and the turbulence 
created by the jets impinging on the surface of 8 L of water, cause the gases 
in water and headspace to equilibrate.  A drain 20 cm from the bottom of the 
equilibrator discharges excess water from the system over the side of the 
ship.  Air in the equilibrator head space is circulated with an AIR 
CADET™ pump (model 7530-40) at 6 L/min in a closed loop through a MFM and 
back pressure regulator.  During 23 minutes of each hour, 75 mL/min is teed 
off upstream of the back pressure regulator through a MFC and into the 12 mL 
sample cell of a LICOR™ (model 6251) non-dispersive infrared (IR) 
analyzer.  The air removed from the equilibrator through the IR analyzer is 
replaced with ambient air through an intake/vent line that runs to the 
outside of the ship.  The introduction of the ambient air into the 
equilibrator chamber during sampling of the headspace results in an error in 
the determination of the equilibrated head space composition which is a 
function of water flow rate.  Tests performed during the cruise showed that 
an appreciable bias (~ 1 μatm towards ambient air values) could be introduced 
when water now rates were greater than 20 L/min.  The headspace equilibration 
time, as determined by return to equilibrium after perturbation by adding 
nitrogen to the head space, is approximately 2.5 minutes.  The vent line on 
the equilibrator is necessary to assure that the pressure in the head space 
of the equilibrator remains at atmospheric value.

During underway sampling operations ambient air is drawn through 100 m of 
0.37 cm OD Dekoron™ tubing from the bow mast of the ship at a rate of 6 
to 8 L/min.  During 22 minutes of each hour, ambient air mixing ratios are 
measured in the IR analyzer by teeing off the air line at a flow rate of 75 
mL/min.

UNDERWAY ƒCO2 CALCULATIONS

The mixing ratios of ambient air and equilibrated headspace air are 
calculated by fitting a second-order polynomial fit through the response of 
the detector versus mixing ratio of the standards.  Due to the need for 
sufficient time to flush the sample cell and lines leading to the IR from the 
previous gas, the first three minutes of each analysis run are not used in 
the calculations.  The subsequent one-minute readings for each analysis are 
averaged, yielding one 19-minute average ambient air mixing ratio and one 20-
minute average equilibrated headspace mixing ratio per hour.  Typical 
standard deviations for air values are ±0.1 ppm and ±0.3 ppm for equilibrated 
headspace.

Mixing ratios of dried equilibrated headspace and air must be converted to 
Fugacity of CO2 in water and water saturated air in order to determine the 
driving force for the air-sea CO2 flux.  For ambient air, assuming 100% water 
vapor content, the conversion is:

           ƒCO(2a) = XCO(2a) (P - pH20) exp(B(11) + 2δ(12)) P/RT(SW)     (11)

where pH20 is the water vapor pressure at the sea surface temperature 
(T(SW)), P is the atmospheric pressure, R is the ideal gas constant and T(SW) 
is the sea surface temp (in K) as measured at the bow intake with a 
thermosalinograph.  The exponential term is the fugacity correction where 
B(11) is the second virial coefficient of pure CO2 (B(11) = -1636.75 + 
12.0408T - 0.0327957 T^2 + 3.16528 x 10^-5 T^3) and δ(12) (= 57.7 - 0.118 T) 
is the correction for an air-CO2 mixture (Weiss, 1974).

The calculation for the fugacity in water includes an empirical temperature 
correction term for the increase of WO, due to heating of the water from 
passing through the pump and through 5 cm. ID PVC tubing within the ship.  
The water in the equilibrator is typically 0.2°C warmer than intake 
temperature.  First the fugacity of the air in equilibrium in the headspace 
(W02eq) is calculated according to:

        ƒCO(2eq) = XCO(2eq)(P - pH20(eq))exp(B(11) + 2σ(l2)) P/RT(eq)    (12)

where pH2O(eq) is the water vapor pressure at the temperature of the water in 
the equilibrator and T(eq) is the temperature of the water in the 
equilibrator (in °K).  The CO(2eq) is converted to the fugacity in surface 
seawater ƒCO(2w) by applying an empirical correction suggested by Weiss et 
al., (1982):

  Δln(ƒCO2)/ Δt(SW) = 0.03107 - 2.785 10^(-4t) - 1.839 10^(-3) ln(ƒCO2) (13)

where t is the SST in °C.

COMMENTS ON DATA

The cruise track is shown in Figure 1 and the data are presented in graphical 
format for each segment in Figures 21 to 25.  The data are plotted either 
versus latitude or longitude depending if the track trended north-south or 
east-west. Figures 21 though 24 have a top panel with ƒCO(2W) (filled circles 
with dashed line) and ƒCO(2a) (empty circles) and a bottom panel with a 
double Y graph depicting SST (empty circles), and salinity (filled circles 
dashed line) as determined from the thermosalinograph at the bow intake. The 
figures show the large scale features along the track.  Between Miami and 
Fortaleza the waters are on average supersaturated by approximately 20 μatm, 
except in the region with very low salinity (caused by Amazon River outflow) 
near 10°N and 55°W which is undersaturated (Figure 21).  The irregularities 
between 50°W and 40°W are caused by the ship steaming in a grid pattern in a 
region with significant gradients.  Figure 22 is the transect from 5°S to 
Iceland.  The ocean is supersaturated up to 40°N at which point the N.  
Atlantic turns into a strong sink.  The low salinity region at 8°N, caused by 
excess precipitation and perhaps river outflow, is a CO2 sink as well.  The 
transect from Iceland to Miami shows undersaturation from Iceland to 50°E, 
the region from 50°E to 40°E is close to saturation while the region further 
to the southwest is a source for CO2.

During the cruise segment from Fortaleza to 3°N, 25°W the air analyses 
drifted significantly during the 20-minute sampling period and were above the 
expected seasonal values for the region.  This behavior was also observed for 
several other cruises with this system.  Replacement and/or cleaning of 
nearly all the components in the air line (tubing to the bow, mass flow 
meters, and solenoids) eliminated the problem.  We hypothesize that sea salt 
aerosols coated the air intake lines and that CO2 was gradually released from 
the carbonate and bicarbonate salts due to heating of the lines and acidic 
air.  The air mixing ratios for the region were extrapolated based on values 
before and after the problem arose.  Stations of the NOAA/CMDL flask network 
(Ascension Island, and Key Biscayne, FL) were too far removed to improve the 
extrapolation.

The thermistors in the equilibrator were calibrated before the cruise and 
compared to 6-hourly readings of a mercury thermometer in the equilibrator 
throughout the cruise.  Based on the pre-cruise calibrations the resistances 
of the thermistor were converted to temperatures using a second order 
polynomial fit.  The agreement with the shipboard thermometer readings was 
reasonable (Figure 25) except for SST < 12°C because the laboratory 
calibration was only performed down to 12°C.  A secondary correction was 
applied to the thermistor based on the comparison between the Teqand the 6-
hour thermometer readings.  A fifth-order least squares best fit polynomial 
was applied to the difference in T(eq) and T(thermometerversus) T(eq) (Figure 
25).  This correction was subsequently applied to the T(eq) values used to 
calculate the ƒCO(2eq).

The air XCO2 values were compared at 6 locations with duplicate flask samples 
obtained from the bow of the ship during the cruise and analyzed at CMDL.  
Table 4 shows that the results agree to better than 1 ppm, suggesting good 
accuracy of the calibrated infrared analyzer used during the cruise.


TABLE 8. Dependence of headspace mixing ratio on water flow rate through 
         equilibrator (from Chen, et al. 1995).
             ______________________________________________________
             
              FLOW  MIXING RATIO(a)  EQUIL.  CORR.X(b)  %EQUIL.(c)
              ----  ---------------  ------  ---------  ----------
               20    389.57 ±0.06    24.05    389.57      96.7
               15    390.72 ±0.25    24.05    390.72      99.6
               10    391.54 ±0.35    24.09    390.87 
               15    389.75 ±0.12    24.04    389.91      97.6
               20    388.28          24.00    389.10      95.6
             ______________________________________________________
             Comments:
              a: The air mixing ratio during the test was 351.0 ± 0.2 ppm.
              b: Corr. X is the ratio normalized to 24.05°C using 
                 δX(CO2)/δT=0.0423.
              c: percent equilibration is defined as:
                 (X(CO2)water-air)@xL/min/(X(CO2)water-air)@10L/min * 100


TABLE 9. Comparison of in situ air values vs. flask samples analyzed at CMDL
         _______________________________________________________________
         
           J.D.    Lat    Long   AIR CO2  s.d.  CMDL 1     2      diff.
          ------  -----  ------  -------  ----  ------  --------  -----
          190.83  -1.29  -25.02  356.99   0.12  357.2    356.98   -0.1
          198.08  13.4   -28.89  355.93   0.19  355.94   356.85   -0.47
          202.83  22.8   -22.53   53.78   0.07  354.1    354.05   -0.3
          217.63  26.64  -25.41  355.39   0.09  355.76             0.37
          221.92  15.91  -29     353.61   0.1   353.88   353.83   -0.25
          225.83  28.57  -24.36  353.54   0.07  353.83   54.06    -0.39
          240.54  61.84  -19.75  348.39   0.09  347.57   347.46    0.88
                                                        --------  -----
                                                        Average   -0.14
                                                        St. Dev.   0.46
         _______________________________________________________________
         Comments:
          J.D.     = fractional Julian day (GMT)
          Lat      = Latitude (fractional degrees)
          Long     = Longitude (fractional degrees)
          Air CO2  = air mixing ratio obtained ship board
          s.d.     = standard deviation of 19 consecutive 1-minute averages
          CMDL I   = results of analysis of flask #1 performed at NOAA/CMDL
          2        = results of analysis of flask #2 performed at NOAA/CMDL
          diff.    = difference between air CO2 value and average of the two    
                     CMDL analyses



3. ACKNOWLEDGMENTS

The dedication and assistance of the officers and crew of the NOAA ship 
MALCOLM BALDRIGE is gratefully appreciated and hereby acknowledged.  In 
particular, we would like to thank the Survey Department under the direction 
of Chief Survey Tech Dennis Sweeney for their capable assistance with the CTD 
and underway systems.



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APPENDIX A: Contour Plots (See PDF file)

This appendix contains contour plots of all hydrographic and chemical 
parameters, plots of underway measurements (see Section 2.3 for explanation), 
and plots comparing AOML and U.W. nutrient values.  Figures 2 through 20 
were generated using Surfer™ for Windows™ version 6.04.  Only values 
with a qc flag value of 2 (good) were used in gridding the data.  Gridding 
was accomplished using the built in Kriging algorithm with an anisotropy of 
four and no smoothing.  The 0-6000 db plots were created from 140 column by 
81 row grids and the 0-1000 db plots were created from 140 column by 34 row 
grids.  Hachures in enclosed contours mark relative minima in the plot.  Each 
contour plot includes a scale bar showing the contour levels used.

Nutrient plots (Figures 9 through 14) were done in two ways for each 
individual nutrient.  Plots labelled "U.W. & AOML" use University of 
Washington nutrient values for Leg 1 (to about 15°N) and AOML values for all 
other stations.  The plots labelled "AOML" use AOML nutrients for all 
stations.  Figures 26 through 28 show a comparison of AOML and U.W. nutrients 
with the difference (U.W. value - AOML value) on the Y-axis and the U.W. 
value on the X-axis.



DATA PROCESSING NOTES


DATE        CONTACT     DATA TYPE      EVENT SUMMARY
----------  ----------  -------------  ------------------------------------------
1999-10-01  Bartolacci  CTD/BTL/SUM    sent to S.Anderson for reformatting

2000-01-11  Wanninkhof  CTD            Submitted  needs reformatting

2000-05-06  Wanninkhof  CTD            Data are Public  
            I did not realize that the data were in non-public status. Feel 
            free to release it to the community at large (recognizing that not 
            all data meets WOCE specifications).  Don't hesitate to contact us 
            if there are further questions.

2000-06-12  Bartolacci  CTD            Website Updated:  data are public

2000-07-24  Huynh       Cruise Report  Website Updated:  txt version online

2001-02-12  Muus        CTD            Update Needed  
            Notes   Feb 12, 2001    D. Muus
            AR21   EXPOCODE 
            Data to be reformatted taken from:
            /usr/export/html-public/data/repeat/atlantic/ar21/ar21_b/original/

            ar21.csv        ar21.des        ar21_93_ctd.zip
            CTD file taken from web Feb 2, 2001:   ar21_bct.zip  dated 000612
             diff indicates ar21_bct.zip same as ar21_93_ctd.zip
              No quality codes in CTD files.
              No bottom depths.
              CTD Cast numbers consecutive through cruise, not by station.
              Used CTD cast numbers in file names. Station numbers are in 
                comments.
              No Bottle Number from originator but Bottle quality code is 
                included.
              Sample Number appears to be Rosette Cast # and Bottle #.
              Rosette Cast Numbers are different sequence from CTD cast numbers 
                and are also consecutive for the cruise not just each station. 
              Missing rosette cast number probably other event not connected to 
                Rosette and CTD work.
              TCARBN was listed in original data as TCO2. 
              PCO2 is PCO2 at 20 deg C.
              In-situ PCO2 is in original data file but not in exchange file. Can
                 be calculated from data available in exchange file.
              PH is spectrophotometric pH at 20 deg C

2001-02-25  Bartolacci  CTD/BTL        Website Updated: btl encrypted, ctd public
            2001.02.25  DMB

            Reformatted exchange bottle and zipped ctd files were copied from 
            Dave Muus' directory to this subdirectory and put online.  No WOCE 
            formatted files exist to date.

            The CTD and BOTTLE exchange files should be read into OceanAtlas as 
            a check before making them available to anyone outside WHPO.

            They are now in ~dave/DANIE/AR21b/ar21_b_ct1.zip/ar21_b_hy1.csv
                   D. Muus   Feb 12, 2001
            Feb 14, 2001, successfully read into OceanAtlas by Jim Swift.  dm




DATE        CONTACT     DATA TYPE      EVENT SUMMARY
----------  ----------  -------------  ------------------------------------------
2002-05-01  Bartolacci  CTD/BTL        Update Needed  Exchange BOT & CTD online 
            need WOCE fmttd files. BOT CTD NONPUB. Create WOCE fmttd files. 
            Create SUM. Email Wanninkhov for PUB status.

2005-01-04  Key         BTL            Data are Public
            The data for this cruise have been public for quite some time so it 
            may be worthwhile to check that the version you have is current. 
            The NOAA people routinely refer to this cruise as OACES93 or A16N 
            with the EXPOCODE you have in the table. This is one of their 
            repeat sections, but the timing of the repeat is further apart than 
            a typical WOCE repeat cruise.


2005-01-05  Key         Cruise Report  Submitted  scanned, pdf doc

2005-01-05  Key         DELC13/DELC14  Submitted  Updated data files
            With this message I've attached myAR21b (1993 Baldrige occupation 
            of A16N) files even though you didn't ask. I'm certain that my file 
            is the only copy anywhere that has C14 data and may be the only one 
            with QCed C13. I've also attached my README file for this cruise. 
            The files currently at AOML and CDIAC were built from my reworking 
            of their original files as part of GLODAP so I can answer any 
            questions that arise. The only thing that will need to be fixed to 
            create formal exchange format are:column labels, column order  and 
            number of decimal places (my code drops trailing decimal 0s and/or 
            prints too many decimal places. I included calculated values 
            (depth, theta, aou, sigmax), which you may want to drop and 
            recalculate in case of minor function differences.

            Other than the information that is included in my README, you 
            already have posted all the metadata I know about other than a 
            final report (also attached) which I found on the AOML CO2 web site 
            as a pdf file.

2005-04-13  Key         OXY/PHS/SIL    Update Needed: Add 7.5 µmol/kg to oxy values
            On 1/5/05 I submitted to you a copy of the data from the 1993 NOAA 
            occupation of A16N (Malcolm Baldridge, NOAA called it OACES93). I 
            mentioned that the carbon community used this cruise rather than 
            32OC202_1,2 as the WOCE era occupation of this line (the Oceanus 
            cruise did not have carbon measurements). 

            In the final data report for that cruise the participants suggested 
            that 7.5 µmol/kg should be added to the oxygen values.  The version 
            of the data i sent you included that oxygen adjustment.

            The need for an adjustment to the oxygen data was confirmed by V. 
            Gouretski's objective analysis of Atlantic data. He derived an 
            adjustment of 5.05 µmol/kg (.116ml/l) for stations 32-83 (no 
            adjustment for stations 1-31). Gouretski also estimated that the 
            phosphate and silicate values needed minor adjustment. None of the 
            Gouretski adjustments were in what I sent.

            I don't know the WHPO policy for such situations. It is easy enough 
            to back out the adjustment I made if required. Regardless, a 
            footnote to the oxygen data for this cruise is required (or at 
            least desirable). This cruise has not yet appeared on your Atlantic 
            web page. The CDIAC and NOAA versions of this data do NOT have the 
            oxygen correction applied.




DATE        CONTACT     DATA TYPE      EVENT SUMMARY
----------  ----------  -------------  ------------------------------------------
2005-04-13  Key         Cruise ID      Believes this should be A16N
            On 1/5/05 I submitted to you a copy of the data from the 1993 NOAA 
            occupation of A16N (Malcolm Baldridge, NOAA called it OACES93). I 
            mentioned that the carbon community used this cruise rather than 
            32OC202_1,2 as the WOCE era occupation of this line (the Oceanus 
            cruise did not have carbon measurements). 

            In the final data report for that cruise the participants suggested 
            that 7.5umol/kg should be added to the oxygen values.
            The version of the data i sent you included that oxygen adjustment.

            The need for an adjustment to the oxygen data was confirmed by V. 
            Gouretski's objective analysis of Atlantic data. He derived an 
            adjustment of 5.05 umol/kg (.116ml/l) for stations 32-83 (no 
            adjustment for stations 1-31). Gouretski also estimated that the 
            phosphate and silicate values needed minor adjustment. None of the 
            Gouretski adjustments were in what I sent.

            I don't know the WHPO policy for such situations. It is easy enough 
            to back out the adjustment I made if required. Regardless, a 
            footnote to the oxygen data for this cruise is required (or at 
            least desirable). This cruise has not yet appeared on your Atlantic 
            web page. The CDIAC and NOAA versions of this data do NOT have the 
            oxygen correction applied.


2005-04-19  Key         Cruise ID      Recommends Line # change to A16N
            Based on the WHPO repeat cruise table, this does appear to be the 
            same cruise. The data for this cruise have been public for quite 
            some time so it may be worthwhile to check that the version you 
            have is current. The NOAA people routinely refer to this cruise as 
            OACES93 or A16N with the EXPOCODE you have in the table. This is 
            one of their repeat sections, but the timing of the repeat is 
            further apart than a typical WOCE repeat cruise. Presumably that is 
            the the reason I didn't even check this area of your site.

            On the same page you have listed the 1991 M. Baldrige cruise. Under 
            the data link there is no bottle data. These data are public and i 
            have a copy of everything with WOCE flags added. I can provide a 
            copy if you need it or alternately, it should be available from 
            Kozyr at  CDIAC.

2005-04-19  Key         Cruise ID      Cruise ID confusion May be A16N
            Under Atlantic One-Time cruises WHPO lists the 2003 Ron Brown 
            cruise, but not the 1993 NOAA occupation of this line. Carbon 
            people generally use the 1993 NOAA cruise for the WOCE occupation 
            of this line rather than the 1988 Oceanus cruise (which does not 
            have carbon data). I  believe that the 1993 NOAA cruise data should 
            be added to WHPO since the CLIVAR focus is more carbon oriented 
            than WOCE and change is paramount. Fortunately, this is easy since 
            Kozry has the data and cruise report online:

            See item number 9 at http://cdiac.esd.ornl.gov/oceans/other.html

            For what it's worth, GLODAP used the 1993 NOAA cruise as the 
            official WOCE occupation of A16N. In our final data set we applied 
            the salinity, oxygen and nutrient corrections derived by V. 
            Gouretski. There were no corrections necessary for any of the 
            carbon parameters.

            If you have any trouble at all with Alex's version of the data 
            file, I can provide one in the normal format I send.



DATE        CONTACT     DATA TYPE      EVENT SUMMARY
----------  ----------  -------------  ------------------------------------------
2005-04-20  Swift       CDOM           Submitted  Data are Final

2005-12-15  Johnson     CTD/BTL        Data are Public  aka: A16N_1993
            I have indeed published a paper on LSW differences along A16N 
            including oxygen analyses in GRL (Johnson et al. 2005) this year 
            using A16N data.

            The manuscript on SPMW oxygen differences is not yet out but it 
            will be published (someday) in Prog. Oceanogr. in a special issue.  
            That manuscript (Johnson & Gruber) has been accepted by the special 
            issue guest editor (I. Yashayaev) and forwarded to one of the two 
            editors-in-chief (D. Quadfasel), but I am not sure just how far 
            along the whole issue is at present.

            You can find the 1998 data at the CCHDO under the repeat data 
            (AR21):

            http://whpo.ucsd.edu/data/tables/repeat/subs/ar21_table.htm

            which is where I got them.  The 1993 data are also listed in that 
            table as residing at the WHPO, but the bottle data are still not 
            public.  However, you can find them at this web site

            http://www.aoml.noaa.gov/ocd/oaces/natl93.html

2008-06-22  Kappa       Cruise Report  New pdf & text docs compiled
            Reformatted NOAA Data Report ERL AOML-32 as pdf and text documents 
            to replace the prelilminary text report currently online for this 
            cruise.  Added data processing notes, new station track, and made 
            text in pdf searchable.





