A.	CRUISE NARRATIVE:  A11

A.1.	HIGHLIGHTS

                         WHP CRUISE SUMMARY INFORMATION
         WOCE section designation  A11
Expedition designation (EXPOCODE)  74DI199_1
      Chief Scientist/affiliation  Peter Saunders, IOSDL*
                            Dates  1992.12.22 - 1993.02.01
                             Ship  R/V DISCOVERY
                    Ports of call  Punta Arenas, Chile to 
                                   Cape Town, South Africa
               Number of stations  91
                                                30°13.50'S
    Station Geographic boundaries  00°09.35'W                17°50.72'E
                                            45°04.62'S
     Floats and drifters deployed  none
   Moorings deployed or recovered  none
                              Contributing Authors
B.A. King         S. Bacon         P. Chapman     S.E. Holley    D.J. Hydes
D. Smythe-Wright  S.M. Boswell     D. Price       S. Jordan      R. Phipps
S. Whittle        T.J.P. Gwilliam  S.R. Thompson  R. Marsh       M.G. Beney
A.J. Taylor       K.J. Heywood     P.K. Smith     S. Cunningham  M.P. Meredith
V.C. Cornell


                             CRUISE REPORT NO. 234
                             Version 2   June 1994
             *Institute of Oceanographic Sciences Deacon Laboratory
               Brook Road, Wormley, Godalming, Surrey, GU8 5UB, UK.



ABSTRACT

RRS Discovery cruise 199 was a UK contribution to the World Ocean 
Circulation Experiment (WOCE) one-time survey, its designation A11.  The 
cruise ports were Punta Arenas, Chile to Cape Town, S. Africa.  91 full-
depth stations were worked with a NBIS Mk3b CTD and a GO 24x10 liter 
rosette water sampler.  Salinity, oxygen, silicate, nitrate, phosphate 
were measured on each station, CFC-11, CFC-12, and CFC-113 measured on 
every other station and XBT drops (mostly T7) made between stations.  
Meteorological parameters, sea-surface temperature and salinity, and 
current profiles to 300m (from a hull-mounted RDI 150 kHz ADCP) were 
measured throughout the cruise.  To improve estimates of the ship's 
heading (and hence currents) a 3-dimensional gps receiver from Ashtech 
was employed.

Provisional examination of the data indicates that it is of sufficient 
quality to meet the principal aim of the cruise, namely to determine the 
exchange of physical and chemical properties between the S. Atlantic and 
Southern Ocean.

Electronic versions of the text of this document, plus hard copy figures 
are lodged with the WOCE Hydrographic Planning Office, Woods Hole, Mass 
and with the British Oceanographic Data Centre at Bidston, Merseyside.

KEYWORDS

ACOUSTIC DOPPLER CURRENT PROFILER (ADCP)
A11 WOCE ONE-TIME SURVEY
CFC 11,12,113
CORE PROJECT 1
CTD OBSERVATIONS
"DISCOVERY"/RRS - CRUISE (1992-3) 199
NUTRIENTS
OXYGEN
WOCE


WHP CRUISE AND DATA INFORMATION 

CONTENTS

1	CRUISE NARRATIVE
1.1	Highlights
1.2	Cruise Summary
1.3	List of Principle Investigators
1.4.1	Scientific Programme and Methods
1.4.2	Preliminary Results
1.5	Major Problems Encountered on the Cruise
1.6	Other Observations of Note
1.7	List of Cruise Participants

2	MEASUREMENT TECHNIQUES AND CALIBRATIONS
	A general note on data quality checking
2.1	Sample salinity measurements
2.2	Sample oxygen measurements
2.3	Nutrients
2.4	CFC-11, CFC-12, and CFC-113
2.5	Samples taken for other chemical measurements
	a) Oxygen and Hydrogen isotope ratios
	b) Iodine
2.6	CTD Measurements
	a) Gantry and Winch Arrangements
	b) Equipment, calibrations and standards
	c) CTD Data Collection and Processing
2.7	XBTs
2.8	Acoustic Doppler Current Profiler (ADCP)
2.9	Navigation
	a) GPS-Trimble
	b) Electromagnetic log and gyrocompass
	c) Ashtech GPS3DF Instrument
2.10	Underway Observations
	a) Echosounding
	b) Meteorological Measurements
	c) Thermosalinograph measurements
	d) Satellite Image Acquisition and Processing
2.11	Shipboard computing
2.12	Cruise diary
	COMMENCEMENT OF THE A11 SECTION (45°S, 60°W)
	THE TURNING POINT ON THE A11 SECTION (45°S, 15°W).
	END OF A11 SECTION

ACKNOWLEDGEMENTS
CTD STATION LIST
XBT STATION LIST
FIGURE LEGENDS
FIGURES 1-20

DQE REPORTS
	CTD
	Nutrients

DATA STATUS NOTES


1.   CRUISE NARRATIVE 
1.1  HIGHLIGHTS
Expedition Designation:	WHP One-time Survey, A11
Chief Scientist:	Peter M Saunders, IOSDL
Ship:			RRS Discovery, newly lengthened to 90.2m
Ports of Call:		Punta Arenas, Chile to Cape Town, S. Africa
Cruise Dates:		December 22, 1992 to February 1, 1993

1.2  CRUISE SUMMARY

CRUISE Track
The cruise track and station locations are shown in Figure 1: only small 
volume samples were taken.

SAMPLING
following water sample measurements were made:- salinity, oxygen, 
total nitrate, phosphate, silicate and CFCs 11,12 and 113, the freons on 
alternate stations.  CTD salinity and oxygen were also measured.

The depths in m sampled were:- 5(10), 50, 100, 150, 200, 250, 350, 500, 
750, 1000, 1250, 1500, 1750, 2000, 2500, 3000, 3500, 4000, 4500, 5000, 
5500, 6000 meters.

NUMBER OF STATIONS
A total of 91 CTD/rosette stations were occupied using a General 
Oceanics 24 bottle rosette equipped with 24 10-litre Niskin water sample 
bottles, and a NBIS Mk IIIb CTD equipped with a SensorMedic oxygen 
sensor, Sea Tech Inc 1 m path transmissometer, Simrad altimeter model 
807-200m, and IOSDL 10 kHz pinger.

FLOATS, DRIFTERS, AND MOORINGS
No floats, drifters, or moorings were deployed on this cruise.

REPORTING
Electronic versions of the text of this document, plus hard copy figures 
are lodged with the WOCE Hydrographic planning office, Woods Hole, Mass 
and with the British Oceanographic Data Centre at Bidston, Merseyside.  
We plan to lodge electronic copies of most of the data from the cruise 
at these same sites by the end of 1993.


1.3  LIST OF PRINCIPLE INVESTIGATORS

The principal investigators responsible for the major parameters 
measured on the cruise are listed in Table 1.  The responsibility for 
all tasks undertaken on the cruise will be found in table 2.


TABLE 1: PRINCIPAL INVESTIGATORS

NAME		 RESPONSIBILITY		AFFILIATION
B. King		 CTD			IOSDL
S. Bacon	 Salinity		JRC
D. Hydes	 Nutrients		IOSDL
P. Chapman	 Oxygen			Texas A & M
D. Smythe-Wright CFC			JRC
P. Saunders	 ADCP			IOSDL
P. Smith	 Meteorology		IOSDL
S. Thompson	 XBTs			IOSDL
M. Meredith	 Satellite imagery	UEA
		 (MACSAT) and thermosalinograph


1.4.1  SCIENTIFIC PROGRAMME AND METHODS

The principal objectives of the cruise were:

a) To estimate the exchange of heat, freshwater, nutrients and freons 
   across the section, i.e. between the Southern Ocean and the South 
   Atlantic
b) To determine the water mass characteristics on the section and to 
   determine whether and where secular changes are found, and
c) To submit to the WHPO a data set, a fit companion to other WHP one 
   time survey cruises, and thereby contribute to the global 
   measurements necessary to meet the objectives of WOCE.

The principal instruments employed in the measurement programme 
consisted of a NBIS Mk IIIa CTD and General Oceanics rosette mounted 
within a tubular aluminum frame of dimensions 1.8m height x 1.5m 
diameter.  The package was weighted to give a free fall speed in excess 
of 2 ms-1.  Subsidiary instrumentation consisted of a 1m 
transmissometer, altimeter (with 200m range for bottom finding) and 10 
kHz location pinger.  Four of the rosette bottles were fitted with SIS 
digital reversing thermometers (6) and pressure meters (2).  The wire 
was a single conductor 10mm steel rope manufactured by Rochester Cables, 
and the winch was of traction winch design built by Kley France.  A 
complex folding gantry of RVS Barry design ensured the virtually 
automatic launching and recovery of the CTD/rosette package in all 
conditions within which the ship could be safely operated.

After a cast the rosette was placed on deck and secured, the rosette 
pylon was drenched in fresh water and the CTD sensors covered with 
protective housings.  Subsequently digital instrumentation was read and 
freon samples were drawn followed in order by samples for oxygen, 
nutrient and salinity analysis.  The rosette was stored on deck 
throughout the cruise and all sampling was performed there.  In moderate 
weather the rosette would be pushed forward on a railway about 3 m to 
obtain further shelter.  In rain umbrellas could be clamped to the 
rosette frame in order to protect the samples and in rough seas the ship 
remained on station until sampling was completed.

Other and, in some cases, crucial additional measurements were made 
throughout the cruise.  XBTs were launched between CTD stations and more 
frequently in the slope regions at each end of the cruise section.  
Acoustic Doppler Current Profiler (ADCP) measurements were made 
continuously employing a hull mounted 150 kHz unit manufactured by RDI.  
In support of the ADCP measurements a GPS3DF receiver manufactured by 
Ashtech, Inc provided heading information superior to that of the ship's 
gyro.  Underway measurements of surface temperature and salinity were 
made by a FSI thermosalinograph and a Simrad 500 Echosounder provided 
continuous water depth measurements.  Other navigation information was 
supplied by a Trimble GPS receiver and all data were logged by networked 
SUN workstations with terminals widely available in the main and 
computer labs.

A description of the methods of measurement, calibration and analysis of 
the data received from these various sources will be found in section 2 
of this report.


1.4.2  PRELIMINARY RESULTS

Figure 2 shows the distribution of sample observations made on the A11 
section.  Since data from the South Atlantic Ventilation Experiment 
(SAVE) were available on the ship (thanks to WHPO), we were able to 
compare A11 and SAVE sample data.  The property distributions were very 
similar, but small differences were noted in the deep water which became 
evident with potential temperature < 1.0°C or salinity in the range 
34.66 - 34.72.  A11 salinity measurements agreed well with the SAVE 5 
leg data, but were more saline by 0.002 than adjacent SAVE 4 data: the 
differences amongst the SAVE data were not previously known to us.  
Nitrates showed agreement with both SAVE 4 and 5 measurements, but at 
the deepest levels silicates and oxygens were slightly lower by 2.5 
µmol/kg (Figure 3) and 2.5 µmol/kg (Figure 4) respectively; phosphates 
were lower by about 0.08 µmol/kg.  These preliminary results, whose 
magnitude but not sign depends on which historic set is compared, apply 
principally within the Argentine Basin, and possible causes of the 
differences are under investigation.

A more unexpected result, which owed nothing to the accuracy of the 
measurements, was the extreme northern position of the Subtropical 
Convergence on the NE leg of the track (Figure 1).  Although the water 
became progressively warmer along this leg, the surface salinity 
remained below 35 until a ring was encountered centered on 36°20'S and 
4°00'E.  The ring had a thermostad of temperature 13.5°C, salinity 35.2 
and a maximum depth of 600m.  An anticyclonic circulation of 30 cms-1 
was observed by the ADCP.  It may have been an Agulhas ring which had 
over-wintered south of the convergence, or a Brazil Current ring shed in 
the WBC retro-flexion zone which had migrated eastward.  Opinions in the 
scientific party were split about equally, but a closer post-cruise 
examination of the data may well resolve the question.  Beyond its NE 
edge, near 35°40'S and 5°00'E we encountered the subtropical gyre, with 
a surface salinity exceeding 36 and temperature of 20°C.  This 
observation appears to confirm Deacon's (1937) assertion of the 
northward migration of the convergence in summer in this region.

Within the subtropical gyre a second hydrographic feature was 
encountered.  This was defined by two hydrographic casts and 5 XBTs and 
was centered at 33°30'S, 9°45'E and extended for 300 km along the track.  
Within it, the 15°C isotherm plunged to a depth of 250m, while outside 
it the same isotherm was nearer a depth of 100m.  An anticyclonic 
circulation was measured by the ADCP with currents approaching 75 cms-1.  
This was undoubtedly a recent Agulhas ring.

The ADCP instrumentation furnished, we believe, important new data on 
the cruise: it functioned incomparably better than when installed on the 
previous 10m-shorter version of the ship.  The most important results 
derived from it were found in the western boundary region.  On the 
Argentine Slope, on two crossings of the Falklands Current, large and 
persistent northward velocities were found at 100m depth (30 - 50 cms-
1).  These were considerably in excess of those predicted by the 
geostrophic shear (relative to the bottom), and consequently bottom 
velocities of 15 - 30 cms-1 are inferred.  The consequences for 
transport in the WBC and exchange across the section are considerable.  
On the South African slope, along-slope velocities were also observed on 
a crossing of the Benguela Current.  However these were quite small and 
variable in direction and a preliminary analysis suggested they were 
dominated by transient (tidal or inertial) components.

Also of note were ADCP observations made in a storm near 45°S 21°W: 
winds approached 30 ms-1 for a brief period, and striking inertial 
oscillations (circa 40 cms-1) were recorded.  Since meteorological 
measurements were made aboard the ship, it is hoped that given the high 
quality of the ADCP data, it may prove possible to deduce the integrated 
Ekman drift on this cruise.


1.5  MAJOR PROBLEMS ENCOUNTERED ON THE CRUISE

Two GO rosettes were available and both were utilized.  Misfiring and 
double tripping were initially widespread, but when their sensitivity to 
the lanyard tension was recognized it became possible to reduce them to 
acceptable levels.  Nevertheless a post-cruise review estimates the 
overall number of double trips as nearly 10% of the total number of 
samples.  Thus a larger than expected number of duplicate samples was 
achieved.  It is our recommendation and intention for the future that 
lanyard tensions be measured, monitored and set to a value which allows 
a properly reliable operation of the unit.

As mentioned in Section 1.4.1 the winch was of complex traction winch 
design; it was put to use only on the previous cruise and because of its 
newness, inevitably there were difficulties.  On the 1st of January at 
0600, control failure occurred: it was approximately 36 hours before the 
fault was identified, the electronic component replaced and control 
settings optimized to allow station work to proceed.  The efforts of all 
involved deserve recognition and thanks.  Although we believe this was a 
unique situation, a different problem occurred twice and was potentially 
liable to occur anytime there was a large swell.  Because the 
CTD/rosette takes time to shed air from all its component parts, very 
close to the surface it is vulnerable to heavy swell: it may 'float'.  
In such circumstances the wire goes slack, and on both occasions the 
wire jumped out of a sheave pair at the foot of the gantry (where the 
wire direction changed from horizontal to vertical).  Even in the short 
term this is probably a rectifiable fault, but on the cruise it cost us 
4 hours both times it occurred.

Concerning the instrumentation for analysis, two problems were noted.  
Early on, the SIS unit for determination of oxygen concentration became 
unreliable: the photometric end point detection system was no longer 
stable.  Fortunately a backup amperometric system, the Metrohm 686 
titroprocessor, was available, and this was used for the bulk of the 
cruise measurements.

The CFC measurements also experienced difficulties which led to the loss 
of some data.  Shortly after the start of the cruise the CFC-12 
measurements exhibited severe contamination which was believed to be due 
to the accidental release of oil from the ship and its capture in the 
non-toxic seawater system used to store the sample syringes.  To bypass 
this problem, syringes were stored in surplus sample water, a practice 
however, which did not eliminate the contamination.  Early CFC-12 
measurements may be expected to be of lower quality than expected on the 
cruise, but the CFC-11 and CFC-113 measurements should be unaffected.


1.6  OTHER OBSERVATIONS OF NOTE

On the 16th January, a large iceberg was sighted: its location was 
determined as 44°50'S 14°22'W.  In view of a much more southerly 
position and crossing of the Falkland Current three weeks earlier in the 
cruise, this was an odd location to observe one for the first time.

On the 19th January in about 3700m of water, RRS Discovery passed over a 
flat-topped seamount near 40°48'S 5°40'W: it is not recorded on the 
GEBCO chart and its minimum depth was near 750m.  We propose the name 
New Discovery Seamount for this 3000 m high feature.


1.7  LIST OF CRUISE PARTICIPANTS

The members of the scientific party are listed in Table 2, along with 
their responsibilities.


TABLE 2:  CRUISE PARTICIPANTS

NAME		 RESPONSIBILITIES		AFFILIATION
____________________________________________________________________
S. Bacon	 Salinity			JRC
M. Beney	 Data acquisition		RVS
S. Boswell	 CFCs				JRC
P. Chapman	 Oxygens, nutrients		Texas A & M
V. Cornell	 Data archiving, Macsat		JRC
N. Crisp	 CTD operations			IOSDL
S. Cunningham	 CTD/sample analysis		JRC
P. Gwilliam	 CTD operations (IC)		IOSDL
V. Gouretski	 ADCP/historical hydrography	UEA
K. Heywood	 CTD/sample analysis		UEA
S. Holley	 Oxygens, nutrients		JRC
D. Hydes	 Nutrients, oxygens		IOSDL
S. Jordan	 Mech.  Eng (IC)		RVS
B. King		 CTD/sample analysis		IOSDL
R. Marsh	 ADCP				JRC
M. Meredith	 Thermosalinograph, Macsat	UEA
D. Price	 CFCs				JRC
R. Phipps	 Mechanical Engineer		RVS
P. Saunders	 PSO, ADCP			IOSDL
P. Smith	 CTD operations, Meteorology	IOSDL
D. Smythe-Wright CFCs (IC)			JRC
A. Taylor	 Electrical Engineer		RVS
S. Thompson	 GPS, XBTs			IOSDL
S. Whittle	 Mechanical Engineer		IOSDL

Abbreviations

IOSDL	Institute of Oceanographic Sciences, Deacon Laboratory - Wormley
JRC	James Rennell Centre - Southampton
RVS	Research Vessel Services - Barry
UEA	University of East Anglia - Norwich
IC	In charge of


2  MEASUREMENT TECHNIQUES AND CALIBRATIONS

A GENERAL NOTE ON DATA QUALITY CHECKING (OCT 93)
(B. A. King)

Note that a number of sections on data quality checking have been added 
to this report (the .DOC file kept by the WHPO) since the submission to 
the WHPO of the initial cruise report in February 1993.  Such additions 
are identified with dates in the subheadings.  The consequence of 
maintaining a single report file is that some figures are introduced out 
of order, and some information may appear more than once in the text.

One problem when looking for small differences between two profiles of 
sample data for example between adjacent stations in a single data set 
or a comparison of data from different cruises, is that the size of any 
difference is likely to be smaller than the variation of the property 
over a few hundred meters in the vertical.  This combines with the fact 
that the samples are not necessarily collected at the same vertical 
coordinate (usually pressure or potential temperature) to create 
something of a difficulty.

However, the following procedure has been found to be a useful way round 
this problem, both for checking the internal consistency of the data set 
and in the comparison with historical data.

  (i) The deep data are plotted in a theta-property plot, and a 
      fraction of the data selected which are closely described by a 
      linear regression of the sample value on potential temperature.  
      This invariably led to different regressions for the western and 
      the eastern basin.  Typically, the western basin regression would 
      be calculated from data with theta < 1.0 degree, and the eastern 
      basin regression from data with theta < 1.2 degrees. 
 (ii) For each sample value, the chosen regression is used to 
      compute a 'predicted' value of the sample, and the anomaly 
      between the observed value and this predicted value is 
      calculated.  If the data are well described by a linear fit with 
      theta, these anomalies should be small, probably an order of 
      magnitude smaller than the variation in the vertical of the 
      fitted data. 
(iii) There are now a number advantages: first, it is now 
      straightforward to compare samples collected at different depths, 
      by comparing their anomalies; second, any offset between profiles 
      of a magnitude greater than the normal scatter in the anomalies 
      is immediately apparent; third, the mean value of the anomalies 
      for a station provides a simple and objective way to summarize 
      the property value for that station in a single number.

The key to this technique is to use the same prediction for every 
station being considered for inter-comparison.  For comparisons between 
cruises it is not particularly important which data set is used to 
determine the fitting equation, so long as it removes the background 
distribution in each data set.  We have used linear fits based on the 
present data.

COMPARISON WITH HISTORICAL DATA (OCT 93)
In the course of assessing the quality of the present data, comparisons 
have been made with data from the following cruises.  Station positions 
are shown in Figure 8 using these symbols:

	Present Cruise, WHP A11:  'pluses'
	SAVE leg 4:  'crosses'
	AJAX (N-S section on 1 east):  'inverted triangles'
	Atlantis II cruise 107 (W-E section on 46 south):  'triangles'

All SAVE 4 data have been considered, and only extracts from the AJAX 
and Atlantis II-107 data.  Analysis of the deep data from SAVE 4 shows 
gaps for the central stations; these were shallower stations while 
crossing the Mid-Atlantic Ridge.

Data from the western basin have been compared where potential 
temperature is cooler than 1.0°, and eastern basin data when potential 
temperature is cooler than 1.2°.

DUPLICATE ANALYSES FROM MULTIPLE TRIPS OF NISKIN BOTTLES (OCT 93)
From time to time throughout the cruise, there were casts on which the 
multi-sampler had problems in tripping Niskin bottles correctly.  This 
could result in either zero or two bottle closures for one trigger 
signal.  While this unreliability was a nuisance in some respects, and 
led to quite a lot of careful scrutiny of sample analyses to sort out 
the depths at which bottles had closed, it had the advantage of 
providing a number of duplicate samples for all the tracer analyses.  
While these are not quite independent duplicate samples, in the sense 
that they were generally analyzed in the same run by the same analyst, 
they were more independent than replicate samples drawn from the same 
Niskin bottle.  Furthermore, the fact that they were duplicates will 
have been unknown to the analyst at the time the analysis was performed.

The total number of such duplicates for which the salinity, oxygen and 
three nutrients are all good is 198 (out of 1642 samples with all 
tracers good); i.e.  about 12% of the total number of samples.  Out of 
these 198, 87 are from depths greater than 3000 meters.  The mean and 
standard deviations of these five tracers (198 samples) is as follows 
(units are µmol/kg except for salinity, percentages of full-scale in 
brackets):

		standard deviation
salinity	0.0017 (0.0009 for pressures > 3000)
oxygen		0.86 (0.3%)
nitrate		0.15 (0.4%)
phosphate	0.026 (1%)
silicate	0.30 (0.2%)

For the 87 samples from pressures greater than 3000 decibars, the 
statistic for salinity is better than for the full set; this is a 
reflection of the greater homogeneity of the water column there.  The 
statistics for the other tracers are not significantly different.


2.1  SAMPLE SALINITY MEASUREMENTS
     (S. Bacon)

On RRS Discovery cruise 199 the salinity analysis of samples was carried 
out exclusively on the IOSDL Guildline Autosal salinometer model 8400, 
modified by addition of an Ocean Scientific International peristaltic-
type sample intake pump.  The instrument was operated in the ship's 
constant temperature laboratory at a bath temperature of 24°C with the 
laboratory set to 20.5°C.  This difference in temperature was larger 
than normally employed and only arose through a misunderstanding, but 
was allowed to remain rather than disturb the salinometer again when it 
became clear that the machine was quite 'happy' operating thus.  
Standardization was effected by use of IAPSO Standard Seawater batch 
P120, of which 110 ampoules were consumed.  Two of these were 
imperfectly sealed, and were discarded; two were evidently of incorrect 
(too high) salinity, and one more was thought dubious.  These latter 
three were not used as standards.  The standardization history of the 
salinometer has been constructed, in which standardization drift is 
represented as equivalent salinity (ES) change referenced to the first 
standard measurement of the cruise.  The instrument was remarkably 
stable, not changing from its initial standardization by more than 0.001 
ES until the last ten days of the cruise, when the seas generally were 
calmer and the outside temperature increased, although it is difficult 
to associate such changes in external conditions with the observed 
behavior of the salinometer, unless the ship's power supply is 
implicated in some way.  Excluding the two bad standards, the mean 
standardization drift was 0.0007 ES, with a standard deviation of 0.0007 
ES, for 108 standards.

There were 46 pairs of replicate (i.e. from the same rosette bottle) 
samples drawn; and 210 pairs of duplicate (i.e. from different rosette 
bottles fired at the same depth) samples.  Of the duplicate pairs, 87 
were from below 3000 m.  The standard deviations of the three groups of 
sample pairs are given in table S1 below.


TABLE S1: SALINITY REPLICATE AND DUPLICATE STATISTICS

QUANTITY	STANDARD	NUMBER 
		DEVIATION	OF PAIRS
Duplicates	0.0019		208
Duplicates	0.0009		 87
(from >3000m)
Replicates	0.0008		 46

See text above table for the distinction between replicates and 
duplicates.


RECONCILIATION WITH CTD DATA, AND DATA QUALITY CONTROL (OCT 93)
(B. A. King)

Salinity samples values reported by the analyst were considered for data 
quality flagging according to three criteria:

a)  The analyst may have marked the sample as suspect or bad if 
    the analysis was unsatisfactory in some way.
b)  Sample values were compared with those from neighboring 
    stations in property-property plots.  It was found that the 
    salinity samples could be described by:
      S = 34.6760 + 0.04746 x theta for theta < 1.0 in the western basin, and by
      S = 34.6762 + 0.08052 x theta for theta < 1.2 in the eastern basin.

Note in passing that the regressions for the two basins intersect at a 
salinity of 34.676 and at a potential temperature indistinguishable from 
zero degrees.

The sample salinity anomalies (for theta < 1.0 and theta < 1.2 in the 
two basins) have been calculated relative to these regressions and 
averaged for each station.  The result is shown in Figure 9.  Station 
12296 appears to be somewhat different from the others, but was the last 
station occupied in the western basin before encountering the mid-
atlantic ridge.  Although the deep water at 12296 is slightly more 
saline than the preceding stations, it is still much fresher (order 
0.04) than the eastern basin stations.

c)  Having established the station-to-station consistency, 
    individual bad samples were sought by comparing sample values 
    with calibrated CTD salinity values.  Note that samples with 
    large residuals had already been rejected from the CTD 
    calibration procedure, but not yet flagged as suspect.  The rms 
    of the residuals was 0.001 for 430 samples at depths greater than 
    3000 meters.  Of these, 407 samples had residuals smaller than 
    0.002.  All samples with residuals greater than 0.005 were then 
    inspected on an individual basis, and a reason sought for the 
    large residual.  Mostly these were traced to regions where there 
    is a strong vertical gradient in salinity.  Many cases were found 
    where the sample salinity corresponded to the CTD salinity 
    measured a few meters deeper than where the winch was stopped and 
    the Niskin bottle closed.  It is therefore concluded that the 
    'flushing distance' for the Niskin Bottle is of the order of five 
    meters.  Commonly, the residual was 2 meters times dS/dz, the 
    vertical Salinity gradient per meter.  dS/dz could be up to 0.005 
    per meter; some residuals were as large as 0.020.  In these 
    cases, the sample salinity flag was left as 2, there being no 
    reason to doubt either the correctness of the drawing of the 
    sample, nor the accuracy of the analysis.  Examples of large 
    residuals are sample numbers 26622, 27823
    
The majority of other cases of large residuals occurred when the upcast 
CTD salinity was noisy for some reason: for example, when the ship was 
rolling and the CTD was in a significant salinity gradient.  Again, in 
such cases the sample flag was left as 2 so long as there was no other 
reason to flag the sample as suspect.

In some cases, where the CTD salinity seemed to be good, and no reason 
could be found for there to be a large residual, the sample was flagged 
as suspect or bad.

The residuals for all samples flagged as good are plotted against 
pressure in Figure 10.  (Stations 12251-12255 and 12325 are excluded 
from this figure.  This is because of particular uncertainties in the 
CTD data for those stations; this is discussed in detail in the section 
on CTD data.) Note the quite large residuals in the upper 500 m which 
arise mainly from the Niskin flushing problem.  Note also that there is 
a small but perceptible systematic variation in residuals.  This is of 
order 0.001 or less at depths greater than 1500 meters.  This could 
arise from the flushing problem, or some residual behavior of the CTD 
salinities.  It is considered to be sufficiently small that it can be 
ignored, so it remains uncorrected in the CTD data.


COMPARISON WITH HISTORICAL DATA (OCT 93)
Figure 11 shows the anomaly of the SAVE leg 4 salinities (station 
averages) with respect to the standard fit; SAVE leg 4 data are seen to 
be generally fresher, on average by 0.0015 to 0.002.  However, at the 
intersection of our cruise with SAVE leg 5, the deep salinity data were 
found to be in agreement.

Figure 12 shows the anomaly of the Atlantis II salinities, which are 
slightly higher than ours.  However, the discrepancy is not quite as 
high as it appears from the figure, which shows station averages and is 
therefore susceptible to individual large anomalies: the mean anomaly 
for 69 deep samples is 0.0025.

Note in passing that Figure 9 also shows the trend in the deep theta-S 
relation across the western basin as observed on the present cruise: 
0.0035 in salinity across 40 stations.  The rms of the station averages 
about the trend is 0.0009.


CONCLUSION
The salinity sample data are believed to be of a high standard, with 
good precision and internal consistency.  Although there are biases with 
respect to some other fairly recent historical data, we see no reason to 
doubt the absolute accuracy of our data.  We note for emphasis that all 
our samples were calibrated with respect to batch P120 of Standard 
Seawater.


2.2  SAMPLE OXYGEN MEASUREMENTS
     (P. Chapman, S.E. Holley and D.J. Hydes) 

EQUIPMENT AND TECHNIQUES
Bottle oxygen samples were taken in calibrated clear glass bottles 
immediately following the drawing of samples for CFCs.  The temperature 
of the water at the time of chemical fixation was measured to allow 
corrections to be made for the change in density of the sample between 
the closure of the rosette bottle and the fixing of the dissolved 
oxygen.  Analysis followed the Winkler whole bottle method.  The 
thiosulphate titration was carried out in a controlled environment 
laboratory maintained at temperatures between 21 and 22°C.  Thiosulphate 
normality was determined on a daily basis and whenever new reagents were 
made up.  Duplicate samples were taken on every cast; usually these were 
from the deepest four bottles.

For the early stations, the end point was determined by an automatic 
photometric method manufactured by SIS (Germany).  After station 12253, 
however, the instrument began giving erroneous endpoint readings since a 
distinct yellow colour was sometimes still visible in the titration 
flasks.  This was not consistent, and some analyses within each run 
appeared to titrate correctly; however, all samples from stations 12253, 
12254, 12255, and 12257 have been flagged as suspect.  For stations 
12258 to 12337, i.e. the bulk of the cruise, an "amperometric titration 
to a dead stop" following the method of Culberson and Huang (1987) was 
used.  A Metrohm Titrator and a Dosimat 665 (10 ml) automatic burette 
was employed.  Titration volumes in deep waters were approximately 5 ml 
and the smallest increment from the burette was 2 microlitres.

The volume of oxygen dissolved in the water was converted to mass 
fraction by use of the factor 44.66 and an appropriate value of the 
density; corrections for the volume of oxygen added with the reagents 
and for impurities in the manganese chloride were also made as described 
in the WOCE Manual of Operations and Methods (Culberson, 1991).


REPRODUCIBILITY OF MEASUREMENTS
Approximately 1900 samples were taken during the cruise; in addition, a 
large number of duplicates were analyzed.  Statistics on the duplicates 
are given in Table O1.  These include both duplicates taken from the 
same bottle (replicates) and those taken from different bottles fired at 
the same depth and invariably unknown to the analysts.

While the photometric method was being used, 22 samples were taken from 
separate bottles all fired at a depth of 2500 m at station 12240 (Table 
O1).  The data gave a standard deviation of 0.63 µmol, or 0.3%.  
However, 12 pairs of duplicates taken from the same bottle for stations 
12250-12256 gave a mean difference of 1.2 µmol with a standard deviation 
of 1.29 µmol (approximately 0.56%, Table O1).  Duplicates from 223 pairs 
of samples taken from the same bottle later in the cruise while the 
amperometric method was in use had a mean difference of 0.64 µmol, and 
standard deviation of 0.85 µmol, while 13 samples from 5455m from 
station 12277 gave a standard deviation of 0.35 µmol (0.15%, Table O1).

A further series of multiple samples was taken from different bottles 
fired at the same depth as a result of double trips by the rosette.  The 
results of these are also given in Table O1.  The mean difference for 
166 sets taken over all depths and analyzed by the amperometric method 
was 0.57 µmol;  the standard deviation of the differences was 0.65 µmol.  
These figures are not significantly different from duplicates taken from 
the same bottle (replicates).


COMPARISONS WITH HISTORICAL DATA
Data taken at on this cruise on stations 12271-12274, 12282-12286, and 
12296-12299 were compared SAVE stations 289-293, 260-264, and 200-203 
respectively.  Additionally, stations 12313-12316 were compared with 
data obtained at AJAX stations 46 and 47 near the Greenwich meridian.  
Some of this is shown in Figs. 3 and 4.  Apart from difference in the 
near surface data resulting from changes in water masses in the area, 
there is a large measure of agreement.  However, at the deepest levels 
the present cruise data at a given potential temperature (or salinity) 
shows an offset of between 2 and 6 µmol kg-1, in all cases less than the 
historic data.  We are currently investigating the cause of these 
offsets.


REFERENCES

CULBERSON, C.H. and S. HUANG, 1987.  Automated amperometric oxygen 
  titration. Deep-Sea Research, 34, 875-880.
CULBERSON, C.H. 1991.  15 pp in the WOCE Operations Manual (WHP 
  Operations and Methods) WHPO 91/1, Woods Hole.


TABLE O1: Statistics of duplicates and replicates obtained by both the 
          photometric and amperometric methods.  Sample depths are given where 
          appropriate.

stn(s)	 number	depth(s)	oxygen concentration µM/kg
		m	mean	(diff)	std dev	%mean
Photometric method
12240	   22	2500	208.5		0.63	0.3
12250-56   12	 all		1.2	1.29	0.56
Amperometric method
12277	   13	 234	230.1	0.35		0.15
12258-337 223	 all		0.64	0.85	0.40
12258-337 166	 all		0.57	0.65	0.30


RECONCILIATION WITH CTD DATA, AND FURTHER DATA QUALITY CONTROL (OCT 93)
(B. A. King)

Oxygen samples were assessed for data quality and data quality flagging 
in the following manner:

a)  The analyst may have flagged the sample as suspect or bad.
b)  The data were plotted in station groups, with both pressure and 
    potential temperature as the vertical coordinate. This enabled 
    outliers to be identified and investigated. Very commonly, some 
    other evidence was found which resulted in a flag of suspect or 
    bad. However, samples were not flagged as suspect solely because 
    they were outliers.
c)  Sample values believed to be good were used for calibration of 
    CTD oxygens, as described elsewhere. Residuals between sample 
    oxygens and CTD oxygens were then calculated and inspected on a 
    sample by sample, station by station, basis. On the basis of this 
    inspection, a small number of samples previously marked as suspect 
    were promoted to good. More commonly, samples were downgraded from 
    good to suspect, or suspect to bad. It was recognized that in 
    certain parts of the water column, particularly where vertical 
    gradients were strong, quite large residuals could genuinely 
    arise. These could arise from a number of sources, including the 
    following

  i) the Niskin Bottle flushing length, discussed in the salinity section
 ii) the relatively slow response of the CTD sensors
iii) mismatch between oxygen samples collected on the upcast, and CTD 
     oxygen values collected on the downcast (see the discussion in the CTD 
     section)

Samples with large residuals (>5 µmol/kg) were permitted to retain a 
good flag if it was believed that one of these effects was responsible 
for the size of residual.

d)  Sample numbers for which other tracers had been found to be 
    suspect (especially nutrients) were given special scrutiny in 
    oxygen, and vice-versa, and flags adjusted where necessary.

FINAL RECONCILIATION WITH CTD DATA (OCT 93)
After the data quality procedures had been completed, the CTD oxygens 
were re-calibrated using, in general, only data flagged as good.  
However, there were some exceptions.  For stations 12253-12257, there 
were not enough good data (see the analysts' discussion above); 
accordingly those stations were calibrated using data flagged as 
suspect.  The list of suspect (flag 3) sample numbers used in CTD 
calibration is as follows: 

25301, 25302, 25303, 25304, 25305, 25307, 25308, 25309, 25310, 25312, 
	25313, 25316, 25317, 25318, 25319
25401, 25402, 25403, 25404, 25406, 25407, 25408, 25410, 25411, 25412, 
	25413, 25416, 25417, 25419
25501, 25502, 25503, 25504, 25505, 25506, 25507, 25508, 25509, 25510, 
	25511, 25512, 25513, 25514, 25515, 25516, 25517, 25518, 25519, 
	25603
25701, 25702, 25703, 25704, 25706, 25707, 25708, 25710, 25711, 25712, 
	25713, 25714, 25715, 25716, 25717, 25718, 25719, 25720, 25721, 
	25722

Similarly, there are sample data believed to be good, which were 
unsuitable for use as CTD calibration samples, mainly because of the 
reasons given in (c) above.  The following good (flag 2) samples were 
excluded from the CTD calibration:

25824
25914, 25915, 25924
26622
26720
27230
27736
27921
29428
30119, 30120
30213, 30218, 30219
30322
30520, 30521
30614, 30615, 30619
30720
30820
31119, 31120
32117
33210, 33214
33315

Finally, the CTD calibration sometimes lacked a good sample near the 
surface (for example on stations 12269 and 12270, where there were 
multi-sampler problems).  In these cases, plausible near-surface sample 
values were 'invented', solely for the purpose of CTD calibration, and 
based either on neighboring stations or slight over-saturation (2%) of 
near-surface water.  The list of sample numbers for which this was done 
is as follows:

25108, 25109
26010, 26011, 26012
26914, 26915, 26916
27013, 27014, 27015

SUMMARY OF SAMPLE MINUS CTD RESIDUALS (OCT 93)
The residuals between all samples eventually flagged as good, and the 
CTD oxygens, are summarized in Table O2:


TABLE O2: Residuals of sample-CTD oxygens, averaged into 500 meter depth bins.

PRESSURE	MEAN	STD DEV	# IN SAMPLE
    >6000	-1.41	0.49	   4
5500-6000	-2.34	1.12	  19
5000-5500	-0.73	1.16	  93
4500-5000	-0.11	1.65	  70
4000-4500	 0.67	1.55	  72
3500-4000	 0.54	1.83	  79
3000-3500	 1.14	1.46	  83
2500-3000	-0.01	1.80	  75
2000-2500	 0.71	2.00	 147
1500-2000	 0.65	1.94	 165
1000-1500	-1.10	1.73	 165
 500-1000	-0.98	2.60	 175
   0- 500	 0.28	3.30	 532
All		 0.03	2.66	1686
All>3000	 0.14	1.73	 420

Note that 1679 out of 1686 samples have a residual smaller than 10 µmol/kg.


TEMPERATURE USED FOR CONVERTING µMOL/L TO µMOL/KG (OCT 93)
Requirement: Oxygen concentrations were reported by the analysts in 
µmol/l, and need to be converted to µmol/kg by introducing the density 
of the water at the time when the oxygen fixing reagents were added on 
deck.  The density is computed from the sample salinity and an estimate 
of the temperature at time of fixing.  Note that for a salinity of 35, 
0.1% in density is equivalent to 4° at 20°C and 8° at 2°C.  We should 
therefore aim to get the temperature at time of fixing correct to about 
2° or 4°. 

An attempt was therefore made to measure the temperature of the oxygen 
sample at the time that the oxygen fixing reagents were added on deck.  
This was done by flushing a spare sample bottle with water from the 
Niskin Bottle, and measuring the temperature of the sample with a PRT; 
temperatures were recorded for 80% of the oxygen samples drawn.  These 
temperatures are reported as OXYTMP in the .SEA file.

For deep samples, OXYTMP is always warmer than THETA, the CTD potential 
temperature measured at the time the Niskin Bottle is closed.  This is 
what would be expected.  However, it was found that for many shallow 
samples, especially in the eastern basin where sea surface temperatures 
could be as high as 20 degrees, OXYTMP was cooler than THETA.  On some 
occasions, this could be traced to night-time stations where the air 
temperature was up to 4 or 5 degrees cooler than SST; on other occasions 
there was no apparent reason why OXYTMP should be any cooler than THETA, 
so the observations remain as a mystery.  We therefore conclude that 
these apparently improbable values result from inconsistent or otherwise 
inadequate procedure for measuring OXYTMP.  For example, the probe may 
have been permitted to be subject to evaporation, or incomplete 
temperature equilibration.  This procedure will be investigated further 
on subsequent cruises.

Note in passing that during the cruise, the probe used to measure OXYTMP 
failed.  After repair, it was calibrated against a SIS digital reversing 
thermometer at 20 points between zero and 30°.  The resulting linear 
calibration had residuals of no greater than 0.1°.

In reaching a final decision on which temperature to use for converting 
volume to mass units, there are thus two main considerations:

a)  OXYTMP is unavailable for about 20% of samples.  This includes 
    a series of stations in mid-cruise (12272-12277) between the 
    failure of the probe and the introduction of the repaired probe.  
    It is necessary to use some method for creating OXYTMP for samples 
    where it was not measured.
b)  We have some reservations about the reliability of individual 
    OXYTMP measurements.
    
It was therefore decided to use a simple function of THETA to predict 
the OXYTMP used for data conversion, this function being based on the 
observed OXYTMP values.  This has the advantages of providing a complete 
set of OXYTMPs, and removes the vulnerability to a single poor 
temperature determination on deck.  The chosen fit was

	THETA > 12 : OXYTMP = THETA
	THETA < 12 : OXYTMP = 3.612 + 0.699 x THETA

The coefficients in the regression equation are the least squares fit to 
1296 samples with THETA < 12, constrained to pass through 
OXYTMP=THETA=12 degrees.  Thus OXYTMP was found to be about 3.5 degrees 
warmer than THETA when THETA was near zero.

The residuals of 'measured' OXYTMP about 'predicted' OXYTMP are shown in 
Figure 13 (measured minus predicted), where they are plotted against 
THETA.  We are satisfied that the resulting predictions are adequate for 
converting the oxygen units.  For THETA cooler than 12 degrees, the 
residuals have zero mean, standard deviation 0.9 and all but one 
residual is smaller than 4 degrees.  For THETA warmer than 12, the mean 
residual is -0.9, standard deviation 1.3 and 153 out of 156 residuals 
are within 4 degrees of the mean.

We repeat for clarity and emphasis, that the OXYTMP reported in the .SEA 
file is the observed value, when present.  However, the value used for 
conversion of oxygen concentration units was calculated from THETA 
according to the above formulae.  These formulae are not expected to be 
definitive for all ocean basins.  The amount of warming expected as a 
Niskin Bottle is hauled through, say 3000 meters of the water column 
will clearly depend on the temperature profile.  However, we believe our 
present prescription to be amply adequate for the present purpose.

FURTHER COMPARISONS WITH HISTORICAL DATA (OCT 93)
Further comparisons of sample data with historical data have been 
undertaken using anomalies with respect to average conditions, as 
introduced in the discussion of salinity.  The standard fits were 
defined using least-squares fits to the data from A11, using data where 
theta < 1.0 in the western basin, and theta < 1.2 in the eastern basin.  

The resulting theta-oxygen relations were then (in µmol/l)
	western basin:	O2 = 223.90 - 17.53 x theta
	eastern basin:	O2 = 216.14 +  4.57 x theta
Using a density of 1.028 kg/l, these are equivalent to (in µmol/kg)
	western basin:	O2 = 217.80 - 17.05 x theta
	eastern basin:	O2 = 210.25 +  4.45 x theta

Note that not only are the deep oxygen values somewhat different between 
the two basins, but that the vertical gradients are of opposite signs.  
The intersection of the regressions is at a potential temperature of 
0.35, where the oxygen value is 212 µmol/kg.

The A11 data may now be compared with other data and inspected for bias 
by comparing the anomalies with respect to these standard fits, 
illustrated in Figures 14 to 17.

Relative to A11 data (Figure 14), the following represent the median 
offsets:

Figure 15 SAVE leg 4	 + 4.0 (± 1.9) µmol/kg
Figure 16 AtlantisII-107 + 1.0 (± 1.7) µmol/kg
Figure 17 AJAX 		 + 7.0 (± 0.75) µmol/kg

Our data seem to be quite clearly lower in oxygen than the AJAX and SAVE 
leg 4 data; the comparison with Atlantis II data is somewhat 
inconclusive.  The reason for the biases between the data sets is 
something of a mystery; we merely note them here.


2.3  NUTRIENTS
     (D.J. Hydes, P. Chapman and S.E. Holley)

EQUIPMENT AND TECHNIQUES
The nutrient analyses were performed on an Alpkem Corporation Rapid Flow 
Analyzer, Model RFA-300.

The methods used were: - Silicate:  the standard AAII molybdate-ascorbic 
acid method with the addition of a 37°C heating bath (Hydes 1984) to 
reduce the reproducibility problems encountered when analyzing samples 
of different temperatures, noted on an earlier cruise when the standard 
Alpkem method was used (Saunders et al 1991, c.f. Joyce et al 1991).  
Phosphate used the standard (Murphy and Riley 1962) reagents and reagent 
to sea water ratios but with separate additions of ascorbic acid and 
mixed molybdate - sulphuric acid - tartrate to overcome the problem of 
the instability of a mixed reagent including ascorbic acid.  Nitrate was 
determined using the standard Alpkem method.

Previous experience has shown that better reproducibilities are achieved 
when the instrument is run in a laboratory with a stable temperature.  
The Alpkem was located in the new constant temperature laboratory on 
Discovery.  The temperature was maintained between 21 and 22°C.  A 
drawback of this location was that the large air circulation in the 
laboratory leads to enhanced evaporation of samples in the open cups 
sitting in the analyzer tray, and possibly to some contamination due to 
dust circulating in the air-stream.  This was ameliorated by fitting a 
cardboard skirt round the sample tray lid.


SAMPLING PROCEDURES
Sampling of nutrients followed that for trace gases (CFCs on this 
cruise) and oxygen.  Samples were drawn into virgin polystyrene 30ml 
Coulter Counter Vials (ElKay).  These were rinsed three times before 
filling.  Samples were then analyzed as rapidly as possible after 
collection to avoid build up of a sample back log.  Samples cups of 2.0 
ml capacity were used.  These were rinsed once by filling completely 
before filling with analyte.  Tests carried out on the cruise showed 
that samples from all depths stored for a week in a refrigerator at 4°C 
were not significantly effected by storage.


CALIBRATION AND STANDARDS
The calibrations of all the volumetric flasks used on the cruise were 
checked before packing and these were re-calibrated if necessary.

Calibrations of the three Finn pipettes used on the cruise were checked 
before packing.  The six Eppendorf fixed volume pipettes were delivered 
too late to be calibrated before the cruise.  However in use no 
difference was detectable between the results achieved with the Finn 
pipettes and Eppendorfs.


NUTRIENT STANDARDS 
Nutrient primary standards were prepared from salts dried at 110°C for 
two hours and cooled over silica gel in a dessicator before weighing.  
Precision of weighing was to better than 1 part per thousand.


NITRATE 
0.510g of potassium nitrate was dissolved in 500 ml of distilled water 
in a calibrated volumetric PP flask at a temperature of 21-22°C.


NITRITE  
0.345g of sodium nitrite was dissolved in 500 ml of distilled water in a 
calibrated volumetric PP flask at a temperature of 21-22°C.


PHOSPHATE
0.681g of potassium dihydrogen phosphate was dissolved in 500 ml of 
distilled water in a calibrated volumetric PP flask at a temperature of 
21-22°C.  Working standards were prepared from a secondary standard made 
by diluting  5.00 ml of the primary standard measured using a Finn 
pipette Digital 1.00 to 5.00 ml adjustable volume, in a 100 ml 
calibrated glass volumetric flask.


SILICATE
0.960g of sodium silica fluoride was dissolved in 500 ml of distilled 
water in a calibrated volumetric PP flask at a temperature of 21-22°C.  
Dissolution was started by grinding the fluoride powder to a paste with 
a few drops of water in 30 ml polythene beaker using a plastic rod for 
three to four minutes.


SECONDARY CALIBRATION STANDARDS.
A uniform set of six mixed secondary standards were prepared in 
artificial seawater, Concentrations (µM) were Nitrate 40, 30, 20, 10, 
and 0; Phosphate 2.5, 2.0, 1.5, 1.0, 0.5 and 0, Silicate 150, 100, 75, 
50, 25 and 0 up to station 12288 and 150, 120, 90, 60, 30 and 0 
thereafter.

The artificial seawater was a 40ppt solution of Analar grade Sodium 
Chloride.  Nutrients were undetectable in these solutions relative to 
Ocean Science International (OSI) Low Nutrient Sea Water which contains 
0.7µM Si, 0.0µM NO3 and 0.0 µM PO4.  On one occasion the solution was 
found to contain 0.6µM PO4 and consequently was not used.


ESTABLISHMENT OF A QUALITY CONTROL QC SAMPLE
At a test station 12240 occupied on 26 December a large volume of deep 
water was collected with the idea of using this as a quality control 
standard when its stability had been verified.  Samples of this water 
where run at intervals over the next two weeks.

From station 12291 onwards a sample of 12240 water was measured as a 
"QC" sample on each analyzer run.  The scatter of the data are shown in 
Fig 5.  Silicate returned a consistent result with occasional flyers.  
The phosphate results suggest that the first (up to 12301) and second 
(up to 12319) one liter sub-sample were unstable but the third sample 
was stable.  This may be due to the surface of the polythene bottle 
storage equilibriating with the sample.  The sharp shift in the apparent 
nitrate concentration in the QC between stations 12311 and 12312 is 
currently inexplicable.  It does not correspond to a change in primary 
standard concentration.  It was difficult to detect in the contour 
plots, but does appear to be present when concentrations were compared 
along isopycnal surfaces.


REPRODUCIBILITY
For the QC standard 189 measurements were made.  The means were Silicate 
78.85, Nitrate 28.85, Phosphate 1.79, percent standard deviations 
Silicate 1.05, Nitrate 2.45, Phosphate 2.35.

For 10 replicates of the top standard run after station 12337 the 
percent standard deviations were Silicate 0.22, Nitrate 0.25, Phosphate 
1.1.


REFERENCES

HYDES, D.J.  1984 A manual of methods for the continuous flow 
  determination of ammonia, nitrate-nitrite, phosphate and silicate in 
  seawater. Institute of Oceanographic Sciences Report No 177, 40pp.
JOYCE, T., CORRY, C. and STALCUP, M. 1991 Editors of WOCE operations 
  manual, part 3.1.2 Requirements for WOCE hydrographic programme data 
  reporting. US WOCE WHP Office 90-1, 71pp.
MURPHY, J and RILEY, J.P. 1962 A modified single solution method for the 
  determination of phosphate in natural waters. Anal. Chem. Acta, 27,31 
  36.
SAUNDERS, P.M., GOULD, W.J., HYDES, D.J. and BRANDON, M. 1991 CTDO and 
  nutrient data from Charles Darwin cruise 50 in the Iceland Faroes 
  region. Institute of Oceanographic Sciences Deacon Laboratory, Report 
  No 282, 74pp


FURTHER DATA QUALITY CONTROL OF NUTRIENT SAMPLES (OCT 93)
(B. A. King)

Data quality control was tackled in a similar way as for salinity and 
oxygen, but of course there is no CTD sensor to assist in the rejection 
of poor sample values.  Initially therefore, property-property plots 
were used to identify the sample numbers of outliers.  These were mainly 
with theta or pressure as one coordinate, but plots of pairs of 
nutrients were also used.  Outliers identified by this means were then 
inspected individually, and reasons sought for why they might have 
occurred.  Suspect or bad flags were assigned to some or all of the 
nutrients in a total of 18 samples.


CONVERSION BETWEEN MASS AND VOLUME UNITS (OCT 93)
The appropriate density for converting volume to mass units of nutrient 
analyses is the density in the lab where known volumes of sample were 
measured.  Using a lab temperature of 21° and a mean salinity of 35, 
gives a density of 1.025 kg/l; density changes due to salinity variation 
amount to about 0.1%, and have been ignored.  A density of 1.025 kg/l 
has been used to convert the data reported in the .SEA file.


INTERNAL CONSISTENCY AND COMPARISON WITH HISTORICAL DATA(OCT 93)
As with the other tracers, standard regressions of the deep data onto 
potential temperature were defined in each basin, and used for comparing 
station data within and outside the cruise.


The standard fits were as follows (µmol/l):

western basin:	NO2+3  = 33.88 - 1.42 x theta
		phspht = 2.228 - 0.121 x theta
		silcat = 126.90 - 17.85 x theta
eastern basin:	NO2+3  = 33.523 - 3.91 x theta
		phspht = 2.319 - 0.303 x theta
		silcat = 134.12 - 35.58 x theta
At a density of 1.025 kg/l, these are equivalent to (in µmol/kg)
western basin:	NO2+3  = 33.05 - 1.385 x theta
		phspht = 2.173 - 0.118 x theta
		silcat = 123.80 - 17.41 x theta
eastern basin:	NO2+3  = 32.705 - 3.815 x theta
		phspht = 2.262 - 0.296 x theta
		silcat = 130.85 - 34.71 x theta


Using the anomalies relative to these fits, it was possible to monitor 
the variation in the deep properties of the calibrated nutrient data.  
Note in passing that the eastern basin nitrate data fell in two 
families, offset from one another (discussed below).  The regression was 
determined from just one family of data.


NITRATES (Oct 93)
A plot of the station average anomaly against station number made it 
immediately apparent that there was a problem (of the order of 1 µmol/l) 
in the consistency of standardization between groups of stations.  
Furthermore, abrupt changes in the deep nitrate values corresponded to 
changes in the nitrate value in the QC sample shown in Figure 5.  
Further investigation showed that all the significant changes in the 
apparent deep nitrate values occurred at stations where some adjustment 
had been made to the auto-analyzer.  For example, adjusting the 
sensitivity to keep the instrument response to the top standard near the 
top of the scale, or a reactivation of the cadmium column. 

That such adjustments should lead to changes in the calibrated sample 
data is clearly not entirely satisfactory.  After all, the whole point 
of standardization is that the concentration in the sample is being 
determined relative to that of the standard, and should be independent 
of the instrument settings used.  Clearly the adjustments that were made 
had different affects on the standards and on the samples.  The reason 
for this is not known. 

The cadmium column was reactivated before the analysis runs for stations 
12284, 12312 and 12322.  The first two of these were marked by a fall in 
the apparent concentration of deep sample nitrates.  Calibration of the 
deep samples appeared unchanged after the third event.

As part of the investigation of the standardization of the auto-
analyzer, the instrument peak heights for the various standard 
concentrations came under renewed scrutiny.  Time series plots of these 
peak heights were found to be a useful way of monitoring the performance 
of the instrument, and led to the identification of some hitherto 
unnoticed poor standard values.  Joint inspection of the peak heights 
for the standards with the calibrated sample values was found to be 
illuminating.  For example, it enabled a poorly determined baseline to 
be identified and corrected, which led to adjustment of some sample 
values. It also facilitated the correlation of instrument changes with 
apparent, but what we now know to be spurious, changes in deep sample 
values.  It is our intention that on future cruises we will maintain 
this practice of carrying the information about instrument 
standardization and adjustment through to the inspection of sample data.

Another result of the scrutiny of the standard peak heights was some 
investigation of the appropriate order of polynomial that should be used 
in the calibration.  Unfortunately, the SOFTPAC software used to apply 
the calibration and drift corrections does not seem to have a facility 
for displaying the residuals between the standard concentrations and the 
fitted polynomial.  Instead, the standard concentrations and the fitted 
polynomial are displayed on a graph, which ranges over the full scale of 
the variable.  This makes it very difficult to determine the relative 
merits of one polynomial compared with another, and also makes it 
difficult to identify poor values that should be discarded from that 
particular set of calibration data.  For example, a standard which has a 
lack of fit of 0.5 µmol/l should probably be discarded from the fit, but 
is hard to detect in the graphical display.  Accordingly, the standard 
peak heights were reanalyzed in Excel spreadsheets, and the following 
conclusions drawn:

a)  The instrument peak heights should be calibrated using a second 
    order polynomial fit. The coefficient of the quadratic term is 
    positive. After fitting the polynomial to six standard 
    concentrations, the rms error is of the order of 0.1 µmol/l.
b)  In a number of stations, poor peak heights for individual 
    standards had been retained in the ship board calibration of the 
    data, which should have been discarded. This was made apparent by 
    inspection of the residuals after fitting the quadratic 
    polynomial. Although for future cruises errors of this size should 
    be eliminated, they were not considered to have had sufficient 
    impact to make it worthwhile re-calibrating the data.

Fixing the offsets arising from instrumental adjustment: As described 
earlier there are spurious changes in the deep sample values, associated 
with auto-analyzer adjustments. These have been fixed as follows:

a)  Stations 12284 to 12287: This group of stations, immediately 
    after a reactivation of the cadmium column, were low relative to 
    adjacent stations.  The jump to lower values was clearly 
    associated with the change to the column, but it is not clear why 
    the values increase again.  The average anomaly of deep nitrates 
    for these four stations were compared with the average for four 
    stations on either side (12279-12283 and 12288-12291) and found to 
    be 1.56 µmol/l low.  Using a mean deep nitrate value of 33.5 
    µmol/l, it was decided to scale all the sample nitrates for those 
    four stations by a factor of 1.046.
b)  Stations 12312 to 12337: This group again follows a 
    reactivation of the column, which was combined with an adjustment 
    to the sensitivity of the instrument, and has lower values than 
    preceding stations; however the nitrates do not appear to return 
    to a higher value.  The nitrate value in the QC sample shows the 
    same behaviour.  There was sufficient difference between the 
    stations before and after 12312 that the standard regression for 
    nitrate on potential temperature in this basin was determined from 
    one group only, stations after 12312 being chosen.  It was decided 
    that one group of eastern basin stations should be adjusted 
    relative to the other to bring them into agreement.  There being 
    no absolute means of deciding which were superior, the adjustment 
    was applied to stations 12312 and following.  Comparison of the 
    deep nitrate anomaly for 12312-12337 with 12302-12311 indicated 
    that a correction of 1.46 µmol/l was required.  With a mean 
    concentration of 30 µmol/l, this led to a scaling by a factor of 
    1.048 for all nitrate data for station 12312 to the end of the 
    cruise.  Note that since the standard regression had been 
    calculated on data from these stations, all the deep eastern basin 
    data are now about 1.5 µmol/l higher than the standard fit.
    

SILICATES (Oct 93)
A plot of deep silicate anomaly against station number showed that as 
with nitrates there were some stations which were offset compared with 
adjacent stations. Unlike the nitrates, however, the silicate values did 
not seem to be so susceptible to adjustments of the instrument. Five 
stations stood out in particular, and these were examined and adjusted 
as follows:

a)  Station 12287: Examination of the calibration peak heights 
    showed that they were about 10% low compared with preceding 
    stations; there had clearly been a loss of sensitivity in the 
    instrument for the analysis of this station. Accordingly, 
    silicates for this station were scaled by a factor of 0.989 (-1.4 
    µmol/l at a concentration of 125 µmol/l) to bring the deep values 
    into agreement with stations 12284-12290.
b)  Stations 12318, 12319, 12323, 12325. These stations all had 
    unusually high anomalies for the deep silicate. 12318, 12323, 
    12325 all show up as spuriously high in the QC values of silicate 
    shown in Figure 5. 12318 and 12319 also had lower than usual peak 
    heights for the standardization. We therefore decided to reduce 
    all four stations by a uniform factor, to bring their mean anomaly 
    into agreement with the average for stations 12320, 12321, 12322, 
    12324, 12326.  The required adjustment was -2.092 µmol/l at a mean 
    value of 108 µmol/l, so a scaling factor of 0.981 was applied.


PHOSPHATES (Oct 93)
No special adjustments were considered necessary for the phosphate data. 
The relatively greater uncertainty in the phosphate measurements means 
that the kind of corrections identified for nitrate and silicate are 
either unnecessary or undetected.


COMPARISON WITH HISTORICAL DATA (OCT 93)
The internal consistency of the nutrient data (albeit after corrections 
to some stations) and comparison with other cruises is summarized in 
Figures 18 (nitrate), 19 (silicate) and 20 (phosphate); each figure has 
three parts (a) is this cruise, (b) is SAVE leg 4 data and (c) is AJAX 
data.  These figures enable offsets to be identified, as well as showing 
the degree of scatter in each data set. The symbols show station 
averages of the deep sample anomalies. 

The relative offsets are further summarized in Table N1.  The data were 
sorted into bins of size 0.25, 0.5, 0.025 µmol/l for nitrate, silicate 
and phosphate, and the center value of the bin containing the median is 
shown.  Standard deviations of the station average anomalies are given 
in brackets.  The standard error of the estimate of the mean/median is 
somewhat smaller than the standard deviation.


TABLE N1: Medians of station-average offsets between sample data and standard 
          regressions, for various data sets. Units are µmol/l. Values in 
          brackets are standard deviations of the station average anomalies 
          around the mean.

		A11		SAVE		AJAX
nitrate (west)	 0.25(0.39)	-0.25 (0.73)	none
nitrate (east)	 1.5 (0.22)	 0.75 (0.24)	0.5 (0.09)
silicate	-0.5 (1.33)	 2.5  (1.53)	0.5 (0.37)
phosphate	   0 (0.025)	 0.125(0.06)	0.05(0.015)


Compared with SAVE, our nitrates are seen to be about 0.5 µmol/l (1.5%) 
high, silicates 2.5 µmol/l (2%) low and phosphates 0.125 µmol/l (5%) 
low.  These differences are all significantly more than the internal 
uncertainty in the data.  This demonstrates that our ability to maintain 
reproducibility over the period of a cruise is rather better than our 
confidence in the absolute accuracy of the data.  The upper limits for 
accuracy given in the WOCE requirements are 1% for nitrate, 3% for 
silicate and 2% for phosphate.


2.4  CFC-11, CFC-12, and CFC-113
     (D. Smythe-Wright, S.M. Boswell and D. Price) 

SAMPLE COLLECTION
All samples were collected from depth using 10 liter Niskin bottles.  
These had been cleaned prior to the cruise using a high-pressure water 
jet.  All 'O' rings, seals and taps were removed, washed in Decon 
solution and propanol then baked in a vacuum oven for 24 hours.  
Cleaning and reassembling of the bottles was carried out at the 
commencement of the cruise to minimize contamination due to long 
storage.  Of the 24 bottles initially assembled three had to be replaced 
due to leakage.  None of the 27 working bottles showed a CFC 
contamination problem during the entire cruise.  All bottles in use 
remained outside on deck throughout the cruise, those not in use were 
stored in aluminum boxes inside the hanger where there was a free flow 
of air to minimize contamination.


EQUIPMENT AND TECHNIQUE
Chlorofluorocarbons CFC-11, CFC-12 and CFC-113 were measured on a total 
of 46 stations.  The analytical measuring technique was a modification 
of that described in Smythe-Wright (1991a & b).  In the modified system 
trapping was achieved using a 10 cm Poracil B trap cooled to below -
45°C.  Subsequent de-sorption was by means of a water bath at 100°C.  
The trap was positioned on the exterior of the GC oven and not on the 
extraction board as in the original system.  Valves V6 and V7 were 
replaced respectively with automated 8 port and 6 port Valco valves 
sited inside the GC oven to give better chromatographic resolution.  
Gases were forward flushed off the trap into a 3 m pre-column and 
subsequently chromatographcally separated using a 75 m long DB 624 
megabore column.  The pre-column was of the same material as the main 
column.  Samples for analysis were drawn first from the Niskin bottles 
and stored under clean seawater.  The analysis was completed mostly 
within 12 hours of the samples coming on board.  Duplicate samples were 
run on most but not all casts due to the long analytical turn over time.  
Air samples were run daily from an air intake high up on the foremast.  
Air was pumped from this location through a single length of Dekoron 
tubing using a metal bellow pump.


CALIBRATION
All CFC-11 and CFC-12 analyses were calibrated using 12 point 
calibration curves constructed from a gas standard calibrated by Weiss 
at SIO.  This standard was contained in an Airco spectra seal cylinder 
as recommended in WHP, 1991.  CFC-113 analyses were calibrated in a 
similar fashion using a compressed air standard prepared at the JRC and 
calibrated by Haine at PML. 


CONTAMINATION
Because of a delay in customs clearance of the airfreight, the CFC 
equipment was delivered to the ship less than 24 hours before departure.  
This delay had a knock-on effect and compounded a number of teething 
problems, mainly due to two blocked valves and a contamination problem 
which masked the CFC-12 chromatographic peak.  This resulted in the loss 
of data from a number of stations at the beginning of the cruise.  The 
nature and source of the contamination problems was never totally 
discovered.  It seemed to be related to the aquarium baths and the 
nontoxic seawater supply used for storing the syringes prior to 
analysis.  The problem appeared some days after sailing and was overcome 
chromatographically by reducing the carrier gas flow and thereby 
separating the contamination from the CFC-12 peak.  This meant that the 
overall analysis time was lengthened to 25 minutes and consequently 
restricted CFC analysis to every other CTD cast.


COMPARISON WITH HISTORICAL DATA
Data accuracy was checked by comparison with SAVE leg 4 and 5 data and 
with data from the Ajax experiment.  Some comparisons are given in 
Figure 6.  Since four years has elapsed since these programmes some 
deviation in the data was expected particularly in the surface and 
deepest waters.  In all cases deviations were consistent with the 
increase in atmospheric concentrations over the four-year period.


REFERENCE

SMYTHE-WRIGHT, D., 1990a. Chemical Tracer Studies at IOSDL I. The design 
  and construction of analytical equipment for the measurement of 
  Chlorofluorocarbons in seawater and air. Institute of Oceanographic 
  Sciences Deacon Laboratory Report No 274, 78 pp.
SMYTHE-WRIGHT, D., 1990b. Chemical Tracer Studies at IOSDL II. Method 
  manual for the routine shipboard measurement of Chlorofluorocarbons in 
  seawater and air. Institute of Oceanographic Sciences Deacon Laboratory 
  Report No 275, 64 pp.
WHPO, 1991 WOCE Operations Manual.  WHP Office Report WHPO 91-1 WOCE 
  Report No 68/91.  Woods Hole Mass, USA.


2.5  SAMPLES TAKEN FOR OTHER CHEMICAL MEASUREMENTS

A) OXYGEN AND HYDROGEN ISOTOPE RATIOS
   (S.M. Boswell)

A total of 241 samples were collected from 12 stations for isotope 
analysis by UEA.  These included 18 duplicate samples from station 
12333.  Samples were collected directly into 50 ml glass vials following 
an initial rinse and two filling/emptying method.  The caps were then 
sealed using parafilm and stored in the refrigerator.  A total of 8 
samples from the first three stations were lost when the fridge opened 
in rough weather.  Samples thereafter were stored in the cold store.

b) IODINE
   (P. Chapman) 

A total of 78 samples were collected from full water depth casts at 
Stations 12255, 12288, 12305 and 12335.  These will be analyzed by Dr G 
Luther, University of Delaware USA.

iodide		 concentration of iodide, nmoles per liter 
stdv_I-		 standard deviation of iodide

iodate		 DPP concentration of iodate, nmoles per liter
stdv_IO3-	 standard deviation of iodate

spectro_IO3	 spectrophotometric concentration of iodate, nmoles per liter
stdv_spec_iodate standard deviation of iodate

sum -Ired	 concentration of total iodine, nmoles per liter
stdv_sum-Ired	 standard deviation of total iodine

COLLECTION
Samples were collected from routine hydrocasts.  Care was taken to draw 
samples after the dissolved oxygen reagents were removed from the 
hydrolab to avoid any potential sources of contamination during 
sampling.

ANALYSES
Iodide and iodate concentrations were determined using polarographic 
and voltammetric methods.  Iodide (I-) was measured using cathodic 
stripping square wave voltammetry (CSSWV) [Luther et. al., 1988].

Iodate (IO3-) was measured using differential pulse polarography (DPP) 
[Herring and Liss, 1974].

Total iodine (_Ired) was measured using CSSWV [Campos (1997)]. 

The instrument minimum detection limits in seawater for I-, IO3-, _Iox 
and _.Ired using polarography are 0.2, 20, and 5 nM respectively.

For detailed methods please consult (Farrenkopf, 1997 -- Dissertation 
University of Delaware).

Precision for iodide based upon triplicate measurements of individual 
samples is within 5-10% in samples greater than 200 nM and within 1-2% 
for iodide concentrations less than 200 nM.  Method precisions in 3.5% 
NaCl were ± 1%.  Precisions for the total methods tend to vary 
significantly from sample to sample and so reported errors "stdev 
Tot_I" reflect the standard deviation of at least three replicates with 
three distinct standard addition curves (n>3).

Spectro_IO3, spectrophotometric concentrations of iodate were 
determined by the spectrophotometric method as modified by Chapman and 
Liss (1977).

EQUIPMENT 
Electrochemical measurements were made in 10 mL glass polarographic 
cells.  EG & G Princeton Applied Research model 384 B polarographic 
analyzers equipped with 303A hanging mercury drop working electrode 
(HDME) stands were used throughout.  Potentials were measured vs. a 
saturated calomel reference electrode (SCE). A platinum counter 
electrode was used for current measurements in a standard three 
electrode voltammetric arrangement.  Iodide gives rise to a peak at a 
potential of -0.306 V, and iodate has a peak potential of -1.08 V.

The concentrations of iodine species were determined by the method of 
standard addition.  A minimum of three standard additions were made for 
each determination. 

Absorbance measurements were obtained at a wavelength of 285 nm using a 
Milton-Roy Spectronic 601 spectrophotometer equipped with 10 cm quartz 
cuvettes. Concentrations were determined based upon comparison with an 
external standard curve generated in 3.5% NaCl solution.


REFERENCES:

Campos, M.L.A. (1997) New approach to evaluating dissolved iodine 
  speciation in natural waters using cathodic stripping voltammetry.
  Marine Chemistry
Chapman, P. and P.S. Liss (1977) The effect of nitrite on the 
  spectrophotometric determination of iodate in seawater. Marine 
  Chemistry 5: 243-249.
Luther, G. W., III, C. Branson Swartz and W.J. Ullman (1988) Direct 
  determination of iodide in seawater by cathodic stripping square 
  wave voltammetry. Analytical Chemistry.  60: 1721-1724.
Luther, G.W., III (1991) Sulfur and iodine speciation in the water 
  column of the Black Sea, in Black Sea Oceanography, E. Izdar and 
  J. W. Murray, Editors.  Kluwer Publishers:  Netherlands. p. 187-
  204.
Herring, J.R. and P.S. Liss (1974) A new method for the determination 
  of iodine species in seawater. Deep-Sea Research I. 21: 777-783.
Truesdale, V.W. and C.P. Spencer (1977) Studies on the determination of 
  inorganic iodine in seawater. Marine Chemistry 2: 33-47


2.6  CTD MEASUREMENTS

A) GANTRY AND WINCH ARRANGEMENTS
   (S. Jordan, R. Phipps, S. Whittle)

MIDSHIPS GANTRY
This gantry is of a novel design, and basically acts in the manner of a 
parallelogram-lifting table.  While the gantry is moving from the 
inboard to outboard positions, the block from which the package is 
suspended describes an arc of a circle; due to the lifting action of the 
gantry, no winch movement is normally necessary while the package is 
being lifted outboard.  Various loads, in our case the CTD package, can 
be safely deployed in virtually any sea state in which the ship can keep 
station.  The performance of the gantry surpassed expectations.  One 
reservation of note concerns the leading of the wire around a number of 
sheaves required to make the wire follow the parallelogram shape of the 
gantry.  On two occasions, during deployment and with the CTD package at 
the sea surface, there became sufficient slack in the wire for it to 
jump off one of the sheaves.


10 TON TRACTION WINCH
The CTD package was deployed using the 10T Traction Winch.  The maximum 
descent/ascent rate required was 60m/min, therefore only one boost and 
two main pumps were required for successful operation (two boost and 
four main pumps being available).  The following problems were noted:-

a) A bearing on the scrolling gear was found to be excessively 
   worn.  This was replaced with a minimal loss of scientific cruise 
   time (25/12/92).  Inspection of the bearing showed it to be 
   incorrectly designed or assembled.
b) The 37kW storage system hydraulic power packs failed to provide 
   power, a fault which persisted after various valves were stripped, 
   cleaned and reassembled (1/1/93).  The fault was eventually traced 
   to an erratically operating potentiometer (by P.Gwilliam and 
   A.Taylor).  Approximately 36 Hours of scientific time was lost.
c) Inboard compensator and back tension adjustments were needed 
   more or less continuously.  Although these were carried out with 
   no loss of scientific time, a satisfactory solution was not found 
   on the cruise.
    
With known limitations the winch worked reasonably well and appears to 
have future expansion potential.  It must be noted that the 
manufacturers intend to modify some of this system during the next ship 
refit, which should eliminate the problems encountered.  The mechanical 
technicians are gaining more knowledge and confidence of the traction 
winch system and are especially pleased to have managed to 
repair/maintain the system with minimal down time.


B) EQUIPMENT, CALIBRATIONS AND STANDARDS
   (T.J.P. Gwilliam)

The CTD equipment used on this cruise was the property of IOS.  The 
following equipment was deployed on the CTD/multi-sampler underwater 
frame:
1. Neil Brown MK. 3 CTD complete with Sensormedics oxygen cell. IOS 
   identification: DEEP01
2. Sea Tech. 100cm folded path transmissometer. Serial No.: 35.
3. General Oceanics 10 liter 24 bottle rosette. Model 1015. IOS 
   identification: 01.
4. Six SIS (Sensoren Instrumente Systeme) digital reversing 
   thermometers and two SIS digital reversing pressure meters.  
   Serial numbers are detailed elsewhere in the report.
5. Simrad Altimeter, Model 807-200M
6. IOSDL 10 kHz. pinger.

Backup equipment consisted of spare CTD, transmissometer, rosette, 
Niskin bottles, pinger and underwater frame.

The shipboard equipment consisted of two complete integral systems for 
demodulating and displaying the CTD data as well as controlling the 
rosette multi-sampler.  Each system included the following major units:-

1. EG&G demodulator.  Model 1401.
2. IBM PS2 PC system with 80Mbyte tape system for archiving the data.
3. EG&G non-data interrupt rosette firing module.  

Calibration of the MK3 CTD temperature and pressure sensors was carried 
out at the IOSDL calibration facility.  Conductivity and oxygen cell 
calibration was carried out at sea by reconciliation with sample values.  
Reversing thermometers were also calibrated in the lab, three at IOSDL 
and four at the Research Vessel Base.

CTD temperature calibration - IOSDL DEEP01 - 19 June 92 was calibrated 
in degrees centigrade in the ITS-90 scale at six temperatures ranging 
from 0.19 to 25.3°.  The transfer standard had been calibrated on 25 
March 92 at the triple points of Mercury and water, and at the melting 
point of Gallium.  The following linear fit for CTD temperature was 
found, with a rms error of 0.4 millidegrees.

                  T = 0.9986622 x Traw  -  0.01282084

No post-cruise laboratory calibration is available at present (March 
1993).  The CTD equipment is required on Discovery for two subsequent 
cruises, and will not be returned to IOSDL until at least June 1993.  
Stability of temperature calibration during the cruise was monitored by 
comparison with reversing thermometers, and this is discussed in the 
description of reversing thermometer data.

CTD pressure calibration - IOSDL DEEP01 - 24 June 92 was calibrated by 
comparison with a Paroscientific Digiquartz model 240 portable transfer 
standard, in series with a deadweight tester; the Digiquartz was used as 
the pressure standard.  The following quadratic fit for CTD pressure was 
found at an ambient temperature of 20°C, with a rms error of 1.8 dbar.

          P = 3.066286E-07 x Praw**2 + 0.9978454 x Praw - 12.6

Further corrections were applied during data processing for variation of 
offset with temperature, and up/down hysteresis.


EQUIPMENT PERFORMANCE

GENERAL
With deployments at approximately four hourly intervals, power to the 
CTD was maintained throughout the cruise to minimize interruption 
problems.  For satisfactory operation the optimum sea cable input 
voltage and current levels were 80 volts at 640 milliamps.  Power 
distribution for the CTD, rosette and altimeter was controlled by a 
simple circuit in a separate 6 inch diameter pressure case mounted on 
the frame.  The sea cable was terminated before sailing and a further 
three times during the cruise when cable damage occurred on deployment 
in heavy swell conditions.  In two of the instances, the slack was 
sufficient to bounce the cable from the winch gantry pulleys, resulting 
in the instrument package free falling through the water for several 
meters.  Approximately 30/40 meters of cable had to be discarded when 
this occurred.


CTD
As usual at the start of a cruise, the oxygen sensor was renewed before 
installing the system into the underwater frame.  The first cast, to 
test the winch and CTD system, highlighted a wiring fault with the 
conductivity electronics which was quickly identified and corrected.  
Before station 12287 (near mid-cruise) the conductivity cell was flushed 
out with 10% hydrochloric acid as data from the previous two stations 
had indicated contamination.


24 BOTTLE ROSETTE SYSTEM.
It was this system that gave the most problems, non-closing of bottles 
and double bottle closing producing a lack operational confidence.  
Cures seemed, at times, to be the result of a "black art" rather than 
engineering expertise.  The pylon was washed down immediately after each 
recovery with hot fresh water and the mechanical switching mechanism 
lubricated with silicon oil before the next deployment.  Several times 
during the cruise the operational rosette pylon (01) was serviced on the 
frame and also interchanged with the backup unit (IOS identification 02) 
for a more detailed mechanical inspection and overhaul.

The present system of codes, indicating bottle-firing information, is 
not satisfactory.  Misfire codes transmitted when one or more bottles 
had in fact closed, multiple trips that could not be identified, and a 
lack of cam position information are just a few of the problems that 
need to be resolved.

In one instance seawater ingress via the camshaft, on pylon 01, caused 
corrosion damage to the 24-way rotary code switch which had to be 
replaced.  Perhaps there would have been greater protection had the 
switch been mounted on the shaft beneath the motor.

Prior to the cruise the springs in all the bottles had been changed for 
ones of a different type at the request of the CFC analysts:  these 
alternative springs had a different length and tension from the 
originals.  Unfortunately, during the cruise the spring fastenings on 
the bottle end caps were mechanically breaking down to such an extent 
that the original springs were restored.  During the cruise, three 
bottles were changed as suspected "leakers".


TRANSMISSOMETER.
The transmissometer worked well throughout most of the cruise, but there 
were times when noise on the data, although not at an unacceptable 
level, proved difficult to trace and eliminate.  The voltage in air was 
4.310 volts, and the blackout offset was 16 millivolts.  Towards the end 
of the cruise a slight leak in the prism pressure balancing mechanism 
was observed, which will require attention back at the laboratory.


SIS THERMOMETERS AND PRESSURE METERS.
Apart from routine battery replacements, one unit, T228, was removed 
after station 12248;  the temperature readings were found to be in error 
by several hundred millidegrees.  Comparison studies with the CTD data 
to check stability and accuracy were carried out and the results are 
shown elsewhere in this report.


ALTIMETER AND 10 KHZ PINGER.
This was the first IOSDL cruise where "depth off bottom" information was 
included into the CTD data stream and digitally displayed on the CTD 
monitor:  the results were very satisfactory.  The unit invariably 
locked onto the bottom from a range of 200 meters and tracked to the 
depth required with no problems.  The 10 kHz.  pinger, working in 
conjunction with the ship's Echosounder had in the past been the only 
way of obtaining this information.  As the cruise progressed, and 
confidence increased with the altimeter, the 10 kHz.  system was used 
more in a backup role.  Apart from requiring battery changes the pingers 
themselves were totally reliable.

SHIPBOARD EQUIPMENT
Overall the deck equipment worked satisfactorily with only one minor 
problem on one of the 1401 deck units.  The acquisition software worked 
well and 12 tapes of 80 Mbytes of backup CTD data were archived.


C) CTD DATA COLLECTION AND PROCESSING (UPDATED JUNE 94)
   (B.A. King)

DATA CAPTURE AND REPORTING
CTD data are passed from the CTD Deck Unit to a small dedicated 
microcomputer ('Level A') where one-second averages of all the raw 
values are assembled.  This process includes checking for pressure jumps 
exceeding 100 raw units (10db for the pressure transducer on the CTD) 
and discarding of spikes detected by a median-sorting routine.  The rate 
of change of temperature is also estimated.  A fuller account of this 
procedure is given by Pollard et al. (1987).  The one-second data are 
passed to a SUN workstation and archived.  Calibration algorithms are 
then applied (as will be described) along with further editing 
procedures.  Partially processed data are archived after various stages 
of processing.  CTD salinity and dissolved oxygen concentrations are 
reconciled with sample values, and any necessary adjustments made.  CTD 
temperatures and pressures are compared with reversing measurements.  
The downcast data are extracted, sorted on pressure and averaged to 2db 
intervals: any gaps in the averaged data are filled by linear 
interpolation.  Information concerning all the CTD stations, is shown in 
the accompanying station list (either at the end of this report or in 
the accompanying .SUM file).  With reference to the stated requirements 
for WHPO data reporting, note in passing:

(a) The number of frames of data averaged into the 2db intervals 
    is not reported.  The IOSDL data processing path does not keep 
    track of this information. 
(b) Approximately half the stations had the 1 db level missing 
    from the averaged 2db files; i.e. the shallowest level was the 3db 
    level. This situation would arise on stations where poor weather 
    did not allow the CTD package to be brought close to the surface 
    for the start of the downcast after the 'soaking' period at 10 
    meters depth. On such stations, the data have been extrapolated to 
    the surface by replicating the T, S and O data from the shallowest 
    available level (usually 3db, occasionally 5db), to provide a 
    complete profile commencing with a 1 decibar data cycle. Such 
    extrapolated data have been assigned a data quality flag of 2.

STATION 12286
In general downcast CTD data are reported. One exception is station 
12286, where upcast data are reported.  The conductivity had a number of 
fouling events on the downcast, identified by a number of jumps of order 
0.002 to low values in the T/S relation.  The upcast data appear to be 
satisfactory.  The sorted, averaged 2db file was therefore compiled from 
the upcast data for all variables.  After this station the conductivity 
cell was cleaned with dilute acid.  After this the quality of the 
salinity data considerably improved, and the required cell offset 
changed by about 0.006 in salinity, suggesting that an accumulation of 
contamination had also been cleared away.


TEMPERATURE CALIBRATION
The following calibration was applied to the CTD temperature data:

                     T = Traw x 0.998662  -  0.01282

This calibration was in degrees C on the ITS-90 scale, which was used 
for all temperature data reported from this cruise.  It was determined 
from a six-point calibration on 19 June 1992.

A post-cruise temperature calibration was determined from a 12-point 
calibration on 8 July 1993 as follows:

                     T = Traw x 0.998559  -  0.01409.

This being sufficiently close to the initial calibration (a change in 
offset of about 1.3 millidegrees during the intervening 12 months), no 
changes were made to the temperature data.

For the purpose of computing derived oceanographic variables, 
temperatures were converted to the 1968 scale, using

                            T68 = 1.00024 T90

as suggested by Saunders (1990). However, all reported temperatures are 
in the ITS-90 scale.

In order to allow for the mismatch between the time constants of the 
temperature and conductivity sensors, the temperatures were corrected 
according to the procedure described in the SCOR WG 51 report (Crease et 
al., 1988).  The time constant used was 0.20 seconds.  Thus a time rate 
of change of temperature (called deltaT) was computed, from 16Hz data in 
the level A, for each one-second data ensemble.  Temperature T was then 
replaced by T + 0.2 x deltaT.


PRESSURE CALIBRATION
The following calibration was applied to the CTD pressure data, based on 
the 24 June 1992 calibration:

          P = Praw **2 x 3.066286E-7  +  Praw x 0.997845  -  9

The calibration applied to the data included an offset different from 
that found in the lab calibration and given in section 2.5b.  The chosen 
offset gave correct pressures on deck and over the top few meters of the 
cast.  A post-cruise pressure calibration at IOSDL on 7 July 1993 
provided a laboratory calibration of

          P = Praw **2 x 4.172168E-7  +  Praw x 0.996952  -  9

which differs from the pre-cruise calibration by less than 2 decibars 
over the range 0-6000. The data from the pre-cruise calibration were 
therefore accepted unchanged.

A further correction was made for the effect of temperature on the CTD 
pressure offset:

                   Pnew= Pold - 0.4 (Tlag - 20)  .

Here Tlag is a lagged temperature, in degrees C, constructed from the 
CTD temperatures.  The time constant for the lagged temperature was 400 
seconds.  Lagged temperature is updated in the following manner.  If T 
is the CTD temperature, tdel the time interval in seconds over which 
Tlag is being updated, and tconst the time constant, then

                   W  =  exp (- tdel/tconst)
     Tlag(t=t0+tdel)  =  W x Tlag(t=t0)  +  (1 - W) x T(t=t0+tdel).

The values of 400 seconds for tconst and the sensitivity of 0.4 db per 
°C are based on laboratory tests.  During the cruise, the variation of 
deck pressure value with ambient temperature was monitored.  A least 
squares linear fit to the set of 73 deck pressure/temperature pairs 
collected had a slope of 0.49 and an offset of 5.4 db at 10°: this 
agrees with the applied correction to within 1.5 dbar over the range 0 
to 20°C.

A final adjustment to pressure is to make a correction to upcast 
pressures for hysteresis in the sensor.  This is calculated on the basis 
of laboratory measurements of the hysteresis.  The hysteresis after a 
cast to 5500m (denoted by dp5500(p)) is given in Table H1a for pressures 
at 500db intervals.  Intermediate values are found by linear 
interpolation.  If the observed pressure lies outside the range defined 
by the table, dp5500(p) is set to zero.  For a cast in which the maximum 
pressure reached is pmax dbar, the correction applied to the upcast CTD 
pressure (pin) is 

       pout = pin - (dp5500 (pin) - ((pin/pmax) * dp5500 (pmax)))

Two thirds of the way through the cruise, at station 12303, a slight 
hysteresis between the up and down theta-S relationship was noted; 
upcast salinity was lower than the down.  The size of the difference was 
small near the bottom of the cast, growing to a maximum of about 0.002 
at about 3000 meters.  At shallower depths the shape of the theta-S 
curve made it impossible to determine differences to the required 
accuracy.  After some consideration, it was felt that the most likely 
cause of this was the CTD pressure (after the above correction for 
hysteresis) still reading slightly too high on the upcast.  Accordingly 
the size of the hysteresis correction was increased, so that upcast 
pressures read slightly lower, and Table H1b was used.


TABLE H1:  (a) Laboratory measurements of hysteresis in pressure sensor dp5500(p) = 
               (upcast - downcast) pressure at various pressures, p, 
               in a simulated 5500m cast.  
           (b) revised form of hysteresis used for stations 12303-12337

	(a)		(b)
p	dp5500(p)	dp5500(p)
db	db		db
5500	0.0		0.0
5000	1.0		0.0
4500	1.2		1.2
4000	1.8		2.8
3500	2.4		4.4
3000	3.0		6.0
2500	3.4		6.8
2000	4.8		6.6
1500	5.6		6.5
1000	6.0		6.4
 500	6.3		6.3
   0	0.0		0.0


EXTRACTION OF UPCAST DATA FOR CALIBRATION
Following procedures developed on previous cruises, CTD data were 
extracted for salinity and oxygen calibration as follows:

The Niskin bottle firing events were logged using a level A 
microprocessor dedicated to that purpose. This provided accurate times 
of the bottle closures.

The CTD data after nominal calibration were averaged into 10-second 
bins, and merged onto the firing events using linear interpolation on 
time; the time for both the CTD data and the firing events were provided 
by the ship's master clock, and were therefore reliable. The 10-second 
averages were believed to be representative of the CTD data for the 
water sampled.

After coefficients for calibration of the CTD oxygen or salinity had 
been calculated and applied to the 1 Hz data, the averaging and merging 
procedure was repeated as often as necessary, until the calibration was 
finalized. In this way, residuals were always calculated between the 
sample values and the latest estimate of the calibrated CTD data.


SALINITY CALIBRATION
Salinity was calibrated during the course of the cruise, by comparison 
with upcast sample salinities.  This was done on a station by station 
basis.  A cell conductivity ratio of 0.996683 was estimated from early 
stations, and this was applied to all station data as an initial 
calibration.  The initial calibration was followed by the correction to 
conductivity ratio:-

           Cnew = Cold x (1  -  6.5E-6 x (T-15) + 1.5E-8 x P)

After reconciliation with sample salinities, vertical profiles of 
residuals showed a systematic depth dependence.  A final salinity 
calibration on a station by station basis was made by fitting the 
residuals with the form

                       a + b * T + c * P.

The need for this procedure is not understood.  We do not necessarily 
believe that this correction represents some physical response of the 
cell to temperature and pressure.  Rather, it is simply a convenient way 
of fitting the salinity residuals with two variables which have 
different variation over the water column; however, since it 
successfully removes most of the systematic part of the salinity 
residuals, it is considered to be a satisfactory tool for the correction 
of the CTD salinity data. The offset at the bottom of each station 
introduced by the expression above, which may be used as a description 
of the drift of the cell, was monitored and varied between -0.008 and 
+0.008 (but not monotonically).  A full list of the coefficients appears 
in Table H4, which is located at the end of this section.

Unlike the oxygen calibration procedure (q.v.), the agreement between 
upcast and downcast T/S profiles was good. It was therefore decided that 
the calibration of upcast CTD salinities by comparison with sample 
salinities would provide adequately calibrated downcast CTD salinity 
data.

Stations 12251-12255: These stations required special attention for 
salinity calibration. An extra temperature sensor (FSI) had been 
introduced on the rosette and interfaced to the CTD for evaluation 
purposes. This extra power demand on the CTD meant that the conductivity 
cell did not return to satisfactory values for some while after firing a 
bottle, while the rosette pylon was recharging. Once the problem had 
been properly identified the power supply to the CTD was increased, and 
the problem solved. In the mean time, however several profiles of data 
were collected for which the upcast salinities were suspect or useless. 
Accordingly, straightforward comparison of upcast CTD salinities with 
sample salinity could not be used for CTD calibration. The CTD data were 
therefore scrutinized to ensure that bad data cycles (sometimes several 
hundred meters worth) were excluded from the calibration. Some salinity 
sample values were not used, if it was not possible to find a suitable 
CTD value for comparison. Sometimes a matching downcast CTD salinity 
would be used, in the manner employed for oxygen calibration. The final 
downcast CTD salinity values are believed to be satisfactory. However, 
there remain a number of sample minus CTD residuals which are quite 
large, mainly associated with poor upcast CTD salinities. The residuals 
for these five stations are therefore omitted entirely from Figure 10.

Station 12325: Two casts were required to complete station 12325. The 
rosette jammed part of the way through the upcast, so no samples were 
collected in the upper 1500 meters of cast 1. A second cast to 1500 
meters was carried out to obtain a complete sample profile (sample 
numbers 32525-32538). The CTD data reported are the downcast of cast 
number 1. Having applied a single CTD salinity calibration to the two 
casts together, the salinity residuals for cast number 2 are rather 
large; basically, the CTD salinities are 0.003 to 0.005 higher than the 
bottle values. Two further pieces of evidence are available: (a) The CTD 
calibration was offset by about 0.002 for station 12326 & 12327 (see 
Table H4). (b) The FSI conductivity cell, described elsewhere, was in 
use on this station. Inspection of the conductivity data from the two 
sensors supports the suggestion that the NBIS salinity data did indeed 
drift to higher values on cast number 2. We therefore conclude that the 
cast 1 downcast salinities which form the cruise data set are 
satisfactory and that the cast 2 upcast CTD salinities, which appear in 
the sample .SEA file, are questionable.


OXYGEN CALIBRATION
CTD oxygens were calibrated by fitting to sample values using the 
following formula:-

O2 = oxsat(T, S) x rho x (oxyc + c) x exp (a x (W x ctdT + (1-W) x oxyT) + b x P)

where the coefficients rho, a, b, the oxyc offset c and the weight W 
were chosen on a station by station basis to minimise the rms residual. 
W is forced to lie in the range 0 to 1.

The fitting of oxygen data at sea did not allow for an offset to the 
oxygen current, and required the weight W to be specified by the user. 
The resulting fits were not entirely satisfactory: rms errors were about 
3-4 µmol/kg, and there was a tendency for the calibrated CTD data to 
produce the wrong oxygen gradient in the deep water.  Introducing the 
time rate of change of oxyc had little effect but, in contrast, an 
offset in oxyc (of the order of -0.07 µA) produced a significant 
improvement.  IOSDL has not previously found it necessary to introduce 
an offset in oxyc in order to achieve satisfactory oxygen fits, and the 
value required is rather greater than suggested in the WOCE Manual of 
operations and methods.  With hindsight, we suspect that this offset 
indicates an unusual oxygen cell, which should probably have been 
replaced.  However, having introduced the offset, there is no reason to 
doubt the quality of the derived CTD oxygen data.  Table H5, located at 
the end of the section, gives oxygen fitting coefficients and residuals 
station by station.  For a few stations, where there were insufficient 
sample values to fit all five coefficients sensibly, b and/or c were 
chosen from values on nearby stations.

For some stations, several passes through the fitting procedure were 
used to arrive at the final coefficients.  After an initial fit, 
outliers were identified, and excluded from subsequent fits.  In this 
way the CTD data were used to help identify sample values requiring 
'suspect' or 'bad' flags.  There is further discussion of this in the 
section describing the oxygen sample data.  In general, samples believed 
to be suspect for any reason, were excluded from the CTD fitting.  
However, it was sometimes necessary to include them (stations 12253 to 
12257, for example, where all samples were suspect), and such included 
samples are listed in the sample oxygen discussion.  Furthermore some 
'good' samples could not be fitted properly with the CTD data - 
typically in regions of strong vertical gradient.  These samples were 
also excluded from the fit if their exclusion resulted in significantly 
improved residuals over the rest of the profile.  Numbers of samples 
excluded for this reason are also listed elsewhere.

The residuals between CTD and sample oxygens are summarized in a table 
in Section 2.2, where they are averaged into 500 meter depth bins. The 
errors appear to have a systematic form. However, the rms difference of 
all samples is 2.66 µmol/kg, and 1.73 µmol/kg for samples from deeper 
than 3000 dbar. We therefore consider the CTD data to be acceptable in 
their present form.

Calibration of downcast CTD oxygen data using upcast samples: The 
calibration algorithm for the CTD oxygen data generally produced up and 
down profiles which did not match particularly well, either as 
pressure/oxygen profiles or as potemp/oxygen profiles. This is believed 
to be a widespread problem, arising from the calibration algorithm not 
being a sufficiently good model of the true response of the sensor. 
However, we know that some investigators find that they can get 
consistently good up/down matching. Whether this varies from cell to 
cell, is a subtle function of the electronics of the CTD, or a function 
of the way the algorithm is applied, we do not know. In the present 
data, up/down agreement varied from very good to appalling, with no 
apparent reason or change of procedure. The fact remains, therefore, 
that we require to bring the downcast CTD oxygens (which we report for 
all but station 12286) into agreement with the upcast samples. For each 
sample, we thus need to extract a downcast CTD data cycle (press, temp, 
oxyc, oxyt) for calibration against sample oxygen. Again following 
procedures developed on previous cruises, we extracted a downcast data 
cycle of CTD data as follows:

a) the pressure, potential temperature and potential density 
   (referenced to the nearest round multiple of 500db) at the bottle 
   closing time were extracted. This provided a choice of three 
   parameters which could be used to find a suitable matching 
   downcast data cycle. No one parameter was considered to be 
   universally the best. Matching on pressure was not considered to 
   be ideal, because of vertical motion of water during the elapsed 
   time between down and up cast passing through the same water mass. 
   In general, because of up/down salinity biases on some stations, 
   potential temperature (supposed conserved while internal waves 
   pass through) would seem to be the best, and preferable to 
   potential density. However, the profiles encountered on this 
   cruise included ones where, because of the salinity gradient, 
   there were reversals in potential temperature, or regions of very 
   weak potential temperature gradient. In these cases, potential 
   temperature was not suitable for matching, and potential density 
   was used. Potential density could not be used throughout, however, 
   because apart from vulnerability to poor salinity values there 
   were also regions where potential temperature and salinity had 
   reasonable gradients but potential density had only very weak 
   gradients. The matching procedure therefore usually employed 
   potential temperature at pressures greater than 3000db, and 
   potential density at pressures less than 3000db. Matched data 
   cycles where the up/down pressure difference was greater than 10% 
   were flagged and received special attention.
b) the CTD downcast was scanned for pairs of data cycles which 
   bracketed the chosen parameter, and closer of the pair listed.
c) where step (b) produced more than one candidate data cycle 
   (arising from potemp reversals, for instance), the one with the 
   nearest pressure was chosen.
d) thus far, the procedure was entirely automated. Every matching 
   data cycle was then examined for plausibility, by (subjective) 
   consideration of agreement of pressure, temperature and salinity 
   between up and down data cycles. If agreement was poor, or if the 
   automatic procedure (ie choose the one with the nearest pressure 
   from two or more possibles ) had apparently chosen the wrong data 
   cycle, a different data cycle was specified to be the matching 
   one. This quite commonly occurred for the shallowest sample, when 
   the data cycle with matching pressure might be specified instead.
e) the CTD values from the resulting set of up to 24 downcast data 
   cycles were employed in the oxygen fitting algorithm. 

Conversion from µmol/l to µmol/kg: Because of the sequence of events, 
and the careful thought that went into the conversion of oxygen units, 
the CTD oxygen data were fitted to sample data measured in µmol/l, that 
had not yet been converted to µmol/kg. Accordingly the CTD data also 
require conversion.  Since the requirement is for the converted CTD data 
to fit the converted sample data, the CTD data throughout the cruise 
have been scaled using density calculated as for the sample data (see 
the discussion of sample oxygens), namely one calculated from measured 
salinity and a temperature which is a piecewise linear function of 
measured potential temperature.


TRANSMISSOMETER DATA
Transmittance data from 1 one meter folded path transmissometer were 
routinely collected throughout the cruise.  At present (June 1994) 
station to station inconsistencies in the calibration of these data mean 
that they are not ready for submission to the WHPO with the bulk of the 
CTD data.  They will be submitted in due course, after completing best 
efforts at their calibration.

SIS THERMOMETER DATA, AND THE STABILITY OF THE CTD TEMPERATURE SENSOR
Six SIS digital temperature meters and two digital pressure meters were 
used throughout the cruise.  These, along with salinity and chemical 
data from the rosette water samples, were used to determine the depth of 
bottle firings.


DIGITAL REVERSING TEMPERATURE METERS (RTM)
The digital temperature meters were calibrated using the linear fits 
given in Table H2.  In addition to these another sensor, T228, was 
discarded after the first station of the A11 cruise.

A comparison of CTD and RTM temperatures is given in Table H3 below.  
The table has four parts.  Parts (a) and (b) present data from the 
entire section, with part (b) for temperature colder than 2°; as 
expected, the latter have generally smaller standard deviations.  Parts 
(c) and (d) show the data colder than 2° further subdivided about 
station 12293, which is one of the stations over the mid-Atlantic Ridge.  
Three numbers of observations are given in each part, corresponding to 
the number of differences greater than 10 millidegrees, considered as 
outliers and discarded, the number less than 10 millidegrees, from which 
mean and standard deviation are calculated, and the number within two 
standard deviations of the mean.

The most significant feature of these tables is the change in mean value 
of ctd-T399 and ctd-T400 between the two halves of the cruise, the mean 
difference changing by 1.3 millidegrees.  This is rather more than the 
standard deviation of the measurement, and much more than the standard 
error of the estimate of the mean for each group.  Although this might 
be thought to indicate an offset in CTD temperature calibration (there 
being no change in the T400-T399 difference), there is no evidence for 
this in the ctd-T401 and ctd-T219 pairs.  Our tentative conclusion is 
that the difference arises because the temperature observed at rosette 
position 1 is generally warmer in the eastern basin than in the western 
basin.  Note the mean temperature of the observations, which is shown in 
the last column of Table H3 (c) and (d).  We suppose that non-linearity 
in the response of either CTD or RTM temperature near zero may be the 
cause of the change in CTD-RTM difference.  If it is the behavior of the 
RTM thermometers that is nonlinear, then it must be very similar in the 
two thermometers; this is not unreasonable for two instruments of the 
same type.  On the other hand, we do not exclude the possibility of 
nonlinear behavior in the CTD temperature.  When the CTD is re-
calibrated on return to IOSDL, careful attention will be paid to 
establishing the linearity or otherwise of the calibration near zero.  
(Note added, May 1994: This effect was examined by careful calibration 
of the CTD near zero degrees in late 1993. Although some other CTD 
instruments have been found by IOSDL to have nonlinear errors of several 
millidegrees, the instrument used during A11 had errors of no more than 
0.5 millidegrees, and then only within 0.2 degrees of zero. CTD non-
linearity near zero is therefore unable to account for the observed 
change in CTD-RTM difference.)  In any case the overall consistency of 
the CTD and RTM comparisons and the magnitude of the change in 
differences amongst them strongly imply that there was no significant 
change in the CTD calibration between the start and the end of the 
cruise.


DIGITAL REVERSING PRESSURE METERS (RPM)
Two reversing pressure meters were used:

Rosette		Pressure
position	meter
1		P6132H
8		P6075S

Despite the shortcomings in the RPM performances, which are described 
below, their data were very useful in confirming or identifying the 
depth of bottle closures.

Calibration of P6075S were carried out by the manufacturer on both 
13.2.88 and 27 3 90 the latter at temperatures of both 3 and 20°C.  
These indicated that corrections of between -7 and +3 dbar were required 
over the range 0 to 5400 dbar.  However residuals between the calibrated 
RPM and the CTD were found on cruise 199 to exceed 30 dbar at pressures 
greater than 3000 dbar.

P6132H was calibrated by the manufacturer on 22.2.90.  Linear 
interpolation was used to correct the RPM between the following 
calibration values in dbars:

(P6132H pressure, correction applied), (0006,-6), (0975,+6), 
(1949,+12), (2930,+12), (3915,+8), (4907,-4), (5405,-11), (6022,-22).

The last pair was not supplied by the manufacturer, but was an 
extrapolation of the manufacturer's information.  In general, after 
applying the above calibration, P6132H shows a consistent offset 
compared with the CTD of about 14 dbars over the range 1800 - 6000 dbar.

Discrepancies of similar magnitude between RPM and CTD pressures have 
been noted on a number of previous IOS cruises, see for example the 
CONVEX cruise report (Gould et al, 1992).  On cruise 199 the CTD bottom 
pressures were converted to depth and were compared with corrected 
Echosounder depths minus depth of CTD off bottom: the differences had a 
mean value of 3 meters and 75 percent were smaller than 12 meters.  On 
the CONVEX cruise an even smaller mean for nearly 100 stations was 
found.  We are therefore quite confident of the CTD pressure calibration 
and in the near future plan to carry out calibration and other tests of 
the RPM instruments at IOSDL.


REFERENCES

CREASE, J. et al. 1988 The acquisition, calibration and analysis of CTD 
  data. Unesco Technical Papers in Marine Science, No 54, 96pp.
GOULD, W.J. et al. 1992 RRS Charles Darwin Cruise 62, 01 Aug-04 Sep 
  1991.  CONVEX-WOCE Control Volume AR12.  IOSDL, Institute of 
  Oceanographic Sciences Deacon Laboratory Cruise Report, No 230, 60pp.
POLLARD, R.T., READ, J.F. and SMITHERS, J. 1987 CTD sections across the 
  southwest Indian Ocean and Antarctic Circumpolar Current in southern 
  summer 1986/7.Institute of Oceanographic Sciences Deacon Laboratory 
  Report No 243, 161pp.
SAUNDERS, P.M. 1990 The International Temperature Scale 1990, ITS-90.  
  WOCE  Newsletter No 10, p10.  (Unpublished manuscript).


TABLE H2: Digital RTM calibrations.  Tcal = b x Traw + a

Position	Thermometer	b	a	   Date off	Source
on rosette					   calibration
 1		T399		1.00031	-0.00331   20/7/92	IOSDL
 1		T400		1.00006	 0.00146   20/7/92	IOSDL
 4		T401		1.00016	-0.01002   20/7/92	IOSDL
 4		T219		0.99992	-0.01250   18/8/92	RVS
 8		T238		0.99992	 0.00175   18/8/92	RVS
12		T220		0.99999	-0.00570   18/8/92	RVS


TABLE H3: Summary of RTM data

(a)							(b)
All Data						T < 2°
Pair		n	n	n	mean	sd	n	n	n	mean	sd
		>10	<10	<2sd	mdeg	mdeg	>10	<10	<2sd	mdeg	mdeg
		mdeg	mdeg				mdeg	mdeg
 ctd-T399	1	92	90	 1.0	1.6	0	75	72	 1.1	1.5
 ctd-T400	2	91	88	 0.8	1.3	1	74	70	 0.9	1.1
 ctd-T401	3	90	84	 2.1	2.2	2	60	56	 2.0	1.7
 ctd-T219	5	82	76	-6.7	2.3	2	56	52	-6.8	1.7
 ctd-T238	9	80	75	 1.6	2.5	0	17	16	 0.7	3.0
 ctd-T220	9	69	65	 2.0	2.6	0	 1	 1	 1.9	 -
T400-T399	0	93	89	 0.4	0.9	0	75	72	 0.4	0.9
T401-T219	4	82	79	-8.7	1.8	2	56	55	-8.6	1.4

(c)							(d)
stnnbr < 12293						stnnbr > 12293
Pair		n	n	n	mean	sd	mean	n	n	n	mean	sd	mean
		>10	<10	<2sd	mdeg	mdeg	temp	>10	<10	<2sd	mdeg	mdeg	temp
		mdeg	temp				degC	mdeg	temp				degC
 ctd-T399	0	38	36	 0.6	0.9	0.33	0	36	35	 1.9	0.8	1.19
 ctd-T400	0	38	37	 0.3	1.0	0.33	0	36	35	 1.6	0.9	1.19
 ctd-T401	1	39	37	 2.0	1.5	0.60	1	20	19	 2.2	1.8	1.46
 ctd-T219	0	36	34	-6.8	1.7	0.48	2	19	18	-6.6	1.5	1.46
T400-T399	0	38	36	 0.3	0.9	0.33	0	36	34	 0.3	0.5	1.19
T401-T219	0	36	35	-8.9	1.5	0.48	2	19	18	-8.9	1.1	1.46


TABLE H4:  Final CTD salinity adjustments. S = S + (a + b * T + c * P)/1000
           The number in the deep offset column was the offset applied to the CTD 
           salinities at the bottom of the cast as a result of the residual 
           fitting procedure.

Station	  a	 b	 c		Deep	Comments
number					offset
12247	 -4.95	 0.19	-0.00597	-0.0054
12248	 -2.80	 0.00	 0.00000	-0.0028
12249	 -2.00	 0.00	 0.00000	-0.0020
12250	 -2.00	 0.00	 0.00000	-0.0020
12251	 -2.00	 0.00	 0.00000	-0.0020
12252	 -1.87	 0.09	-0.00141	-0.0054
12253	 -7.09	 0.38	 0.00128	-0.0025
12254	 -4.00	 0.00	 0.00000	-0.0040
12255	 -2.35	-0.15	 0.00002	-0.0023
12256	 -2.20	 0.11	-0.00058	-0.0050
12257	  1.58	 0.10	 0.00000	 0.0016
12258	 -1.34	 0.50	 0.00015	-0.0004
12259	  3.35	-0.27	-0.00031	 0.0015
12260	  3.50	 0.00	 0.00000	 0.0035
12261	  3.86	-0.62	-0.00030	 0.0018
12262	  0.04	 0.28	 0.00034	 0.0022
12263	  3.60	-0.21	-0.00005	 0.0032
12264	  4.70	-0.64	-0.00069	 0.0006
12265	  3.90	-0.17	-0.00020	 0.0028
12266	  2.90	 0.00	-0.00013	 0.0022
12267	  3.80	-0.37	-0.00029	 0.0022
12268	  5.30	-0.25	-0.00045	 0.0029
12269	  7.60	-0.78	-0.00151	-0.0004
12270	  2.40	 0.00	 0.00000	 0.0024
12271	  2.60	 0.02	-0.00029	 0.0011
12272	  0.50	 0.18	 0.00052	 0.0031
12273	  3.30	 0.04	-0.00030	 0.0018
12274	  1.10	 0.16	-0.00032	-0.0005
12275	  2.10	-0.12	-0.00048	-0.0003
12276	 -1.50	 0.35	 0.00014	-0.0007
12277	  0.10	 0.02	-0.00004	-0.0001
12278	  1.00	 0.13	-0.00035	-0.0009
12279	  4.80	-0.30	-0.00068	 0.0011
12280	 -0.60	 0.30	-0.00032	-0.0022
12281	  2.00	-0.10	-0.00048	-0.0005
12282	  4.10	 0.16	-0.00012	 0.0035
12283	  0.20	 0.13	-0.00048	-0.0023
12284	  0.80	 0.06	-0.00018	-0.0001
12285	  6.40	 0.27	 0.00029	 0.0078
12286	  4.90	-0.37	-0.00048	 0.0026
12287	 -0.80	-0.45	-0.00063	-0.0040	Note 1
12288	 -3.60	 0.11	-0.00027	-0.0048
12289	 -8.00	 0.58	 0.00072	-0.0045
12290	 -3.60	-0.03	-0.00038	-0.0052
12291	 -2.20	-0.01	-0.00064	-0.0051
12292	 -0.90	-0.25	-0.00086	-0.0046
12293	 -0.50	-0.27	-0.00091	-0.0041
12294	 -6.89	 0.39	 0.00057	-0.0044
12295	 -8.45	 0.55	 0.00102	-0.0042
12296	 -1.02	-0.40	-0.00120	-0.0059
12297	 -5.67	 0.05	 0.00012	-0.0052
12298	 -6.96	 0.31	 0.00045	-0.0052
12299	 -4.61	 0.01	 0.00029	-0.0036
12300	  1.24	-0.39	-0.00039	-0.0008
12301	  1.53	 0.07	-0.00056	-0.0005
12302	  1.62	 0.21	-0.00063	-0.0006
12303	  1.90	-0.32	-0.00084	-0.0018
12304	  3.35	-0.43	-0.00096	-0.0009
12305	 -0.04	 0.04	-0.00024	-0.0010
12306	  0.99	-0.18	-0.00047	-0.0010
12307	 -0.63	-0.02	-0.00011	-0.0011
12308	  2.03	-0.24	-0.00083	-0.0014
12309	  1.37	-0.22	-0.00031	-0.0001
12310	 -2.34	 0.09	-0.00023	-0.0033
12311	 -0.51	-0.03	-0.00031	-0.0020
12312	 -0.03	-0.06	-0.00016	-0.0008
12313	  1.24	-0.14	-0.00011	 0.0005
12314	  0.79	-0.05	-0.00031	-0.0008
12315	  0.99	-0.13	-0.00045	-0.0015
12316	 -0.55	 0.11	-0.00032	-0.0021
12317	 -1.64	 0.03	-0.00072	-0.0053
12318	 -1.07	-0.11	-0.00108	-0.0068
12319	 -2.59	-0.09	-0.00064	-0.0061
12320	 -1.56	-0.06	-0.00069	-0.0053
12321	 -2.92	 0.31	-0.00050	-0.0052
12322	 -2.06	-0.27	-0.00058	-0.0055
12323	 -2.90	-0.10	-0.00041	-0.0052
12324	 -2.18	 0.00	-0.00067	-0.0056
12325	 -2.64	-0.09	-0.00062	-0.0059
12326	 -5.69	 0.05	-0.00036	-0.0075
12327	-12.42	 0.36	 0.00659	-0.0078
12328	-11.91	 0.36	 0.01548	-0.0025
12329	 -7.69	 0.40	 0.00176	-0.0046
12330	 -3.45	 0.10	 0.00079	-0.0020
12331	 -2.96	 0.12	 0.00048	-0.0016
12332	 -1.92	 0.01	-0.00017	-0.0023
12333	 -0.83	-0.05	-0.00057	-0.0027
12334	  0.66	-0.13	-0.00110	-0.0035
12335	 -1.58	-0.17	-0.00083	-0.0052
12336	 -1.37	-0.03	-0.00033	-0.0029
12337	  1.62	-0.20	-0.00080	-0.0025

Notes
1) The conductivity cell was cleaned prior to station 12287 with dilute acid.


TABLE H5: CTD oxygen fitting coefficients and residuals
          O2 = oxsat(T,S) * rho * (oxyc + c) * exp(a * (W*ctdT + (1-W)*oxyT) + b*P)

Station	rho	a	  b		c	  W		rms	No. of
number							      residual samples
							      µmol/kg	in fit
12247	1.3509	-0.04531  0.0002200*	-0.0500*  0.5232	 4.50	 5
12248	1.4430	-0.04985  0.0002200*	-0.0500*  0.3548	 5.81	 8
12249	1.5021	-0.05487  0.0001365	-0.0500*  0.4718	 2.54	10
12250	1.3023	-0.04065  0.0002307	-0.0500*  0.4500*	10.31	10
12251	1.3957	-0.04580  0.0002102	-0.0564	  0.4625	 0.97	 9
12252	1.3773	-0.04171  0.0001875	-0.0364	  0.3563	 3.75	18
12253	1.3662	-0.03939  0.0002661	-0.0798	  0.5888	 4.87	15
12254	1.4825	-0.04791  0.0002278	-0.0792	  0.5610	 5.06	14
12255	1.4115	-0.04461  0.0001792	-0.0342	  0.4481	 4.16	19
12256	1.5397	-0.03968  0.0002144	-0.0799	  0.0288	 4.60	22
12257	1.5118	-0.05284  0.0003048	-0.1309	  0.4454	 3.40	20
12258	1.3285	-0.03882  0.0001408	 0.0145	  0.4457	 2.53	23
12259	1.4914	-0.03994  0.0002219	-0.0783	  0.2443	 3.49	21
12260	1.4591	-0.04499  0.0001978	-0.0549	  0.6260	 2.68	12
12261	1.5485	-0.04432  0.0002515	-0.1069	  0.4804	 3.57	24
12262	1.5619	-0.04913  0.0002569	-0.1128	  0.3995	 3.98	23
12263	1.2720	-0.03901  0.0001499	-0.0179	  0.5207	 3.92	24
12264	1.4108	-0.04008  0.0002459	-0.1271	  0.3886	 3.52	23
12265	1.3179	-0.03916  0.0002020	-0.0811	  0.4963	 3.38	23
12266	1.3719	-0.03900  0.0002317	-0.1109	  0.4432	 2.07	22
12267	1.3776	-0.03755  0.0002525	-0.1244	  0.5492	 1.55	17
12268	1.3353	-0.03949  0.0002305	-0.1048	  0.6906	 2.30	23
12269	1.3596	-0.04107  0.0002267	-0.1036	  0.5512	 1.32	16
12270	1.2812	-0.03574  0.0002142	-0.0823	  0.4933	 1.96	15
12271	1.3696	-0.03904  0.0002298	-0.1067	  0.6887	 3.02	24
12272	1.3317	-0.03626  0.0002229	-0.0944	  0.8601	 2.89	20
12273	1.3189	-0.03277  0.0002282	-0.1049	  0.4223	 2.87	21
12274	1.3318	-0.03581  0.0002334	-0.1088	  0.4931	 2.27	23
12275	1.2802	-0.03730  0.0002004	-0.0718	  0.6542	 3.22	23
12276	1.3504	-0.04087  0.0002080	-0.0862	  0.8183	 4.58	23
12277	1.3447	-0.03611  0.0002030	-0.0817	  0.4094	 1.90	35
12278	1.3839	-0.03719  0.0002150	-0.0940	  0.4477	 2.11	24
12279	1.3907	-0.04412  0.0002012	-0.0813	  0.7213	 3.04	22
12280	1.3703	-0.04452  0.0002014	-0.0771	  0.6437	 2.57	24
12281	1.3132	-0.03819  0.0001860	-0.0599	  0.4888	 3.25	22
12282	1.3118	-0.03885  0.0001818	-0.0516	  0.8816	 3.88	23
12283	1.3900	-0.04221  0.0002096	-0.0952	  0.5435	 2.68	23
12284	1.4284	-0.04711  0.0001855	-0.0750	  0.8929	 3.56	22
12285	1.3718	-0.04497  0.0002173	-0.1035	  0.4343	 2.74	22
12286	1.4744	-0.05322  0.0001871	-0.0730	  0.0000	 2.33	21
12287	1.2674	-0.03658  0.0001526	-0.0035	  0.6970	 1.88	23
12288	1.3757	-0.04111  0.0001603	-0.0315	  0.5249	 3.25	21
12289	1.4411	-0.04461  0.0001840	-0.0607	  0.4252	 2.29	21
12290	1.3827	-0.04342  0.0001806	-0.0481	  0.6347	 3.20	20
12291	1.4099	-0.04423  0.0001728	-0.0461	  0.6092	 2.39	22
12292	1.3167	-0.03853  0.0001678	-0.0255	  0.7202	 1.91	19
12293	1.3517	-0.03807  0.0001819	-0.0454	  0.5418	 3.33	22
12294	1.2880	-0.03851  0.0002598	-0.1160	  0.8752	 2.95	20
12295	1.4685	-0.04358  0.0002230	-0.0930	  0.6440	 4.69	19
12296	1.3764	-0.03828  0.0002070	-0.0653	  0.6122	 1.76	21
12297	1.4189	-0.04084  0.0002023	-0.0662	  0.4213	 1.35	17
12298	1.3558	-0.04550  0.0001894	-0.0379	  0.8781	 3.33	17
12299	1.4762	-0.05084  0.0001891	-0.0593	  0.6076	 4.23	17
12300	1.3929	-0.04131  0.0001923	-0.0554	  0.7530	 3.63	19
12301	1.3777	-0.03845  0.0001937	-0.0532	  0.4853	 1.93	18
12302	1.2843	-0.03212  0.0001847	-0.0310	  0.4087	 1.52	16
12303	1.3022	-0.03259  0.0001876	-0.0385	  0.4467	 2.01	19
12304	1.3744	-0.03734  0.0001998	-0.0604	  0.5594	 2.55	19
12305	1.2735	-0.03122  0.0001826	-0.0271	  0.4398	 2.59	19
12306	1.2605	-0.03233  0.0001727	-0.0158	  0.4381	 3.27	14
12307	1.3993	-0.03702  0.0001913	-0.0598	  0.4224	 2.63	18
12308	1.3340	-0.03127  0.0001973	-0.0548	  0.1266	 2.75	19
12309	1.3658	-0.03775  0.0001957	-0.0576	  0.6492	 2.40	19
12310	1.3309	-0.03648  0.0002067	-0.0774	  0.3781	 2.64	22
12311	1.4089	-0.03736  0.0002030	-0.0756	  0.2534	 2.04	22
12312	1.3595	-0.03842  0.0002131	-0.0828	  0.5908	 1.22	22
12313	1.4339	-0.03848  0.0002101	-0.0861	  0.4055	 2.40	23
12314	1.3870	-0.03763  0.0001923	-0.0628	  0.5510	 2.40	22
12315	1.4477	-0.04060  0.0002107	-0.0863	  0.6599	 2.24	23
12316	1.4004	-0.03675  0.0001983	-0.0709	  0.3691	 2.63	22
12317	1.3552	-0.03659  0.0002223	-0.0919	  0.5974	 2.50	22
12318	1.4037	-0.03577  0.0002085	-0.0817	  0.2703	 2.46	23
12319	1.3553	-0.03552  0.0002037	-0.0761	  0.4580	 2.49	24
12320	1.3557	-0.03484  0.0002043	-0.0762	  0.3342	 3.41	23
12321	1.3599	-0.03461  0.0001987	-0.0719	  0.2483	 1.95	21
12322	1.3645	-0.03356  0.0001958	-0.0723	  0.1471	 2.48	24
12323	1.3633	-0.03291  0.0001991	-0.0754	  0.0926	 2.95	23
12324	1.3647	-0.03653  0.0002016	-0.0756	  0.4403	 3.43	22
12325	1.3672	-0.03429  0.0001998	-0.0745	  0.4250	 3.41	22
12326	1.3245	-0.03249  0.0002033	-0.0732	  0.2570	 3.19	22
12327	1.2291	-0.03339  0.0001850	 0.0055	  0.2482	 2.73	 6
12328	1.2354	-0.03276  0.0002498	-0.0500*  0.6402	 3.91	 9
12329	1.1587	-0.02998  0.0002850	-0.0500*  0.8344	 3.39	12
12330	1.2193	-0.03124  0.0003188	-0.0879	  0.6940	 3.60	12
12331	1.2067	-0.03070  0.0002420	-0.0538	  0.5210	 1.76	14
12332	1.2640	-0.03385  0.0002108	-0.0500*  0.5344	 2.03	14
12333	1.3681	-0.03430  0.0002046	-0.0730	  0.1478	 2.33	17
12334	1.2027	-0.02930  0.0001942	-0.0238	  0.2846	 3.34	18
12335	1.3430	-0.03520  0.0002112	-0.0754	  0.3253	 4.67	21
12336	1.3180	-0.03468  0.0002247	-0.0888	  0.3926	 4.09	22
12337	1.3640	-0.03421  0.0002080	-0.0771	  0.3187	 3.31	21

Notes
1) Coefficients marked with an asterisk (*) were specified rather than fitted.
2) The rms residual is found from the sum of the squared residuals, divided by   
   the number of samples used in the fit minus the number of fitted coefficients.


2.7  XBTs
     (S.R. Thompson)

XBT profiles during Discovery cruise 199 were collected using the Bathy 
Systems Inc.  XBT program version 1.1 and SA-810 XBT controller, with 
the probes launched from a Sippican Corporation hand-held launcher.  The 
inflection points calculated by the program were transmitted to the GTS 
network after each launch via the GOES satellite.  ASCII versions of the 
raw data were transferred to the RVS level A using a diskette.

An inter-comparison was carried out by comparing profiles made in a 
marked mixed layer with the surface temperature measured on the 
thermosalinograph in regions of low horizontal temperature gradient.  
Linear regression of TSG onto XBT temperature gave a slope of 0.99 and 
an uncertainty of 0.01, with an offset of 0.2° at 10°C.

Launch 107 was a calibration run using the test probe.  This yielded 
14.85° for a resistor chosen to give a value of 15.0.
Two problems were noted with the software:

  1) The bucket temperature information in the header does not appear 
     to be saved.  This means that if a file is not transmitted to the 
     satellite immediately after the launch then the temperature must 
     be re-entered in the header.
  2) The column indicating whether the file has been transmitted 
     sometimes fails to show a 'Y' after transmission.
     Information concerning all the successful launches is shown in the 
     accompanying XBT station list (end of the report).  All launches 
     were T7 probes unless marked otherwise and breaks in the launch 
     numbers indicate probe failures, of which there were nine (eight 
     T7 and one T5).  Launches 101 to 125 did not form part of the A11 
     section


2.8  ACOUSTIC DOPPLER CURRENT PROFILER (ADCP)
     (P.M. Saunders and R. Marsh) 

The instrument used was a RDI 150 kHz unit, hull-mounted approximately 
2m to port of the keel of the ship and approximately 33m aft of the bow 
at the waterline.  On this cruise the firmware version was 17.10 and the 
data acquisition software was 2.48.  For most of its operation the 
instrument was used in the water-tracking mode, recording 2 minute 
averaged data in 64 x 8m bins from 8m to 512m.  On the shelf at the 
start and end of the cruise, the instrument was put into a mode in which 
both water and the bottom are tracked.  Here 2 minute averaged data was 
collected in 50 x 4m bins from 6m to 200 m depth.

The performance of the instrument was excellent throughout the cruise: 
on station, profiles were almost always recorded to 300m depth, and 
whilst steaming, except in the heaviest weather, profiles in excess of 
200m were the norm.  Data were passed in real time from the deck unit to 
a SUN workstation acquisition area:  once a day, 24 hours of the data 
were read into the processing area.

Our processing has much in common with that of Griffiths (1992) except 
in one or two important respects, but for completeness will be outlined 
here.  Stage 0 was to capture the 24 hours of data and write it into an 
appropriate format.  Stage 1 consisted of correcting the time base for 
instrument clock drift and changing the time stamp from end of data 
period to center of data period.  Stage 2 consisted of applying 
misalignment corrections (to be described below), averaging data into 10 
minute periods, merging with the ship's motion over the earth from GPS 
navigation and thereby deriving, by algebraic addition, current 
components averaged over the same interval.  At this stage error 
velocities were displayed as time series to identify both depths of good 
data and periods of poor data: there were remarkably few of the latter.

Stages 3 and 4 of the processing were novel: average profiles were 
constructed in approximate 4 hour chunks whose boundaries were selected 
by inspection and corresponded to 'on station' and 'steaming' 
activities.  Data for maneuvering periods were excluded.  The average 
profiles were identified by the station number, with the addition of the 
letter A to indicate the steaming period after the station.  A cruise 
data set was constructed by appending the files together and we expect 
to employ this modest body of data in a combined analysis with the 
hydrographic data.  For more detailed studies of the Ekman layer, for 
example, and the response of the upper ocean to storm force winds, the 
10 minute data set will be utilized.

As is well known, a key element in the determination of currents (water 
motion over the Earth's surface) from the ADCP is the ship's gyro.  This 
allows the fore and aft and athwartships components of flow determined 
from the RDI instrument to be resolved into east and north components 
and so added to the ship's motion determined by navigation (GPS).  The 
results are sensitive to gyro error, gyro drift, and the alignment of 
the transducers on the hull.  In order to evaluate these errors, zigzag 
calibration exercises (Pollard and Read, 1989) were carried out on 4 
occasions:- 24 December (courses 0°, 090°), 8 January (courses 045°, 
135°), 21 January (courses 015°, 105°), and 31 January (courses 015°, 
105°).  The results from the first 3 calibration exercises showed a 
small increase in the misalignment angle from 0.5° to 1.0° to the right 
of the apparent gyro direction.  On board the initial value of 0.55° was 
used in the preliminary analysis of the data.  Ashore considerable post 
processing will be undertaken to correct for both directional and gyro 
errors (see the section 2.9c).


REFERENCES

GRIFFITHS, G.1992.  Handbook for VM-ADCP-PSTAR system as used on RRS 
  Charles Darwin and RRS Discovery. James Rennell Centre for Ocean 
  Circulation Internal document No.4, 24pp.  
POLLARD, R.T. and J.F.READ, 1989.  A method for calibrating ship-mounted 
  acoustic doppler profiles and the limitation of gyro compasses. 
  Journal of Atmospheric and Oceanic Technology, 6, 859-865.


2.9  NAVIGATION

A) GPS-TRIMBLE
   (P.M. Saunders and M.G. Beney)

Navigation, i.e. ship position and velocity over the ground, was 
provided throughout the cruise by a Trimble GPS receiver.  No rubidium 
clock was available so at least 3 satellites were required for a fix.  
The observations are interfaced via a level A microprocessor (see 
section 2.11 on computing) into the SUN acquisition system.  In order to 
prevent hanging or crashing of the level A, which was of new design, the 
sample rate was set to 0 and data was logged at approximately 1 Hz.  
Editing of this data was carried out to exclude a small but tiresome 
number of zero times, zero latitudes, zero longitudes, northern 
hemisphere positions (!) or otherwise suspect data and sub-sampled at 30 
second intervals.  This data known as 'gps' was archived and provided 
coverage for approximately 95 % of the cruise.

In order to complete the navigation data set for 100 % of the time, 
during periods of absent or inaccurate GPS fixes the ship's gyro and 
Emlog data were combined to give a dead reckoning position.  Such data 
is flagged and the data is known as 'bestnav'.  Transit satellite data 
were not used on the cruise.

Positions were logged in port at the start of the cruise and a rms 
position error of approximately 30 m was found.  Evidently selective 
availability was in operation at this time.  Underway errors are known 
to be larger.


B) ELECTROMAGNETIC LOG AND GYROCOMPASS
   (A.J. Taylor)

Ship speed is determined by a Chernikeeff log with sensor head 
approximately 0.25 m beyond the hull of the ship.  Because of a sensor 
failure on the previous cruise a new unit was installed in Punta Arenas 
and zeroed whilst at the dock.  Initially when underway a nominal 
calibration was applied, but at 11.0 kt smg as determined by a 
navigation unit (decca Mk52), the indicated speed was 12.24 kt, so a 
scaling was introduced to bring the two into agreement.  The same 
adjustment was made to the port/starboard component.

On January 8 the sensor head was rotated approximately 5° anti-clockwise 
to reduce a spurious athwartship drift of about 1.3 kt at full speed.  
Improved log calibrations will be obtained by comparison with ADCP data 
(including the zig-zags) but because this will have a minor impact on 
'bestnav' calculations we do not anticipate recalculating navigation for 
this reason.

Two S.G.Brown gyrocompass units (SGB1000) are installed on the Bridge.  
Because of a long lag noted with unit 1 on the previous cruise, unit 2 
was employed for primary navigation throughout cruise 199.  The output 
was logged via a level A microprocessor at 1 Hz and was free of gaps.  
The accuracy of heading is discussed in the following section.


C) ASHTECH GPS3DF INSTRUMENT
   (S.R. Thompson)

This instrument, newly acquired for the cruise, measures not only the 
position but also the three dimensional attitude of the ship from the 
GPS system, i.e.  ship's roll, pitch and, most significantly for the 
ADCP work, heading.  The determination of attitude is performed by an 
array of four antennas approximately in the form of a square of side 8m.  
Data were logged in the deck unit of the receiver at 0.2 Hz frequency 
(because the level A failed to work reliably) and down loaded to the SUN 
workstations twice per day.

King and Cooper (1993) have described details of the instrument, its 
installation and preliminary results on a 7 day trial cruise of RRS 
Discovery.  They demonstrated that the gyro error is a function of 
ship's heading and also that it changes with time after a ship maneuver: 
in port they confirm the accuracy claimed by the manufacturer of 0.05°.  
On cruise 199 we elected to use the second of the two ship's Gyro 
compass units, (i.e. a different one from King and Cooper), and our 
preliminary results show that this instrument also experiences gyro 
error related to the ship's heading and time-dependent errors after 
maneuvering.  Also long term drift of the gyro is apparent.  For both 
instruments, these variations are of the order of 1°.

Data quality control was implemented in the manner described by King and 
Cooper (loc cit).  For reasons not currently understood only 
approximately one third of one minute averages of the difference between 
Ashtech and gyro headings contain data, far less than they encountered 
at the same latitude in the North Atlantic.  Ten minute average 
differences have also been constructed and assembled in 5 day summaries.  
These will be used in post processing of the ADCP data and are expected 
to bring significant changes especially for underway estimates of 
currents.


REFERENCE

KING, B.A. and E.B. COOPER, 1993.  Comparison of ship's heading 
  determined from an array of GPS antennas with heading from 
  conventional gyrocompass measurements. Submitted to Deep-Sea Research.


2.10  UNDERWAY OBSERVATIONS

A) ECHOSOUNDING
   by: A.J. Taylor 

EQUIPMENT
The bathymetry equipment installed on RRS Discovery consists of:- Hull 
mounted transducer, Precision Echosounding (PES) 'fish' transducer, and 
Simrad EA500 Hydrographic Echosounder.


OPERATION
The Simrad Echosounder was used during the cruise for bottom detection 
and determining the height of the CTD off the bottom during casts.  
While in bottom detection mode the depth values were passed via a RVS 
level A interface to the level C system for processing.  Data were 
logged at a 30 second interval.

The transducers were connected to the Simrad equipment via an external 
switch.  A uniform sound velocity of 1500 meters/sec was used during the 
cruise.

A visual display of the return echo was displayed on the Simrad VDU.  
Hardcopy output was produced on a color inkjet printer and a Waverley 
thermal line-scan recorder.


PERFORMANCE
While on station and steaming during the initial few weeks of the 
cruise, the PES fish transducer was used.  This gave good return signals 
on station and adequate return signals whilst steaming at 10 knots.  
After the second week the return signal when steaming deteriorated 
rapidly and the hull transducer was used whilst underway.  Upon recovery 
of the fish on day 025 prior to steaming for Capetown, it was found that 
the lowest section of fairing was split in two.  This was probably 
hitting the fish and the cause of noise whilst steaming.  The fairing 
was replaced before being re-deployed on day 028, and a good signals 
were obtained whilst underway for the remainder of the cruise.

When coming on station the PES fish sank considerably from its steaming 
depth: this resulted in a 17m offset between the PES fish and the hull 
transducer on the graphic display.  The fish returned a lower depth than 
the hull transducer.  The amount of cable submerged whilst on station 
was measured to be approximately 22m, thereby accounting for the offset.

The Hewlett Packard inkjet printer developed a fault after one week and 
was replaced by the Waverley line-scan recorder.  This was quite 
unreliable and was itself replaced, when a new inkjet printer was 
delivered by the Capetown pilot on 27 January.

As is well known the automatic depth finder performance is adversely 
affected when the signal to noise ratio is small.  In these 
circumstances the digitally recorded data is frequently unreliable.  
Given strip-chart records the situation can be recognized and rectified.  
Except for the first few and the last few days, such records are 
unavailable on cruise 199.  Consequently the overall quality of the 
depth measurements is very disappointing.  (Note added by P.M.Saunders, 
9 Feb '93).


B) METEOROLOGICAL MEASUREMENTS
   (K.J. Heywood and P.K. Smith) 

The meteorological monitoring system used on RRS Discovery comprises the 
following instruments:-

 o  an R.M.  Young Instruments Type 05103 wind velocity propeller - 
    vane sensor, located on the foremast to port.
 o  two Vector Instruments psychrometers, located on the foremast to 
    starboard (serial numbers 1072 and 1073).
 o  (1073 was replaced by 1071 during the cruise).
 o  two Didcot cosine collector PAR sensors (spectral range 400-700nm) 
    located port and starboard on the foremast (serial numbers 0150 
    and 0151 respectively).
 o  two Kipp and Zonen total irradiance sensors located on the 
    foremast to port and starboard (serial numbers 92015 and 92016 
    respectively).
 o  an Eppley longwave pyrogeometer located on the foremast top pole 
    (serial number 26207F3).
 o  a hull-mounted RVS/RS Components platinum resistance thermometer, 
    recording sea surface temperatures.
 o  a V”is”l” DPA21 aneroid barometer, located in the main lab.
 o  a Gill sonic anemometer located on the foremast to starboard.
 o  a ship borne wave recorder.

Unlike most shipboard instruments that have a dedicated Level A 
interface, the metlogger PC emulates a standard Level A interface and 
transmits the data directly to the Level B in Ship Message Protocol 
(SMP).  The data are transferred to the Level C and then reformatted 
from Level C to PSTAR format to allow processing under Unix, using a 
series of pexec scripts based on the set of scripts used for the IOSDL 
Multimet system.  Data were recorded as 1 minute averages.


PROCESSING
The Unix shell script metexec0 was used to retrieve data from the Level 
C and convert them into PSTAR format.  Metexec1 was used to calibrate 
all instruments apart from the aneroid barometer and wind direction 
output from the wind velocity sensor.  Ship's navigation data including 
gyro heading (bestnav, derived from GPS and dead-reckoning) were merged 
with the met file by metexec2.  Metexec3 and metexec4 were not normally 
used for this cruise.  A combination of the ship's velocity components 
and heading was used in metexec5 for the conversion from relative to 
absolute wind velocities.  Metexec6, an appending script was used to 
generate a full time series from the individual files, metexecp was used 
to produce plots, and the Pstar program metflx was used to derive wind 
stress and heat fluxes.


CALIBRATION
With the exception of the aneroid barometer and wind direction output 
from the wind velocity sensor where any conversion or calibration is 
performed by the metlogger PC and were therefore logged through to the 
Level B as calibrated output, all instruments were calibrated during 
PSTAR processing of the met. data.  The calibration algorithms applied 
were derived either from manufacturers calibration certificates or from 
calibrations undertaken by RVS and IOSDL prior to the cruise.  Details 
are given in Table M1.


PROBLEMS ENCOUNTERED

AIR TEMPERATURES
The RVS PC display system showed slightly higher readings than expected.  
This was due to the calibration coefficients being only nominal values.  
Also the calibration file used a 2nd order polynomial, whereas the IOS 
calibration uses a 3rd order polynomial.  Using the calibration data for 
each psychrometer, new values were calculated and entered into the 
calibration file.  These gave good readings on the display.  The correct 
3 order coefficients were in the Pstar calibration file.

On 29/12/92 (day 364) the port psychrometer data became very noisy.  It 
was replaced and new calibration coefficients entered into the 
calibration file (/pstar/src/extras/cal/met 199.  cal).  There is a gap 
in the port data between 1600 hrs and 1845 hrs.  No further problems 
occurred during the cruise.


LONG WAVE RADIOMETER
This gave good readings at the start of the cruise, but began giving 
some low readings during 1st January (day 367).  The signal slowly 
deteriorated becoming more erratic.  The battery was replaced on 16th 
January (day 382) and good readings were obtained for the rest of the 
cruise.


SONIC ANEMOMETER
The Asymmetric Sonic Anemometer was mounted on the foremast with North 
facing forward.  The system gave good readings.  The system stores 
processed data on both hard disk and floppy disk.  To store the raw data 
an optical disk was installed with a capacity of 20 days' data.  There 
was some difficulty in setting up the software but eventually the 
optical disk recorded raw data.  There was some complex interaction 
between the system clock and the optical disk software.  As the software 
needs the time and date information in the data files and in naming the 
files, the software halts if the internal clock is in error.  This error 
occurred between once in 3 days to 3 times in a day.  Re-booting and 
resetting the time and date resumed normal operation.


SHIP BORNE WAVE RECORDER
The computer and associated software worked well during the cruise with 
very few errors.  The signal amplification/conditioning unit showed a 
large d.c. offset and low amplitude signal for the Port Pressure 
Transducer.  This transducer was flushed, which considerably reduced the 
d.c. offset and increased the signal amplitude.  Further flushing 
produced a further improvement but there was still a small d.c. offset 
and the amplitude remained slightly smaller than the starboard pressure 
transducer.  The last calibration was at the refit and a d.c. offset was 
noted then.


MET OBSERVATIONS DURING THE CRUISE
Weather conditions during the cruise were remarkably clement, with the 
exception of a storm in mid January.  The maximum wind speed observed 
was 28 ms-1 on 13th January, producing the largest waveheights.


TABLE M1: Calibration coefficients for the met. sensors

Measurement		Calibration coeffs		source
					if not IOS
		y=a+bx+cx2+dx3
	a	b	c	d
Wind speed	0	0.1	0	0	mfr
Wind dirn	0	1.0	0	0	mfr
swet	-21.63646	2.580562e-3	7.893778e-6	0.660868e-9
sdry	-20.18834	9.733870e-4	7.835114e-6	0.525038e-9
up to day 364
pwet	-23.71101	6.848060e-3	5.626587e-6	1.077627e-9
pdry	-23.84735	5.788879e-3	5.648462e-6	0.907665e-9
after day 364
pwet	-24.38268	6.720888e-3	5.840227e-6	0.969597e-9
pdry	-23.36777	5.245053e-3	5.784058e-6	0.882978e-9
sea	0.26705	0.99189	2.9755e-4	0	RVS
longwave	0	0.23364486	0	0

y=x/(ab)
pPAR	5	12.86e-6
sPAR	5	12.87e-6
pirr	2	48.49e-3
sirr	2	43.63e-3


C) THERMOSALINOGRAPH MEASUREMENTS
   by: S. Cunningham 

INSTRUMENT AND TECHNIQUE
Continuous underway measurements of surface salinity and temperature 
were made with a Falmouth Scientific Inc. (FSI) shipboard mounted 
thermosalinograph (TSG).  Salinity samples were drawn from the non-toxic 
sea water supply at four hourly intervals, and used to calibrate 
conductivities obtained from the TSG.  The instrument was run 
continuously throughout the cruise.

The TSG comprises of two FSI sensor 'modules', an Ocean Conductivity 
Module (OCM) and an Ocean Temperature Module (OTM) both fitted within 
the same laboratory housing.  Sea surface temperature is measured by a 
second OTM situated on the suction side of the non-toxic supply in the 
forward hold.  The non-toxic intake is 5 m below the sea surface.

Data from the OCM and OTM modules are passed to a personal computer 
(pc).  The pc imitates the traditional Level A system, passing it to 
Level B at 30 second intervals.


SENSOR CALIBRATIONS
The temperature modules are installed pre-calibrated to a laboratory 
standard and laboratory calibration data are used to obtain four 
polynomial coefficients.  A similar procedure is employed for the 
conductivity module.

UNDERWAY SALINITY SAMPLING
Salinity samples were drawn from the non-toxic supply at four hourly 
intervals.  These samples were then analyzed on a Guildline 8400 using 
standard sea water batch P120.


CALIBRATION OF TSG SALINITIES AGAINST UNDERWAY SALINITY SAMPLES
TSG conductivity measurements at 30 second interval were median de-
spiked, discarding data more than 0.01 mmho/cm from a mean computed over 
5 adjacent data values.  Conductivity of the bottle samples was 
calculated at a pressure of 0 dbar and at the temperatures of the TSG 
OTM.  The TSG data were merged onto the bottle data and the conductivity 
difference between the bottles and TSG calculated.  After excluding 
outliers, a linear regression between the conductivities was determined 
and applied to the TSG values.  TSG salinities were computed along with 
the difference from the bottle salinities.  This difference was filtered 
with a Gaussian filter of half width 12 hours and normalized peak height 
of 0.38.  TSG salinities were then corrected by adding the filtered 
difference.  A plot of the corrected salinity and temperature at the 
surface for the entire cruise is shown in Figure 7.


ESTIMATE OF THE TSG ACCURACY AND SALINITY RESIDUALS
Due to particular difficulties with the instrument, the estimate of 
salinity residuals has been split into two portions.  For the period day 
of year=359 to day=23 (389) the mean difference between the bottle and 
TSG salinities was -0.0009 with a standard deviation of 0.0145.  For the 
period day=23 to day=32 the mean salinity difference was 0.0005 with a 
standard deviation of 0.02.

Over the period from 23 0000Z to 27 0825Z the housing temperature sensor 
produced unreliable results.  A current leakage was found between the 
platinum resistance thermometer and the surrounding seawater.  This 
caused the probe to oxidize and eventually fail.  At about the same time 
the pumps for the non-toxic supply failed and an alternative set were 
switched on.  This caused a decrease in the flow rate and a 
corresponding increase in lag time for water from the non-toxic intake 
to reach the TSG, from approximately 5 to 10 minutes.  Degradation of 
the conductivity results is likely.  On day=26 at 0555Z the housing OTM 
was replaced.  For the period 23 0000Z to 26 0555Z a reconstructed 
housing temperature was derived from the remote temperatures.  Given the 
uncertainties in lag time and the alternative heating and cooling of the 
non-toxic supply through the ship (during this period for surface 
temperatures less than 20.2°C the supply is warmed and above that 
cooled) the reconstructed temperatures are not likely to be better than 
0.2°C.  The uncertainty probably accounts for most of the spread in the 
salinity residuals over this latter period.


D) SATELLITE IMAGE ACQUISITION AND PROCESSING
   (M.P. Meredith and V.C. Cornell)

EQUIPMENT AND FUNCTION
On this cruise equipment was installed for the capture, display and 
processing of polar-orbiting weather satellite imagery.  This consisted 
of an omni-directional VHF antenna mounted on the main mast, a pre-
amplifier to compensate for feeder cable losses of up to 10db, a Dartcom 
system II receiver, an 8-bit 15MHz microcontrolled interface to control 
the frequency and mode of the receiver, and an Apple Macintosh IIsi 
computer with the MacSat 2.1 software supplied jointly by Dartcom and 
Newcastle Computer Services.

The equipment was used to receive data sent from the NOAA satellites 10, 
11 and 12 via the Automatic Picture Transmission (APT) system at 137.50 
and 137.62 MHz.  Although the software allows the capture of 
geostationary weather satellite images, the hardware necessary for this 
was not present.  No attempt was made to capture images from polar-
orbiting satellites other than the NOAA series.

The data collected were from the Advanced Very High Resolution 
Radiometer (AVHRR), a five-channel radiometer featuring one visible, two 
near-infra red and two thermal infra-red channels, though the APT system 
only allows for the visible channel plus one infra-red channel to be 
received.  The APT system also reduces the spatial resolution of the 
data from its maximum of 1.1 km square at nadir to approximately 4 km 
square.  Data from almost all the radiometers' swath width is captured 
with MacSat;  an 800 x 800 pixel image covers approximately 3000 km 
square, and has a maximum of 256 digitization levels per pixel.


PROCEDURE
During the cruise, most of the longer satellite passes (>12 minutes) 
were captured.  Shorter passes generally did not contain enough noise-
free data to warrant their capture.  The vast majority of images were 
from the infra-red channel, since the previous cruise experienced serial 
error problems with the Auto Save function (the function enabling both 
channels to be acquired simultaneously), which led to the loss of the 
images.  Thus only one of the two channels was available, and the 
infrared data were deemed more useful than the visible for our purposes.

Once captured, the time/date, ship's position, and whether the satellite 
was in an ascending or descending pass was recorded, and a geographical 
overlay created for the image.  This shows lines of latitude and 
longitude, ship's position at time of acquisition, and, if relevant, a 
coarse coastline.  Three standard color palettes were created to enable 
depiction of sea brightness temperature.  One would not suffice since 
the manual contrast stretch facilities of MacSat (adjusting the RGB 
response curves for the image) were found to be very cumbersome, and the 
Auto Contrast function is only useful for gray scale images.

Color hardcopies were produced for each image by using the Mac's screen-
dump tool.  This creates a TeachText picture of the screen, which can 
then be printed to a postscript file, transferred to the Sun 
workstations using ftp, converted to a PCL file and outputted to the HP 
Paintjet printer.  This was considered a better procedure than using 
MacSat's print option, since not only can the whole image be displayed 
on one A4 sheet, but the geographical overlay can be also be printed on 
the image.

Some images were transferred to more sophisticated image processing 
software on the Suns;  this, along with the image file format and file 
archiving, is discussed elsewhere.


PROBLEMS
Difficulties encountered on the previous cruise concerning the gross 
inaccuracy of the geographical overlay were to a large extent resolved.  
Updated files containing the Keplerian orbital elements for the 
satellites were obtained by fax from Newcastle Computer Services on two 
occasions as a matter of course, and on a third (1st Jan), when an error 
in the orbital element calculations became apparent.  Also, the Mac's 
internal clock was corrected each day, since it gains approximately one 
second per day on GMT.  Such an error is not insignificant for 
satellites travelling at 27,000 km/h, and would greatly affect the 
positioning of the overlay if left unaltered for a number of days.  
However, even with these measures being taken, the overlay could still 
be as much as a degree or two out, and the uncertainty should be borne 
in mind when considering images without coastline in them.

Noise contamination of images was a frequent problem, and although 
MacSat has a noise reduction filter, this is of use only for 
presentation purposes and obviously cannot replace missing data values.  
Whether the problem was caused by atmospheric conditions, insufficient 
signal amplification or faulty hardware remains unknown.

A further unsolved problem is the overlay tool's failure to plot lines 
of latitude for descending satellite passes.  We think this can only be 
attributable to a bug in the program.

Initially, difficulties were encountered with the loss of images due to 
serial errors during acquisition.  This was caused by a slowing of the 
Mac to the point where it could not keep up with the incoming data 
stream, and was solved by ensuring that there were no telnet connections 
active, no print jobs queued and no Appleshare volumes present on the 
workspace at the time of capturing an image.


OBSERVATIONS
Several significant oceanographic features were observed in the 
satellite imagery captured during the course of the cruise.  The 
retroflexion of the Falkland Current at the Brazil Current was clearly 
visible, and when the thermosalinograph (TSG) showed an increase in 
temperature, the MacSat image revealed a warm ring shed from the 
conflict of the two currents.  Many of the images showed the position of 
the Subtropical Front to the north of the cruise track, and, towards the 
end of the cruise, the coastal upwelling region associated with the 
Benguela Current is clearly visible.  An Agulhas ring was possibly 
observed, but not certainly, since cloud contamination partially 
obscures the feature.  The cloud images also proved illuminating, 
especially during the severe storm encountered on the 13/14th January 
1993.


2.11  SHIPBOARD COMPUTING
      (M.G. Beney and V.C. Cornell)

RVS LOGGING SYSTEM 'ABC'
The RVS logging system comprises of 3 distinguishable parts or levels.  
Each level is referred to by one of the following letters A, B or C, and 
the whole system is called the 'ABC' system.

A Level A consists of a microprocessor based intelligent interface with 
firmware which collects data from a piece of scientific equipment, 
checks and filters it, and outputs it as SMP (ship message protocol) 
formatted messages.

There are two versions of dedicated Level A's, a MkI based on a 8085 
processor using CEXEC as the operating system, and a MkII based on a 
68000 processor running OS9 as the operating system.  In addition there 
are pseudo Level A's which are PC's around which a piece of equipment it 
based, which are also capable of generating SMP messages.

The Level B collects each of the Level A SMP messages and writes them to 
disk and backup cartridge tape.  The Level B monitors the frequency of 
these messages, and besides providing a central display for the data 
messages also warns the operator when messages fail to appear.  The 
Level B, which is based on a 68030 processor using OS9 as the operating 
system, collates the data and outputs it to the network.

The Level C, which is a SUN IPC (4/40), takes this data and parses it 
into RVS data files.  These data files are constructed on a RVS styled 
database for speed of access.

The following list shows the instrument Level As and the variables which 
were logged by the Level C.  The first column shows the name used by the 
Level A.  Brackets after the Level A name indicate whether it was a MkI 
(1), MkII (2) or IBM compatible PC (PC), based Level A.  The "adcp" data 
was collected directly by the Level C through one of its serial ports 
(ttya).  The data was written to the data file named in column 2 with 
the variable names shown in column 3.


Level A	Datafile	Variables
BOTTLES(1)	bottles	code
CTD_17C(2)	ctd_17	press temp cond trans alt oxyc oxyt temp2 
		cond2 deltat nframs
GPS_ATT(2)	gps_att	hdg pitch roll mrms brms attf sec
GPS_TRIM(2)	gps_trim	lat lon pdop hvel hdg svc s1-s5
GYRO_RVS(2)	gyro_rvs	heading
LOG_CHF(2)	log_chf	speedfa speedps
METLOGGR(PC)	metloggr	winspd windir pwettemp pdrytemp 
		swettemp sdrytemp seatemp ppar ptir spar
		stir lwave baro
MX1107(1)	mx1107	lat lon slt sln el it ct dist dir sat r status
SIM500(2)	sim500	uncdepth rpow angfa angps
SURFLOG(PC)	surflog	temp_h temp_m cond
WAVE(1)	wave	height
WINCH(PC)	winch	cabltype cablout rate tension
		btension comp angle


The following list shows data files which contained data directly 
collected by the Level C

	adcp_raw	rawampl beamno bindepth
	adcp	bindepth heading temp velew velns velvert 
		velerr ampl good bottomew bottomns depth 
	xbt	depth temp

The following datafiles were archived:
	relmov	gps	mx1107 
	bestnav	bestdrf	winch 
	wave	metloggr	surflog 
	adcp	adcp_raw	ctd and xbt.

These RVS archives have only limited life and are only intended as 
(fall-) backups.


PROCESSING OF DATA
Virtually all of the data processing was performed using the interactive 
"pstar" suite of about 300 documented programs (Alderson et al,1991).  
This continuously updated system is installed on RVS ships as well as at 
labs ashore.  RVS data files were converted to "pstar" data files using 
the program 'datapup'.


ARCHIVING OF PSTAR FILES
Archiving took place on a daily basis.  Copies were made of all 
processed files on Sony erasable magneto-optical disks.  These were 
mounted as standard unix file systems.  In addition files were copied to 
Quarter Inch Cartridge (QIC) tape in both raw sequential and unix tar 
format.  Six sides of optical disk data were taken ashore at the end of 
the cruise, totaling about 1.5 Gigabytes.


EQUIPMENT AVAILABLE ON CRUISE 199:
Personal Computers (Operating under Apple system 7.01)

3 Apple Macintosh Classics	(40 Mb Hard Disc, 4Mb RAM)
1 Apple Macintosh ClassicII	(40 Mb Hard Disc, 4Mb RAM)
1 Apple Macintosh II si 	(80 Mb Hard Disc, 5Mb RAM)
The last was connected to a Dartcom System II satellite image receiver.

Sun Workstations (Operating under Sunsoft's version 4.1.1)

Node name	Type		Ram	Hard Disc	Peripherals
					(Mb)		(Mb)
discovery1	IPC		12	2x327		Exabyte drive
					1x207		QIC 150 tape
discovery2	IPC		12	1x207		Magneto/optic
					1x1200		QIC 150 tape
discovery3	Sparc stn	8	2x327
discovery4	Sparc stn	8	2x237

Output devices:
 o  Apple LaserWriter II (Mono Laser Printer).
 o  Hewlett Packard Paintjet XL (InkJet Colour Plotter).
 o  Tektronix 4693RGB (Thermal transfer plotter).
 o  Hewlett Packard LaserJet III (Mono Laser Printer).
 o  NEC Pinwriter P5 (Dot Matrix line printer).
 o  Bruning Drum-type Pen Plotter.

NETWORKING
All PCs, workstations and a number of output devices were connected to a 
thin Ethernet  (10Base2) local area network.  The Sun workstations have 
integral Ethernet interfaces, the Apple Macintoshes were connected via 
external SCSI Ethernet interfaces.


REFERENCE

ALDERSON, S.G., GRIFFITHS, M.J., READ, J.F. and R.T. POLLARD, 1991.  
  PEXEX PROCESSING SYSTEM, Internal document, Institute of Oceanographic 
  Sciences Deacon Laboratory, about 450 pp.


2.12  CRUISE DIARY
      (P.M. Saunders)

22 DECEMBER DAY 357/1992
   RRS Discovery left Punta Arenas at 1700P (1400Z) with a pilot aboard, 
   about 9 hours later than planned.  All times are given as ship's time 
   and the relation of ship's time to GMT stated whenever the relationship 
   is altered.  The delay was occasioned by the late arrival of the customs 
   paperwork for the various items of airfreight.  Amongst these was the 
   CFC equipment which came on board, late on the 20 December.  A new emlog 
   was installed and an arbitrary calibration applied to yield reasonable 
   ship's speed.  The navigation and the Acoustic Doppler current Profiler 
   (ADCP) were logged from departure.
  
23 DECEMBER DAY 358
   Calm seas, some pitching motion as course is set 050° across the 
   Argentine shelf 0430 (0730Z).  At 0900 the first officer gave a safety 
   briefing and this was followed by a science briefing by the PSO.  At 
   1030 there was fire and boat drill, followed by a tour of the ship 
   pointing out escape routes etc.  Around 0130P (0430Z) the 
   thermosalinograph was started up.  At 0200 the Echosounder fish was 
   streamed and after repairs to the fairing clips RRS Discovery resumed 
   speed.
   
24 DECEMBER DAY 359
   Given continuing fair weather it was decided to undertake an ADCP 
   calibration exercise; this was performed between 1300 and 1600P.  The 
   results were satisfactory.  See the ADCP account in this report.

25 DECEMBER DAY 360
   A trial of the mid-ship winch was undertaken as station 12238 between 
   0628 and 0729P.  A depth of 500m was reached and, after recovery, 
   repairs were made to the winch scrolling gear and to the CTD, so that 
   the exercise proved fruitful.  Whilst the RRS Discovery continued 
   northwards towards the latitude 45°S, crew and scientific party 
   celebrated the festive occasion.
   
26 DECEMBER DAY 361
   A test station 12239 was started in approximately 4000m of water at 
   0830P and was concluded about 1130P.  The Rosette jammed after 5 firings 
   and the ctd display was very noisy.  The new altimeter unit worked well.  
   Lanyard tensions were reduced and some cables replaced.  An XBT was 
   launched.  A second station at the same location (45° 00'S 47° 30'W) 
   12240 to a depth of 2500m was more successful.  With the wind 25-30kts 
   samples were drawn on station, and at 1810P the ship turned west into an 
   ADCP/XBT section.  Some light rolling ensued.  

27 DECEMBER DAY 362
   A murky drizzly foggy morning turned into a bright sunny afternoon as 8 
   XBT/ADCP stations (12240-12247) were occupied in all.  The wind died 
   away and during passage, a tongue of cool surface water circa 8.5°C was 
   encountered with warmer water 11.5°C to both west and east; it was the 
   Falklands current.
   
COMMENCEMENT OF THE A11 SECTION (45°S, 60°W)
   
At 2000P station 122047, the first in the transoceanic section was 
begun: the water depth was about 250m and the initial objective was the 
Mid Atlantic Ridge nearly 1900 miles away.  In order to assure good ADCP 
data, stations in the western boundary current were assigned a minimum 
duration of 2 hours.

28 DECEMBER DAY 363
   Overnight stations in 500m, 1000m, and 1500m were occupied in calm seas 
   the last within and close to the western edge of the Falklands current.  
   Stations continued at 500m spacing down the slope, with spacing that 
   varied between 3 and 30 n-miles.
   
29 DECEMBER DAY 364
   Overnight the wind increased sharply and reached 35kts but by 0800P it 
   decreased to 20kts under cloudless skies.  Approximately 125kg of lead 
   was removed from the rosette to reduce wire tension for the deeper 
   casts.  On station 12256 started near noon and completed at 1600P the 
   deep western boundary current was detected;  a nepheloid layer of 
   thickness 400m defined it, at a depth below 4350m.  The weather was fine 
   enough for maintenance of the psychrometers on the foremast to be 
   carried out.
   
30 DECEMBER DAY 365
   Overnight the wind increased from the west to 30kts and the sea began to 
   build.  Station 12258 was begun at 0250P and after the cast had reached 
   2500m the ship's bow-thruster malfunctioned and the CTD/Rosette were 
   recovered by 0450P.  After repairs a second cast to the station was 
   begun; it reached 5500m and was completed by 1240.  (Subsequently it was 
   learned that one of the motors that rotated the thruster needed parts 
   which were not available on board.)  Use was made of the railway to move 
   the rosette to a protected position for sampling.  This proved helpful.

   Station 12259 was carried out between 1650.  and 2150 to a depth of 
   5630m;  by now seas had built and some difficulties were encountered in 
   hauling at the bottom of the cast.  Fire and boat drill engaged those 
   not involved directly in station work.
   
31 DECEMBER DAY 366
   At 0000 the ship's master-clock decided it had started a new year and 
   clock day was reset to 0.  Some difficulties are to be expected in the 
   subsequent processing of the data!!
   
   At this same time a station was started in about 5770m of water with 
   strong SW squalls and high seas.  This proved unwise.  About two hours 
   later it became quite evident that coupled with a strong current shear, 
   the wire could no longer be controlled.  Accordingly stn 12260 was 
   abandoned at a depth of about 2800m.  During the day wind and sea 
   subsided and soon after midday stn 12261 was begun in 5900m of water.  
   The station reached within 20m of the bottom where a very strong 
   nepheloid layer was encountered and all gear was recovered by 1700.  The 
   performance of the winch in these circumstances was very satisfactory.  
   At 2200 station 12262 was begun, again in nearly 5900m of water;  the 
   maximum expected water depth for the section was found between these 
   latter casts.  
   
1  JANUARY DAY 001/1993
   The New Year was welcomed whilst completing the station.  Again a very 
   strong nepheloid layer was seen.  Unfortunately apart from this success 
   little else went right on the day.
   
   At 0600 the ship hove to on station;  RRS Discovery remained in this 
   vicinity for the remainder of the day as both the engineers on board and 
   those at the RVS base, over 6000n-mi away, attempted to diagnose and 
   repair a defunct winch.  The timing was inopportune, occurring on a bank 
   holiday followed by a weekend.  To ensure a quiet night, there was no 
   work programme.

2  JANUARY DAY 002
   After considerable effort overnight the problem was identified.  A 
   faulty electrical component in the control logic circuit was found and 
   replaced with an identical unit from the main winch, which was 
   unserviceable.  At about 0630 a series of shallow lowerings was begun: 
   these were employed to fix the winch control settings, which were quite 
   different from those prior to the breakdown.  At 1620 station 12263 was 
   begun in approximately 5750m of water, in the location arrived at 
   approximately 36 hours earlier.  The weather for this entire period had 
   been (gallingly) fine.  Immediately after launch the transmissometer 
   failed, due to a cable connection adrift, but the cast was continued to 
   full depth.  On subsequent stations the transmissometer performed well.
   
3  JANUARY DAY 003
   The normal routine of station work was resumed with XBTs at a location 
   midway between CTD casts.  Mud waves were spotted and the chart recorder 
   of the Echosounder which had been malfunctioning repaired and activated.  
   At 1204 the level B system stopped logging and approximately 8 minutes 
   of data was lost.  This was during station 12265.  The CTD data was 
   recovered from the deck unit PS2 , but other data was lost.  On the 
   following station 12266 a strong nepheloid layer was again seen, 
   suggesting strong currents on the abyssal plain.
   
4  JANUARY DAY 004
   Fine weather and a flat calm prevailed and the depth of the abyssal 
   plain continued to shallow.  A large school of pilot whales investigated 
   RRS Discovery on station 12269, which was also noteworthy because the 
   rosette jammed in position 13 and all shallow samples were lost.  As the 
   ship steamed away from the station the flanks of the Zapiola ridge were 
   encountered at 2000P.  The action of the Echosounder chart recorder 
   continued erratically.  CFC measurements were halted because of 
   contamination.

5  JANUARY DAY 005
   On station 12270, 0100 - 0500P, the Rosette jammed at or near position 
   13 and samples were not collected at shallow depths.  Since the previous 
   station had experienced a similar sample loss, the failure to add a 
   second shallow cast was unfortunate.  Samples were collected in the rain 
   but the protection of umbrellas was deemed unnecessary.  After station 
   12271 a NEly wind came up and the ships progress was hindered.  The ADCP 
   lost penetration and subsequent analysis revealed the presence of the 
   bogus "current following the ship" of 50-80 cms-1 always(?) seen when 
   heading into a sea.  On station 12272 the rosette again jammed at mid 
   bottle so a second cast was made to 1500m depth.

6  JANUARY DAY 006
   On the overnight station 12273 bottles 9 10 11 were not cocked but the 
   Rosette again malfunctioned so that after the samples were drawn the 
   Rosette was stripped of all equipment for an overhaul.  The spare 
   Rosette (No 2) was mobilized and functioned satisfactorily for the next 
   station.  The wind and sea were subsiding but low temperatures prevailed 
   as the RRS Discovery  re-entered the sub-Antarctic zone.
   
7  JANUARY DAY 007
   On the overnight and morning stations the rosette performed 
   satisfactorily but on station 12277 all bottles were closed below 1500m 
   so a second cast was undertaken.  Together the casts lasted from 1115 to 
   1745.  After the Zapiola ridge with crests near 4900m, stations were now 
   on the abyssal plain with depths over 5300m.  At 1615 there was fire and 
   boat drill.  The performance of the ADCP continued poor and air was bled 
   from the sensor pod without significant improvement.
   
8  JANUARY DAY 008
   The clocks were advanced 1 hour at 0001P so that ship time was now GMT-
   2.  Station 12278 at 3545W which was completed at 0200 in a flat calm 
   had a depth of 5470m and was the maximum reached between the Zapiola 
   ridge and the mid-Atlantic ridge; on this and subsequent stations the 
   measurements differed substantially from the GEBCO chart.  Mud waves 
   continued to be seen.
   
   At 1530 in continuing flat calm seas the emlog, which had shown a cross 
   track drift of about 1.3 kts, was rotated anti-clockwise about 5° to a 
   more nearly correct direction.  On the completion of station 12280 at 
   1740 a second ADCP zig-zag calibration exercise was begun to attempt to 
   verify the gyro drift measured by the Ashtech GPS receiver.  The 
   experiment concluded at 2100 still in very calm seas.
   
9  JANUARY DAY 009
   In the early hours of the following morning a seal was spotted close to 
   the ship and the barometer began to fall.  At 0900 ships time the wind 
   began to freshen from the Southeast and the barometer fell 
   precipitately.  At the start of station 12283 the wind was 45 kts from 
   the south; almost immediately it began to diminish and by the end of the 
   station it was only 25 kts.  The lowering and handling of the ctd was 
   straightforward despite the conditions.
   
   A comparison was made between measurements made on leg5 of SAVE near 45S 
   and 41W (stns 290-293) and those on this cruise (12269-74).  The salts 
   and nitrates were in good agreement, the oxygens about 1.5% low and the 
   silicates 3% low.
   
10 JANUARY DAY 010
   During the night the wind continued to come westerly and the 
   considerable swell caused heavy rolling.  This was uncomfortable for the 
   ship's complement and on station led to very heavy snatch loadings.  For 
   the first time significant irregularities arose in the lay of the wire 
   on the storage drum.  At about 0745 station 12285 was commenced.  About 
   4m down a high swell caught the Rosette and the wire was instantaneously 
   so slack that it jumped off the sheave pair at the foot of the gantry.  
   The wire was stopped off on the top of the Gantry, and inboard the wire 
   was paid out, correctly rerouted and the load taken up again.  The 
   package was recovered on deck and a large kink located; about 20m of 
   wire was cut off and the end reterminated.
   
   At the same time the Rosette No 1 was restored since No 2 had starting 
   registering numerous misfires.  The station was then restarted at 1000 
   after a delay of 2hours 15 minutes, and proceeded normally until about 
   3500m on recovery when attempts were made to improve the lay of the wire 
   on the drum.  Eventually the station was completed at 1500.  Meanwhile 
   the sea was subsiding.  BAK reported a green flash at sunset.

11 JANUARY DAY 011
   The day started fair and concern for the CTD performance proved 
   unnecessary.  The regulation 3 stations were performed and the first 
   colored Macsat images with a grid of lat and lon lines and the position 
   of the ship were printed.  Some but not all of these features had been 
   available previously.  Prior to station 12289 two lead weights (125kg) 
   were restored to the Rosette in order to improve the shallow descent 
   rate on the down cast.  
   
12 JANUARY DAY 012
   A stiff northerly blew up during stn 12291 (1040- 1400) now in only 
   4400m of water.  The next stations were accompanied by increasing rigor 
   of the conditions.  On both of them the Rosette was moved forward on the 
   railway and sampling was undertaken on station.  The wind and sea 
   increased although during the evening the sky cleared.
   
13 JANUARY DAY 013
   At midnight the ship's clock, on which time this log is based, was 
   advanced one hour to become GMT-1.  On station 12293 in 3500m of water 
   (0130-0430) conditions deteriorated markedly and by recovery the wind 
   was blowing 45kts gusting to 55.  The wind was now from west-northwest 
   and despite clear skies continued to blow a gale; the seas were the 
   largest seen on the cruise so far.  We remained jogging, i.e. going 
   slowly upwind, for the rest of the day.  The ADCP functioned well and 
   remarkable inertial oscillations were seen with an amplitude exceeding 
   50 cms-1.

14 JANUARY DAY 014
   After midnight the wind began to build again and by 0400 reached 50-60 
   kts, slowly backing to the south of west.  The seas were, without 
   exaggeration, mountainous with continuous spume blown from the crests.  
   The pitching of the ship was severe but tolerable but the occasional 
   heavy rolling was very uncomfortable.  Not surprisingly the ADCP 
   functioned only poorly.  During daylight hours wind and seas moderated 
   only very slowly and not until 2000 was the ship able to run before the 
   seas towards the next station position.  

15 JANUARY DAY 015
   At 0320 RRS Discovery arrived on station and the work programme was 
   resumed.  The seas were moderate - as was the performance of the 
   Rosette.  A second cast was made to 1000m to collect samples in the 
   upper ocean.  The decision was made to increase station spacing to 50 
   nautical miles for the foreseeable future.
   
16 JANUARY DAY 016
   A series of routine stations were made in shallow water depths, until on 
   station 12298 (1050-1300) in 2500m of water the crest of the Mid 
   Atlantic Ridge was reached.  A mid-cruise break and PES survey had been 
   planned but in view of the recent enforced delay this was no longer 
   possible.  By now the sea had quieted down and the skies were clear.
   
   
THE TURNING POINT ON THE A11 SECTION (45°S, 15°W).

At 1300 RRS Discovery steamed away on a course 059° towards the coast of 
South Africa and the conclusion of the section just over 1700 miles 
away.  Within a short time a large iceberg was sighted (!) and at 1500 
was passed at a range of 6 miles.

17 JANUARY DAY 017
   A day of calm seas and routine station work.  Having crossed the ridge 
   warmer water is encountered at all levels.  A new inductive FSI 
   conductivity cell is fitted to the CTD and yields encouraging results.  
   A substitute Echosounder chart recorder is in action at last .  Light 
   rain fell about 1930.
   
18 JANUARY DAY 018
   At 0000 ships time the clocks are advanced 1hour so that ships time and 
   GMT now agree.  A sunny morning gives way to a rainy cloudy afternoon; 
   by 1900 the wind is northerly blowing 25-30 kts.  The umbrellas and 
   their clamps on the Rosette frame are in use for the first time.  The 
   transmissometer develops intermittent and persistent noise; it is not 
   clear whether the noise is oceanic or instrumental.  Casts continue at a 
   50 mile spacing up to station 12306 (2015 - 2345).  The surface 
   temperature remains near 13 -14°C.  I had expected it would rise before 
   now.  

19 JANUARY DAY 019
   An eventful day.  After the station it was decided to resume a 42 mile 
   spacing which had been characteristic of the leg on 45S.  During 
   steaming between stations 12307 and -8 two remarkable topographic 
   features were encountered.  The first of these was seen at 0930 (XBT 72) 
   at location 40 58S and 6 01W; a seamount was detected rising to about 
   2300m from a sea floor near 3700m.  This was tentatively identified as 
   the flanks of the Admiral Zenker seamount.  As the proposed site of the 
   CTD station was neared, a second seamount was observed.  This rose to a 
   depth of 750m at 1054 at which point XBT 73 was dropped, 40° 48'S 5° 
   40'W.  The seamount was flat topped (a Guyot) and for a distance of 
   about 6 miles the depth was less than 1000m.  A further 8 miles on, 
   station 12308 was completed in 3700m of water.  There is no indication 
   of the seamount on any charts available to us; the name New Discovery 
   Seamount is proposed.  An overcast morning gave way to a sunny day 
   although a brisk NW'ly wind persisted.
   
20 JANUARY DAY 020
   Station 12310 started in conventional fashion just before 0100, but as 
   the Rosette was raised towards the surface a wave carried it upwards, 
   the wire went slack and jumped off the sheave pair at the foot of the 
   Gantry.  This was a repeat of the event of station 12285 on the 10th of 
   January.  Eventually the package was recovered, 35m of wire removed, a 
   new termination made and the cast restarted about 0300.
   
   For much of the day a moderate Westerly swell persisted and made the 
   station work slightly difficult for the winch drivers.  At the end of 
   station 12311 when the package was recovered a kink was found in the 
   wire which required cutting off about 10m of wire and a retermination - 
   for the second time in the day.
   
21 JANUARY DAY 021
   During the night the swell diminished and station 12313 in over 5000m of 
   water allowed the wire lay on the drum to be improved substantially.  
   Surface water temperatures have now risen to 16°C but the absence of a 
   marked subtropical convergence (RRS Discovery at 0700 is at 38.7S) has 
   surprised a number on board.  After station number 12315 we crossed the 
   Greenwich Meridian at 2025 , a minor milestone.  The crossing was made 
   at the start of the third ADCP calibration exercise 2020 -2300 in which 
   alternate courses were 015° and 105°.
   
22 JANUARY DAY 022
   The station work continues.  After station 12316 maintenance work was 
   carried out on the rosette and CTD cabling was replaced.  Nevertheless a 
   noisy transmissometer record was obtained.  Shortly before station 12318 
   the surface salinity exceeded 35 for the first time (near 37°S 2°E).
   
23 JANUARY DAY 023
   Calm seas continue but the station spacing is augmented to 60 miles in 
   order to anticipate a potential medical emergency and permit a dash to 
   Cape Town if required.  During the course of the day a remarkable lens 
   of cool saline water is seen by XBTs 85-88 and CTD station 12320 and 
   approximately 100 miles across.  This takes the form of a 600m deep 
   thermostad of temperature 13.5°C and salinity 35.2 which is capped by 
   warmer fresher water.  There is speculation that this is the remnant of 
   an Agulhas ring, shed in the retroflection zone which has overwintered 
   south of the convergence.  But it is much cooler and fresher than any 
   observed before.  After passage through the ring the water freshens to 
   34.95 and temperature 18.5°C; perhaps Deacon's assertion (1937) that the 
   seasonal migration of the sub-tropical convergence is large in this area 
   with a maximum northwards location in summer is being verified on the 
   cruise.  At about 1930 there is an abrupt jump on the thermosalinograph.  
   The salinity rises to 36 and the temperature to 20°C.  Hallelujah! The 
   latitude is 35° 40'S and the longitude 5° 00'E.
   
24 JANUARY DAY 024 
   The routine continues in calm clear subtropical weather with 60 mile 
   spacing of the stations.  Even underway the ADCP penetration is 300m.  
   For the past few days the winch operation under light loads has been 
   erratic; lets hope it lasts to Cape Town.  In the late afternoon a 
   Barbecue on the after deck whist the ship was on station 12324 was a 
   pleasant social occasion.
   
25 JANUARY DAY 025 
   Today we passed through what is certainly an Agulhas ring.  It took 20 
   hours and involved stations 12325 and 12326 and XBTs 097 - 102.  The 
   15°C isotherm went from a depth of 100m or less outside the ring to over 
   350m within the ring.  The extreme locations were 33° 49'S, 8 48°E to 
   33° 07'S, 10° 44'E, a distance of 105 n-miles.  Both of the stations 
   involved had problems.  On station 12325 the rosette firing hung up at 
   bottle 11; there were no samples above 1500m.  Consequently a second 
   cast was made to 1500m.  On station 12326 a number of the hydraulic 
   units shut down after start-up, attributed to a frozen cable-hauler, and 
   the cast was delayed 30 minutes.  During this cast the decision was made 
   to proceed to Cape Town to put ashore the PSO whose medical condition 
   was causing him and others concern.  Prior to departure the Echosounding 
   fish was brought on board.  It was decided to launch XBTs every 2 hours 
   on the way in.  Dr. King agreed to act as PSO.
   
26 JANUARY DAY 026
   XBTs continued as RRS Discovery steamed into a stiff SE'ly wind, and 
   later a 3 kt current.  For only the second time in the cruise the ADCP 
   data return was zero.  The thermosalinograph failed due to a defective 
   temperature element, which was replaced.  It had given poor data for 3 
   days.
   
27 JANUARY DAY 027
   Clocks were advanced one hour to bring ships time to GMT + 2.  Just 
   outside Cape Town harbour, 2 miles off Green Point and at about 1200, 
   the ship was met by a small boat and the PSO was put aboard.  By 1330 
   the ship was underway and a speedy northward passage at an average speed 
   of 13.5 kt was then made, with XBTs at 4 hourly intervals, to reach the 
   eastern of the line and work south-westward from there toward station 
   12326.  The ADCP housing was bled of air and repairs were made to clips 
   on the Echosounder fairing.  A new printer was installed for the 
   Echosounder and for the first time excellent records were obtained

28 JANUARY DAY 028
   Station 12327 was commenced in 230m of water at 0730 and by 0800 was 
   completed.  Because of the pressure of time the decision was made NOT to 
   remain for a minimum of two hours on station to obtain good ADCP records 
   as we had in the WBC.  On the following station in just under 500m of 
   water, at 1045 the Echosounding fish was deployed.  Thereafter stations 
   were occupied at water-depth increments of 500m and at distances of 
   between 10 and 40 n-miles, down the slope.  The last station occupied on 
   this day was 12332 in 2500m of water.

29 JANUARY DAY 029
   A superb calm day with a green flash at sunrise.  Four stations were 
   occupied today with the last, 12336, in a depth of water just under 
   4000m.
   
30 JANUARY DAY 030
   Today between 0530 and 0900 the last station 12337 was occupied at a 
   distance of only 43 n-miles from station 12326.  Thus the line is 
   satisfactorily completed - a tribute not only to the entire scientific 
   party but also to the entire ship's complement.

END OF A11 SECTION

Between 1200 and 1530 winch trials were carried out with the aim of 
improving the performance of the inboard compensation unit, and also to 
test the performance of the Mk 5 CTD.  Unfortunately neither was 
successful, and at the end of them the Echosounding fish was recovered 
and course was set for Cape Town.  Underway data logging was concluded 
at 2400 and watches were stood down at 1600.

31 JANUARY DAY 031
   In light winds the ship made good speed so that by 1720 it was possible 
   to start the fourth ADCP calibration exercise of the cruise.  The zig-
   zags were conducted on courses 105° and 015° respectively and ended at 
   2040.
   
1 FEBRUARY DAY 032
   The ship docked in Cape Town at 0830, concluding a most successful 
   cruise.


ACKNOWLEDGEMENTS

This cruise, a UK contribution to the World Ocean Circulation Experiment 
(WOCE), was made possible by the parent body of (almost) all of the 
participants, namely The Natural Environment Research Council.  
Substantial support was also furnished by Ministry of Defense through 
the MoD/Research Council's joint scheme and by the generous provision of 
XBTs from DNOM, Taunton.

The scientific party is grateful to the professional dedication of the 
Master, Captain Keith Avery, the officers and entire crew of RRS 
Discovery, - especially for the smooth running of a long cruise 
encompassing both Xmas and the New Year.  We also wish to acknowledge 
the support of the shore-side staff of the Research Vessels Base (Barry) 
and Mr. R. Bonner (IOSDL) for their expertise in the mobilization and 
demobilization of the cruise in distant ports.

____________________________________________________________________________________________________________________________
____________________________________________________________________________________________________________________________


CTD STATION LIST

	    date		time, gmt						 depth, m		Samples
 Stn   Cast     mmddyy  start	bottom	end	latitude	longitude      uncwtr	ht off 	wire	max  p	no     notes
													
12247	1	122792	2300	2312	2340	44  58.99  S	60  00.12  W	237	5	233	235	6	CFC
12248	1	122892	0143	0206	0229	44  59.66  S	59  56.35  W	476	8	455	461	9	CFC
12249	1	122892	0424	0458	0532	44  58.98  S	59  46.96  W	1007	9	963	971	10	
12250	1	122892	0936	1018	1109	44  58.85  S	59  07.14  W	1504	11	1480	1481	11	
12251	1	122892	1429	1516	1622	44  59.38  S	58  33.03  W	1908	10	1860	1891	7	CFC
12252	1	122892	1739	1831	1948	44  59.28  S	58  24.85  W	2603	10	2563	2613	18	
12253	1	122892	2112	2216	2338	44  59.93  S	58  21.71  W	3139	14	3080	3137	19	
12254	1	122992	0216	0325	0511	44  59.68  S	57  49.19  W	3447	9	3399	3455	19	
12255	1	122992	0915	1050	1258	45  00.59  S	57  24.73  W	4011	7	3965	4049	19	I
12256	1	122992	1509	1652	1844	45  01.16  S	56  59.79  W	4773	11	4755	4841	23	CFC
12257	1	123092	2209	0012	0240	45  01.26  S	56  29.90  W	5304	11	5313	5399	22	CFC
12258	2	123092	0817	1018	1239	45  01.47  S	55  45.28  W	5497	14	5555	5609	24	
12259	1	123092	1659	1904	2144	44  58.85  S	54  47.41  W	5648	28	5836	5765	24	CFC
12260	1	123192	0323	0501	0630	45  01.23  S	53  50.68  W	5784	-99	3121	2763	9	
12261	1	123192	1529	1739	1955	44  56.33  S	52  49.00  W	5901	21	5977	6037	24	CFC
12262	1	010193	0108	0320	0528	45  02.14  S	51  44.47  W	5916	18	5950	6051	23	
12263	1	010293	1919	2118	2331	45  02.34  S	50  44.74  W	5763	19	5795	5893	24	CFC
12264	1	010393	0324	0512	0710	45  01.47  S	49  45.10  W	5562	11	5547	5685	24	
12265	1	010393	1108	1259	1510	45  00.23  S	48  46.16  W	5390	10	5373	5499	24	CFC
12266	1	010393	1857	2047	2246	44  59.84  S	47  45.75  W	5271	18	5245	5367	23	
12267	1	010493	0248	0436	0639	45  00.58  S	46  45.22  W	5206	4	5185	5311	20	
12268	1	010493	1027	1208	1402	45  00.17  S	45  45.26  W	5127	12	5100	5223	23	
12269	1	010493	1750	1931	2124	44  59.33  S	44  44.39  W	5088	6	5065	5179	13	
12270	1	010593	0110	0256	0452	44  59.89  S	43  45.12  W	4899	12	4866	4977	15	
12271	1	010593	0855	1050	1253	44  59.98  S	42  45.23  W	5201	5	5205	5305	24	CFC
12272	1	010593	1808	2001	2208	44  59.62  S	41  45.07  W	4964	16	4946	5019	9	
12272	2	010593	2235	2315	0006	44  57.87  S	41  45.72  W	4924	-99	1500	1513	16	
12273	1	010693	0541	0740	0948	45  00.10  S	40  45.44  W	4980	13	4960	5055	24	CFC
12274	1	010693	1427	1606	1801	44  58.87  S	39  45.79  W	4990	6	4996	5075	23	
12275	1	010793	2229	0010	0202	44  58.90  S	38  43.82  W	4866	8	4842	4941	23	CFC
12276	1	010793	0612	0805	1011	45  00.55  S	37  42.91  W	5123	12	5155	5215	23	
12277	1	010793	1419	1611	1821	44  59.23  S	36  44.71  W	5328	6	5334	5457	24	
12277	2	010793	1925	2002	2037	44  59.72  S	36  45.03  W	5328	-99	1250	1264	12	
12278	1	010893	0027	0214	0417	44  59.43  S	35  45.06  W	5490	11	5470	5607	24	
12279	1	010893	0824	1013	1209	44  59.82  S	34  45.83  W	5311	8	5290	5413	23	CFC
12280	1	010893	1557	1742	1936	44  59.47  S	33  46.29  W	5172	4	5155	5267	24	
12281	1	010993	0115	0258	0450	45  00.88  S	32  46.44  W	5124	9	5092	5209	23	CFC
12282	1	010993	0850	1035	1232	45  00.11  S	31  43.23  W	5187	8	5170	5281	23	
12283	1	010993	1649	1847	2043	44  59.33  S	30  45.53  W	5096	12	5070	5185	24	CFC
12284	1	011093	0140	0346	0545	44  59.93  S	29  46.54  W	4933	15	4938	5009	22	
12285	1	011093	1209	1410	1659	44  59.87  S	28  44.49  W	4726	8	4695	4795	22	CFC
12286	1	011093	2048	2234	0021	45  00.32  S	27  46.34  W	4532	10	4510	4587	21	
12287	1	011193	0420	0603	0758	45  00.49  S	26  44.13  W	4764	9	4755	4853	23	CFC
12288	1	011193	1133	1326	1515	44  59.58  S	25  43.88  W	4648	8	4612	4717	21	I
12289	1	011193	1904	2040	2225	45  01.11  S	24  44.97  W	4523	11	4570	4605	21	CFC
12290	1	011293	0201	0334	0513	44  59.25  S	23  43.44  W	4221	12	4200	4259	20	
12291	1	011293	0848	1019	1158	44  59.65  S	22  45.72  W	4438	14	4405	4471	22	CFC
12292	1	011293	1608	1743	1918	45  00.89  S	21  44.24  W	3981	7	4108	4185	20	
12293	1	011393	0028	0156	0321	44  59.69  S	20  42.84  W	3527	17	3534	3599	22	CFC
12294	1	011593	0425	0554	0727	44  59.28  S	19  44.55  W	3830	15	3850	3895	10	
12294	2	011593	0810	0844	0917	44  58.70  S	19  45.83  W	3931	-99	1000	1008	12	
12295	1	011593	1338	1522	1656	45  00.91  S	18  34.32  W	3760	17	3906	3929	20	CFC
12296	1	011593	2106	2229	2353	45  00.03  S	17  23.82  W	-999	23	3710	3787	21	
12297	1	011693	0419	0547	0708	44  59.30  S	16  13.50  W	3322	10	3290	3327	19	CFC
12298	1	011693	1145	1253	1357	45  00.39  S	15  00.50  W	2757	23	2715	2747	17	
12299	1	011693	1824	1953	2114	44  32.66  S	14  00.18  W	3300	10	3335	3399	18	CFC
12300	1	011793	0133	0258	0421	44  06.73  S	13  00.66  W	3727	12	3658	3733	19	
12301	1	011793	0823	0946	1115	43  40.01  S	12  01.24  W	3612	12	3650	3709	20	CFC
12302	1	011793	1518	1644	1815	43  14.00  S	11  02.67  W	4006	10	3970	4049	19	CFC
12303	1	011793	2233	2355	0124	42  49.20  S	10  05.30  W	3840	11	3810	3877	22	CFC
12304	1	011893	0547	0712	0847	42  22.27  S	9   05.17  W	3841	7	3765	3843	19	
12305	1	011893	1302	1430	1558	41  55.79  S	8   10.09  W	3991	10	3964	4043	21	CFC,I
12306	1	011893	2023	2151	2320	41  31.40  S	7   12.31  W	3715	68	3730	3769	19	
12307	1	011993	0311	0449	0624	41  09.32  S	6   24.00  W	4066	2	4065	4123	20	CFC
12308	1	011993	1218	1343	1512	40  42.26  S	5   26.50  W	3718	10	3680	3755	20	
12309	1	011993	1809	1938	2102	40  25.38  S	4   49.82  W	3979	10	3964	4023	19	CFC
12310	1	012093	0252	0449	0638	40  04.98  S	4   02.44  W	4627	6	4605	4709	22	
12311	1	012093	1030	1229	1414	39  43.22  S	3   15.24  W	4488	11	4507	4593	24	CFC
12312	1	012093	1758	1941	2133	39  21.31  S	2   28.67  W	4561	12	4535	4631	23	
12313	1	012193	0107	0255	0443	38  58.22  S	1   41.36  W	4924	11	5038	5151	23	
12314	1	012193	0814	1012	1207	38  36.46  S	0   56.54  W	4983	11	4996	5107	22	
12315	1	012193	1539	1733	1933	38  14.88  S	0   09.74  W	5184	10	5180	5299	23	CFC
12316	1	012293	0013	0202	0359	37  52.89  S	0   35.51  E	5013	10	4997	5107	22	
12317	1	012293	0733	0918	1107	37  31.26  S	1   21.00  E	5074	10	5080	5193	22	CFC
12318	1	012293	1435	1627	1825	37  09.08  S	2   06.23  E	5106	5	5135	5209	23	
12319	1	012293	2146	2335	0127	36  47.42  S	2   51.51  E	5154	10	5155	5267	24	CFC
12320	1	012393	0623	0815	1019	36  16.60  S	3   55.53  E	5190	12	5195	5305	23	CFC
12321	1	012393	1522	1715	1903	35  44.79  S	5   00.15  E	5201	12	5220	5307	23	CFC
12322	1	012493	2357	0200	0404	35  12.76  S	6   02.17  E	5257	10	5270	5369	24	
12323	1	012493	0915	1058	1247	34  42.33  S	7   04.20  E	5219	10	5220	5337	24	CFC
12324	1	012493	1751	1943	2159	34  09.16  S	8   07.24  E	4989	9	5035	5103	22	
12325	1	012593	0301	0457	0638	33  40.82  S	9   08.81  E	5017	5	5065	5135	23	CFC
12325	2	012593	0820	0903	0955	33  40.25  S	9   07.97  E	5019	-99	1500	1502	23	CFC
12326	1	012593	1547	1750	1944	33  05.25  S	10  08.97  E	4999	4	5075	5103	23	CFC
12327	1	012893	0533	0550	0604	30  13.59  S	15  37.16  E	238	4	230	233	6	CFC
12328	1	012893	0849	0915	0939	30  28.27  S	15  08.12  E	471	8	465	465	9	CFC
12329	1	012893	1101	1138	1209	30  34.23  S	14  58.84  E	999	9	992	997	12	CFC
12330	1	012893	1325	1411	1454	30  40.29  S	14  47.44  E	1497	10	1505	1495	12	
12331	1	012893	1612	1703	1759	30  45.31  S	14  38.59  E	1986	10	1965	1985	14	CFC
12332	1	012893	1948	2047	2145	30  53.45  S	14  22.05  E	2498	10	2460	2503	16	
12333	1	012993	0046	0151	0301	31  14.14  S	13  44.98  E	3044	9	3012	3063	18	CFC
12334	1	012993	0611	0733	0856	31  32.54  S	13  09.65  E	3497	10	3475	3531	18	
12335	1	012993	1303	1427	1553	31  57.82  S	12  21.75  E	4002	7	3980	4055	21	CFC,I
12336	1	012993	1955	2127	2305	32  19.16  S	11  38.47  E	4412	9	4400	4483	22	
12337	1	013093	0330	0521	0700	32  42.47  S	10  53.87  E	4809	9	4795	4901	22	CFC

Notes 
1)	Position is reported for the time at the bottom of the cast
2)	Salinity, oxygen, silicate, phosphate, nitrate+nitrite were sampled for all bottles
3)	CFC denotes CFC-11, 12 and 113 and I denotes Iodine


XBT STATION LIST

	date			time, gmt						   depth, m		 Samples
Stn	Cast	mmddyy	start	bottom  end	    latitude	   longitude	uncwtr	ht off 	wire	max  p	 no    notes
													
1	1	122692	1444			45  01.15  S	57  30.29  W	3872	-99	-999	1833		T5
2	1	122792	0025			45  00.03  S	57  59.88  W	3206	-99	-999	1833		T5
3	1	122792	0501			44  59.52  S	58  29.94  W	2059	-99	-999	1833		T5
4	1	122792	0924			44  59.76  S	58  59.97  W	1558	-99	-999	1793		T5
5	1	122792	1304			44  59.81  S	59  14.85  W	1412	-99	-999	1431		T5
6	1	122792	1617			44  59.68  S	59  30.39  W	1222	-99	-999	1241		T5
7	1	122792	1937			44  59.22  S	59  45.30  W	1047	-99	-999	1063		T5
8	1	122792	2248			44  59.28  S	59  59.68  W	238	-99	-999	237		
9	1	122892	0719			44  57.28  S	59  33.73  W	1200	-99	-999	763		
10	1	122892	0826			44  58.87  S	59  18.64  W	1389	-99	-999	763		
11	1	122892	1229			44  57.48  S	58  57.00  W	1610	-99	-999	763		
14	1	122892	2011			44  59.49  S	58  23.29  W	2705	-99	-999	763		
15	1	122992	0032			44  59.40  S	58  10.75  W	3376	-99	-999	763		
16	1	122992	0111			44  59.72  S	58  01.56  W	3110	-99	-999	763		
17	1	122992	0753			44  58.68  S	57  36.32  W	4200	-99	-999	763		
18	1	122992	1404			45  00.70  S	57  11.82  W	4333	-99	-999	763		
19	1	122992	2011			45  00.97  S	56  44.38  W	5073	-99	-999	763		
20	1	123092	0408			45  01.40  S	56  07.95  W	5380	-99	-999	763		
21	1	123092	1510			45  00.75  S	55  07.73  W	5550	-99	-999	923		
22	1	123192	0020			44  58.77  S	54  14.43  W	5731	-99	-999	763		
23	1	123192	1236			44  59.45  S	53  14.63  W	5846	-99	-999	763		
24	1	123192	2244			44  54.19  S	52  15.82  W	5954	-99	-999	763		
25	1	010193	0727			45  02.18  S	51  15.42  W	5844	-99	-999	763		
26	1	010393	0119			45  02.76  S	50  17.40  W	5685	-99	-999	763		
27	1	010393	0909			45  00.68  S	49  15.04  W	5440	-99	-999	763		
28	1	010393	1717			45  00.19  S	48  12.44  W	5300	-99	-999	763		
29	1	010493	0049			44  59.50  S	47  14.55  W	5572	-99	-999	763		
30	1	010493	0833			44  59.57  S	46  14.03  W	5860	-99	-999	763		
31	1	010493	1600			45  00.22  S	45  14.28  W	5026	-99	-999	763		
32	1	010493	2313			44  59.68  S	44  15.05  W	4946	-99	-999	763		
33	1	010593	0626			45  00.00  S	43  15.00  W	4980	-99	-999	763		
34	1	010593	1551			44  59.83  S	42  11.74  W	5060	-99	-999	763		
35	1	010693	0325			44  58.86  S	41  12.86  W	4919	-99	-999	763		
36	1	010693	1238			44  58.62  S	40  05.32  W	4804	-99	-999	763		
37	1	010693	2024			44  59.05  S	39  14.19  W	5000	-99	-999	763		
38	1	010793	0424			44  59.00  S	38  11.16  W	4752	-99	-999	763		
39	1	010793	1207			45  01.85  S	37  13.04  W	5151	-99	-999	763		
40	1	010793	2233			44  59.11  S	36  15.31  W	5460	-99	-999	763		
41	1	010893	0616			44  59.75  S	35  14.73  W	5475	-99	-999	763		
42	1	010893	1406			44  59.89  S	34  16.15  W	5220	-99	-999	763		
43	1	010893	2302			44  56.96  S	33  15.18  W	5051	-99	-999	763		
44	1	010993	0657			45  00.48  S	32  14.31  W	5050	-99	-999	763		
45	1	010993	1424			44  59.78  S	31  13.73  W	5170	-99	-999	763		
46	1	010993	2321			44  56.24  S	30  15.39  W	4945	-99	-999	763		
49	1	011093	0801			45  00.27  S	29  10.79  W	4638	-99	-999	763		
50	1	011093	1847			44  59.53  S	28  14.82  W	4650	-99	-999	763		
51	1	011193	0236			45  00.69  S	27  12.41  W	4684	-99	-999	763		
52	1	011193	0936			44  58.39  S	26  14.51  W	4780	-99	-999	763		
53	1	011193	1657			44  59.70  S	25  17.14  W	-999	-99	-999	763		
54	1	011293	0013			45  01.56  S	24  14.14  W	4620	-99	-999	763		
55	1	011293	0649			44  58.98  S	23  15.42  W	4550	-99	-999	763		
56	1	011293	1410			45  00.38  S	22  13.35  W	3638	-99	-999	763		
57	1	011293	2207			45  00.06  S	21  15.61  W	4134	-99	-999	763		
58	1	011593	0237			44  59.22  S	20  13.85  W	3003	-99	-999	763		
59	1	011593	1136			44  59.68  S	19  08.56  W	3756	-99	-999	763		
60	1	011593	1851			45  00.33  S	18  00.20  W	3500	-99	-999	763		
61	1	011693	0215			44  59.82  S	16  45.68  W	3800	-99	-999	763		
62	1	011693	0934			44  58.69  S	15  36.62  W	1863	-99	-999	763		
63	1	011693	1601			44  47.01  S	14  31.47  W	3500	-99	-999	763		
64	1	011693	2318			44  20.51  S	13  30.92  W	3237	-99	-999	763		
65	1	011793	0614			43  54.69  S	12  32.06  W	3456	-99	-999	763		
66	1	011793	1308			43  27.77  S	11  33.83  W	3675	-99	-999	763		
67	1	011793	2022			43  01.46  S	10  34.51  W	3740	-99	-999	763		
68	1	011893	0333			42  35.99  S	9   36.56  W	3670	-99	-999	763		
69	1	011893	1056			42  08.83  S	8   37.80  W	3888	-99	-999	763		
70	1	011893	1808			41  42.77  S	7   42.57  W	3748	-99	-999	763		
71	1	011993	0115			41  20.75  S	6   49.00  W	3822	-99	-999	763		
72	1	011993	0920			40  57.97  S	6   00.83  W	3507	-99	-999	763		
73	1	011993	1056			40  48.49  S	5   39.99  W	800	-99	-999	763		
74	1	011993	1620			40  36.56  S	5   13.18  W	3804	-99	-999	763		
75	1	011993	2254			40  14.11  S	4   26.07  W	3559	-99	-999	763		
76	1	012093	0843			39  53.47  S	3   38.92  W	4327	-99	-999	763		
77	1	012093	1607			39  31.75  S	2   49.93  W	4400	-99	-999	763		
78	1	012093	2320			39  09.62  S	2   05.28  W	4520	-99	-999	763		
79	1	012193	0627			38  46.25  S	1   19.64  W	5306	-99	-999	763		
80	1	012193	1351			38  25.54  S	0   33.41  W	5800	-99	-999	763		
81	1	012193	2151			38  05.02  S	0   12.46  E	5147	-99	-999	763		
82	1	012293	0544			37  40.57  S	0   58.21  E	5250	-99	-999	763		
83	1	012293	1252			37  20.15  S	1   42.27  E	5050	-99	-999	763		
84	1	012293	2005			36  57.74  S	2   27.23  E	4901	-99	-999	763		
85	1	012393	0304			36  35.92  S	3   12.92  E	5200	-99	-999	763		
86	1	012393	0448			36  24.64  S	3   35.94  E	5185	-99	-999	811		T5
87	1	012393	0456			36  23.71  S	3   37.77  E	5185	-99	-999	763		
88	1	012393	1152			36  05.99  S	4   14.75  E	5086	-99	-999	763		
89	1	012393	1344			35  54.63  S	4   38.80  E	5086	-99	-999	763		
90	1	012393	2039			35  34.53  S	5   18.52  E	5196	-99	-999	763		
91	1	012393	2216			35  23.98  S	5   40.47  E	5218	-99	-999	763		
92	1	012493	0543			35  01.66  S	6   20.62  E	5350	-99	-999	763		
93	1	012493	0732			34  51.83  S	6   43.58  E	5230	-99	-999	763		
94	1	012493	1429			34  31.35  S	7   24.46  E	5128	-99	-999	763		
95	1	012493	1603			34  20.72  S	7   44.96  E	5197	-99	-999	763		
96	1	012493	2336			33  59.47  S	8   26.69  E	-999	-99	-999	763		
97	1	012593	0123			33  48.81  S	8   48.91  E	5047	-99	-999	763		
98	1	012593	1144			33  28.67  S	9   27.81  E	4968	-99	-999	763		
99	1	012593	1325			33  17.37  S	9   48.52  E	4994	-99	-999	1127		T5
100	1	012593	1335			33  16.45  S	9   50.40  E	4988	-99	-999	1832		T5
101	1	012593	2104			33  05.15  S	10  25.95  E	4800	-99	-999	1832		T5
102	1	012593	2240			33  07.38  S	10  44.54  E	4752	-99	-999	763		
103	1	012693	0002			33  09.10  S	11  03.09  E	4850	-99	-999	763		
104	1	012693	0203			33  11.80  S	11  30.40  E	4800	-99	-999	763		
105	1	012693	0400			33  14.49  S	11  54.79  E	-999	-99	-999	763		
106	1	012693	0559			33  16.76  S	12  18.73  E	-999	-99	-999	763		
108	1	012693	0802			33  18.47  S	12  43.31  E	4695	-99	-999	763		
109	1	012693	0957			33  20.03  S	13  06.57  E	-999	-99	-999	763		
110	1	012693	1204			33  22.71  S	13  32.09  E	5000	-99	-999	763		
111	1	012693	1400			33  25.48  S	13  56.13  E	-999	-99	-999	763		
112	1	012693	1559			33  27.22  S	14  21.13  E	4350	-99	-999	763		
113	1	012693	1800			33  29.98  S	14  46.22  E	4350	-99	-999	763		
114	1	012693	1959			33  32.10  S	15  11.23  E	-999	-99	-999	763		
115	1	012693	2204			33  34.89  S	15  36.97  E	3460	-99	-999	763		
116	1	012793	0006			33  37.37  S	16  00.34  E	3407	-99	-999	763		
117	1	012793	0200			33  40.10  S	16  25.13  E	3000	-99	-999	763		
118	1	012793	0400			33  42.98  S	16  54.44  E	1800	-99	-999	763		
119	1	012793	0600			33  45.64  S	17  25.31  E	530	-99	-999	599		
120	1	012793	1309			33  22.96  S	17  50.72  E	163	-99	-999	204		
121	1	012793	1500			33  01.59  S	17  35.71  E	250	-99	-999	305		
123	1	012793	1908			32  13.98  S	16  59.59  E	281	-99	-999	443		
124	1	012793	2259			31  28.25  S	16  28.93  E	363	-99	-999	405		
125	1	012893	0300			30  39.45  S	15  54.50  E	190	-99	-999	255		
126	1	012893	0732			30  21.31  S	15  21.89  E	280	-99	-999	340		
127	1	012893	0814			30  25.43  S	15  13.43  E	353	-99	-999	405		
128	1	012893	1036			30  32.45  S	15  01.53  E	750	-99	-999	763		
129	1	012893	1248			30  37.04  S	14  52.74  E	1288	-99	-999	1195		T5
130	1	012893	1552			30  44.33  S	14  39.77  E	1890	-99	-999	1216		T5
131	1	012893	1837			30  48.51  S	14  33.04  E	2250	-99	-999	1832		T5
132	1	012893	2308			31  02.28  S	14  05.94  E	2750	-99	-999	1260		T5
133	1	012993	0417			31  22.17  S	13  31.87  E	3250	-99	-999	1832		T5
134	1	012993	1104			31  46.48  S	12  44.51  E	3800	-99	-999	1207		T5
135	1	012993	1755			32  08.56  S	12  00.10  E	4160	-99	-999	1832		T5
136	1	013093	0112			32  30.27  S	11  16.38  E	4620	-99	-999	1832		T5

____________________________________________________________________________________________________________________________
____________________________________________________________________________________________________________________________

FIGURE LEGENDS

*All figures shown in PDF file

Figure 1:  The A11 cruise track defined by CTD/Rosette stations: Isobaths of 
           200m and 3000m are superimposed

Figure 2:  The location of 10 l water samples collected on cruise A11:  Depth is 
           in dbar.

Figure 3:  Silicate concentration versus potential temperature for A11 (*) and 
           SAVE 4 data:  both are in the Argentine basin and for the whole water 
           column: The inset, for the deepest levels, shows the small discrepancy 
           between the data sets.

Figure 4:  Dissolved oxygen concentration versus salinity for A11 (*) and SAVE 4 
           data:  both are in the Argentine basin and for the whole water column:   
           The inset, where the deepest levels form the left branch of the Y, 
           shows the small discrepancy between the data sets.

Figure 5:  Deep water collected on station 12240 from 2500m was used as quality 
           control for the nutrient measurements:  results are shown for the 
           last 50 stations of the cruise.

Figure 6:  A comparison of CFC-11 and CFC-12 data from (a) SAVE station 291 and 
           A11 station 12273 and (b) SAVE station 200 and A11 station 12295.

Figure 7:  Surface salinity (bold) and temperature (broken) on cruise A11:   The 
           cruise begins on the Argentine shelf, passes through the Falkland current 
           (day363), the Brazil current retroflection (day 365),traverses the 
           Subantarctic Zone until somewhere between day 386 and 390 it enters the 
           subtropical gyre:   The cruise ends in S.Africa

Figure 8:  Location of A11 and historical data:  Pluses, this cruise:  
             Crosses, SAVE leg 4:  
             Triangles, Atlantis II Cruise 107: 
             Inverted triangles, AJAX.

Figure 9:  This cruise: station averages of anomaly of salinity relative to 
           standard fits:  Horizontal axis: station number:  
                           Vertical axis:   salinity anomaly.

Figure 10: This cruise: sample minus CTD salinity residuals for all samples 
           flagged as good: Horizontal axis: pressure: Vertical axis: salinity 
           residual.

Figure 11: SAVE leg 4: station averages of anomaly of salinity relative to 
           standard fits: Horizontal axis: station number: Vertical axis: 
           salinity anomaly.

Figure 12: Atlantis II Cruise 107: station averages of anomaly of salinity 
           relative to standard fits: Horizontal axis: longitude: Vertical axis: 
           salinity anomaly.

Figure 13: This cruise: comparison of measured with predicted OXYTMP: Horizontal 
           axis: THETA: Vertical axis: measured minus predicted OXYTMP.

Figure 14: This cruise: station averages of anomaly of oxygen relative to standard 
           fits: Horizontal axis: station number: Vertical axis: oxygen anomaly 
           (µmol/l).

Figure 15: SAVE leg 4: station averages of anomaly of oxygen relative to 
           standard fits: 
                           Horizontal axis: station number: 
                           Vertical axis: oxygen anomaly (µmol/kg).

Figure 16: Atlantis II Cruise 107: station averages of anomaly of oxygen 
           relative to standard fits: 
                           Horizontal axis: longitude: 
                           Vertical axis: oxygen anomaly (µmol/l).

Figure 17: AJAX: station averages of anomaly of oxygen relative to standard  
           fits: 
                           Horizontal axis: latitude: 
                           Vertical axis: oxygen anomaly (µmol/l): 
           Intersects with A11 at 38 degrees south.

Figure 18: Station averages of nitrate anomaly relative to standard fits: 
                           Horizontal axis: station number or latitude: 
                           Vertical axis: nitrate anomaly (µmol/l): 
           (18a) - This cruise, (18b) - SAVE, (18c) - AJAX.

Figure 19: Station averages of silicate anomaly relative to standard fits: 
                           Horizontal axis: station number or latitude: 
                           Vertical axis: nitrate anomaly (µmol/l): 
           (19a) - This cruise, (19b) - SAVE, (19c) - AJAX.

Figure 20: Station averages of phosphate anomaly relative to standard fits: 
                           Horizontal axis: station number or latitude: 
                           Vertical axis: nitrate anomaly (µmol/l): 
           (20a) - This cruise, (20b) - SAVE, (20c) - AJAX.

________________________________________________________________________________
________________________________________________________________________________



CTD DATA QUALITY EVALUATION REPORT FOR WOCE CRUISE A11
(Bob Millard)
May 3, 1996

The overall potential temperature versus salinity plot of figure 1a shows a 
range of variation of potential temperature from slightly less than zero to 22 C 
while the salinity varies from 33.75 to 35.65 psu.  Figure 1b expands scales for 
lower layer and shows the two deep water masses, the colder and fresher 
Argentine Basin and the slightly warmer Cape Basin. A few noisy salinities are 
apparent in figure 1b.  The oxygens values range from 155 to 330 Umol/kg, as the 
potential temperature versus oxygen plots of figure 2 show.  Figures 1 and 2 
contain all of the two decibar observations plus the water sample salinities and 
oxygens.  To the resolution of these plots the temperature, salinity, and oxygen 
appear to be well behaved, except for a few noisy deep salinities. 

The water sample file salinity and oxygen data for both the CTD and bottle data 
are examined and the DQE quality word for these four parameters set in the 
second quality word of file A11.RCM.  The CTD oxygens in the bottle file were 
found on average to be 6.0 Umol/kg higher than the bottle oxygens and all CTD 
oxygens were flagged as questionable.  I agree with most of the other salinity 
and oxygen quality word assessments of the PI.  A summary of the modified 
quality words (except for CTD oxygen) is given in Appendix II.  A total of 83 
bottle observations had salinity or oxygen quality words adjusted.  Most of 
these occurred in the station group 12251 to 12255 where the CTD salinity was 
originally flagged as questionable by the PI but I found the CTD salinity 
observation differed from the bottle data by less than 3 standard deviations and 
in some cases by less than 0.001 psu (see Ds (ctd-ws) in Appendix II).

The evaluation of the CTD data of WOCE cruise A11 examines the following two CTD 
data sets: individual 2 decibar down-profile data (a total of 91 station files) 
and the subset of the up-profile CTD observations stored in the bottle file 
together with the water sample oxygens and salinities.  The cruise report (IOS 
Report # 234) covers the CTD calibration and processing methods including the 
the laboratory and in situ calibrations.  The need to adjust the CTD salinity on 
a station by station to match the bottle salinities is contrary to my experience 
with the Neil Brown Mark III CTD.  I did notice a few differences with how we 
correct conductivty at WHOI.  At WHOI the CTD conductivity model expands the 
cell geometry corrections around a deep water value (2.8 and 3000 dbars) which 
tends to force the fit to match in the deep water independent of mismatches in 
the conductivity cell geometry effects (alpha=-6.5E-6 & beta = 1.5 E-8).  We 
also allow another term in our fit, the conductivity bias.  That said, both the 
CTD salinity and oxygen data in the bottle file (A11.HYD) and the individual 2-
decibar down-profiles for WOCE cruise A11 are found to be well matched to water 
sample data with the exception of the CTD oxygen data in the bottle file which 
appears to have a systematic bias of about 6 Umol/kg.

To assess the CTD quality of the CTD data following data checks were carried out:

 o  Calibration checks: CTD and water sample Salinity and Oxygens
    Checks involve both the individual 2 decibar profiles and the bottle file 
    CTD subset. The calibration checks are divided into an assessments at all 
    depths and then only the deeper levels (defined as pressures greater than 
    1000 decibars). The calibration checks of salinity and oxygen involved 
    looking at the differences of the CTD minus the water sample values. Both 
    the down and up- profile CTD salinity and oxygen data were examined against 
    bottle values. The salinity differences presented are formed using the 
    bottle file CTD data while the oxygen differences presented are created by 
    interpolating the down-profile 2-decibar profiles CTD oxygens at the bottle 
    depths.

 o  Check for spurious salinity and oxygen values deep:
    An evaluation of the CTD salinity and oxygen noise levels with checks for 
    spurious data values. To check for spurious salinity and oxygen observations 
    in the 2 decibar CTD data the standard deviation (RMS) of the high-pass 
    filtered oxygen and salinity with wavelengths between 4 and 25 decibars is 
    summarized in the deep water depth ranges to the cast bottom. The RMS 
    scatter value is plotted versus station for several depth intervals from the 
    bottom to the surface.  Stations with a large scatter compared to the cruise 
    average are plotted versus pressure with suspect data values (values greater 
    than 5 standard deviations) identified on the plots.

 o  Vertical stability check.
    A check for density inversions provides additional information about 
    spurious salinity and/or temperature values particularly in the near surface 
    region where this method provides more a sensitive test than looking at the 
    high wave number salinity variability. The vertical gradient of potential 
    density (first difference) is calculated and checked for decreases in 
    density with depth exceeding one of two thresholds : (-0.0075 and -0.01 
    kg/m3). 


SALINITY CALIBRATION
The bottle file salinity differences are plotted versus station number, first at 
all pressures (figure 3a) and then the subset below 1000 decibars with a station 
average value indicated by the solid line in figure 3b.  The third panel, figure 
3c, is a plot of salinity differences versus pressure from 500 decibars to the 
bottom.   Figure 3c begins at 500 decibars to permit an expanded salinity range 
and indicates that the CTD salinity is well calibrated in the vertical.  Both 
plots versus station (3a and 3b) show the CTD salinity (conductivity) to be well 
matched to the water sample salts, the only evidence of a station off-set in 
figure 3b is for stations 12254, 12270 and 12319.  A look at the deep potential 
temperature- salinity for these and neighboring stations (not shown) does not 
reinforce these stations to be miscalibrated.   A histogram of salinity 
differences is shown for all pressures in figures 6c and below 1000 dbars in 
figure 6d.  The standard deviation for all salinity differences is 0.0047 psu. 
The standard deviation of the salinity differences below 1000 decibars is 0.0014 
psu which is a very tight scatter indicative of careful water sample salinity 
sampling and analysis.


OXYGEN CALIBRATION
Figures 4 a, b, c shows the interpolated down-profile oxygen differences versus 
station, overall and deep, and versus pressure.  The average oxygen difference 
below 1000 decibars in figure 4b shows that the 2 decibar oxygens are well 
matched to the water sample oxygens across the entire cruise.  The CTD oxygens 
below 1000 decibars for stations 12271-12273  and 12305-12307 may be from 1-2 
Umols/kg high and are checked further. The oxygen differences versus pressure in 
figure 4c indicates that the CTD oxygen is overestimated from 4500 decibars to 
the bottom by an amount of up to 5 Umol/kg at 6000 dbars.  Similar plots of the 
up-profile oxygen differences from the bottle file, shown in figures 5 a-b, 
indicate a systematic difference between the bottle file CTD and water sample 
oxygens with the CTD oxygens an average of about 6.0 Umol/kg greater than the 
water samples.  As noted earlier, all CTD oxygens in the bottle file are flagged 
as questionable in the second quality word.   A histogram of oxygen differences 
for all pressure levels figure 6a and below 1000 dbars in figure 6b.  The 
standard deviation using all of the good interpolated down-profile CTD oxygen 
differences is 3.31 Umol/kg (using the up-profile CTD oxygens yields a standard 
deviation of 2.99 umol/kg).  The oxygen differences below 1000 dbars are 
normally distributed with a standard deviation of 2.05 Umol/kg.

A series of waterfall plots consisting of down-profile CTD oxygen minus up water 
sample differences Dox= ( OXctd_dwn - WS) Umol/kg versus station are shown 
encompassing the 12273-12274 (figures 7a) and 12305-12307 (figure 7b).  There is 
no systematic depth off-set to either stations 12273-12274 or 12305-12307.  On 
the other hand, the deepest oxygen differences (greater than 4500 dbars) of 
stations 12260-12265 do show the CTD oxygen to be high.


SPURIOUS SALINITIES AND OXYGENS
The standard deviation of the high-pass filtered salinity (between vertical 
wavelengths of 4 and 25 decibars) from 3201 decibars to the bottom is shown in 
figure 8a. The bottom pressure is plotted versus station number in figure 8c. 
The average RMS CTD salinity scatter over the cruise of 0.00033 psu becomes as 
low as 0.0002 psu (stations 12268-12272).  The deep water salinity scatter is 
higher than the salinity noise level found on other cruises examined which have 
been observed to be as low as .00013 psu.  Figure 8a indicates that stations 
12292-12293 and stations 12306-12308 have elevated deep water noise levels.  
These stations are examined and contrasted with some better behaved profiles of 
salinity later.

The station averaged RMS oxygen scatter (noise level) for wavelengths between 4-
25 dbars is over twice as large as the best cruises examined (~0.1 Umol/kg).  
This may, in part, be due to a larger oxygen current quantizing although this 
can't be verified.  Stations 12286-12288, 12291 and 12313-12315 have abnormally 
large RMS oxygen scatters which carry over to the depth interval from 1199-3201 
dbars shown in figure 9b.  The stability of all 2 decibar CTD data is checked by 
looking at potential density differences that exceed one of two thresholds.  A 
plot of the pressure levels at which these instabilities occur (table I) is 
shown in figure 10 with potential density differences exceeding -0.0075 
kg/m3/dbar marked with an (x) and the subset of these data less than -0.01 
kg/m3/dbar marked with a (*).  A tabular listing of these 73 points with 
negative density gradients exceeding -.0075 kg/m3/dbar is given below.  The data 
set has 33 levels exceeding -.01 kg/m3/dbar.  For the most part, instabilities 
are in the shallow depths regions less than 500 decibars where the largest 
temperature and salinity gradients occur.


Some comments on individual or groups of stations

1: The salinities of stations 12291-12294 are overplotted and 12292-12294 show 
   an elevated deep water noise level as figure 11 indicates when contrasted 
   with figure 13.  In addition there are spurious questionable salinity 
   observations (x's) in stations 12292, 12293, & 12294.  None appear to flagged 
   in the quality word of the 2-dbars data files (see the quality word for the 
   salt spikes of station 12292 at 3971-3973 dbars or sta. 12294 at 3461 dbars, 
   all marked good). 

2: The salinities of stations 12306-12308 are overplotted and show an elevated 
   deep water noise level as figure 12 indicates when contrasted with figure 13.  
   In addition there are spurious bad observations (x's) in stations 12306 & 
   12308.  None appear to flagged in the quality word of the 2-dbars data files 
   (see the quality word for station 12306 at 3493 dbars, marked good).

3: The salinities of stations 12269-12272 are overplotted in figure 13 as a 
   control for deep water salinity variations for this data set.

4: The oxygens of stations 12286-12287 are overplotted and show an elevated 
   deep water noise level as figure 14 indicates when contrasted with figure 18.  
   There are bursts of noisy oxygens particularly for stations 12286 & 12287.  
   Stations 12285 seems free of excessive noise and 12288 also show fewer 
   problems pressure levels.

5: The oxygens of stations 12288-12291 are overplotted and show an elevated 
   deep water noise level as figure 15 indicates when contrasted again with 
   figure 18.  There are bursts of noisy oxygens in station 12291 while 
   variations of 12290 seems reasonable.
   
6: The oxygens of stations 12311-12315 are overplotted and all show bursts of 
   noisy oxygens as figure 16 indicates when contrasted with figure 18.

7: The oxygens of station 12317 are overplotted with stations 12316-12319 and 
   shows spikes of noisy oxygens as figure 17 indicates.

8: The oxygens of stations 12269-12272 are overplotted in figure 18 as a 
   control for deep water oxygens variations for this data set.


TABLE I

dsg/dp > -.0075 kg/m3/dbar
dsg/dp			station #	Prs dbars	salinity
 -1.6825525e-002	1.2252000e+004	1.5650000e+003	3.4766700e+001
 -1.4934576e-002	1.2252000e+004	1.5670000e+003	3.4716000e+001
 -7.5215734e-003	1.2252000e+004	1.5710000e+003	3.4707500e+001
 -8.9730034e-003	1.2254000e+004	1.9090000e+003	3.4810300e+001
 -7.5567868e-003	1.2255000e+004	2.3450000e+003	3.4783100e+001
 -9.8730225e-003	1.2256000e+004	2.5610000e+003	3.4772600e+001
 -1.5949690e-002	1.2258000e+004	9.3000000e+001	3.4857600e+001
 -1.2130733e-002	1.2258000e+004	1.3300000e+002	3.4938300e+001
 -1.2609297e-002	1.2258000e+004	1.3900000e+002	3.4924600e+001
 -8.8043772e-003	1.2258000e+004	1.8690000e+003	3.4663300e+001
 -1.0486886e-002	1.2258000e+004	1.8790000e+003	3.4645100e+001
 -2.4276438e-002	1.2259000e+004	1.1500000e+002	3.5164100e+001
 -1.7380894e-002	1.2259000e+004	1.2300000e+002	3.5334300e+001
 -8.4313404e-003	1.2259000e+004	1.6700000e+002	3.5076100e+001
 -8.7635833e-003	1.2259000e+004	2.3300000e+002	3.4497100e+001
 -9.4563893e-003	1.2259000e+004	2.3700000e+002	3.4442500e+001
 -9.9873559e-003	1.2261000e+004	2.2900000e+002	3.4284300e+001
 -1.9777770e-002	1.2261000e+004	2.3300000e+002	3.4254300e+001
 -2.1413379e-002	1.2262000e+004	4.9000000e+001	3.4114500e+001
 -2.8243981e-002	1.2262000e+004	5.3000000e+001	3.4137700e+001
 -7.6608833e-003	1.2262000e+004	6.5000000e+001	3.4126100e+001
 -9.4308111e-003	1.2262000e+004	7.3000000e+001	3.4149800e+001
 -9.2692607e-003	1.2262000e+004	9.0900000e+002	3.4415100e+001
 -9.2732815e-003	1.2262000e+004	9.1100000e+002	3.4395200e+001
 -7.7542689e-003	1.2262000e+004	2.0010000e+003	3.4761900e+001
 -1.6234888e-002	1.2262000e+004	2.0770000e+003	3.4758700e+001
 -8.1060643e-003	1.2265000e+004	5.1000000e+001	3.4784700e+001
 -9.6157972e-003	1.2272000e+004	2.2900000e+002	3.4240200e+001
 -1.0727370e-002	1.2275000e+004	8.8300000e+002	3.4440400e+001
 -2.4690527e-002	1.2277000e+004	8.7000000e+001	3.4541400e+001
 -8.7019074e-003	1.2277000e+004	1.4500000e+002	3.4654500e+001
 -8.1801374e-003	1.2278000e+004	4.9000000e+001	3.4259100e+001
 -2.1828669e-002	1.2278000e+004	1.3090000e+003	3.4552400e+001
 -1.1476531e-002	1.2279000e+004	8.5000000e+001	3.4497700e+001
 -1.7991091e-002	1.2280000e+004	9.7000000e+001	3.3998300e+001
 -8.9597959e-003	1.2282000e+004	1.8630000e+003	3.4758100e+001
 -2.1340326e-002	1.2286000e+004	7.1000000e+001	3.4276500e+001
 -1.0336119e-002	1.2286000e+004	1.3700000e+002	3.4369500e+001
 -9.2833570e-003	1.2286000e+004	1.6300000e+002	3.4295200e+001
 -1.7413396e-002	1.2292000e+004	6.3500000e+002	3.4177000e+001
 -2.6613984e-002	1.2294000e+004	1.8500000e+002	3.4405500e+001
 -8.3040160e-003	1.2294000e+004	1.9100000e+002	3.4450400e+001
 -8.4622237e-003	1.2294000e+004	3.8300000e+002	3.4178600e+001
 -8.5588970e-003	1.2296000e+004	2.1100000e+002	3.4354600e+001
 -3.2241057e-002	1.2298000e+004	1.0900000e+002	3.4019300e+001
 -2.7949113e-002	1.2298000e+004	1.1300000e+002	3.4033200e+001
 -9.3840991e-003	1.2298000e+004	1.4500000e+002	3.4153700e+001
 -1.8078311e-002	1.2302000e+004	9.9700000e+002	3.4266500e+001
 -8.5959918e-003	1.2305000e+004	4.5300000e+002	3.4358800e+001
 -9.0837387e-003	1.2307000e+004	1.1230000e+003	3.4290100e+001
 -1.5554406e-002	1.2308000e+004	8.5000000e+001	3.4682400e+001
 -8.0072034e-003	1.2308000e+004	3.2900000e+002	3.4603000e+001
 -9.0148257e-003	1.2310000e+004	2.8900000e+002	3.4445000e+001
 -7.5515126e-003	1.2311000e+004	4.9500000e+002	3.4301700e+001
 -1.4240604e-002	1.2312000e+004	8.9000000e+001	3.4771000e+001
 -9.2638822e-003	1.2312000e+004	1.2900000e+002	3.4742700e+001
 -8.9953691e-003	1.2312000e+004	2.8500000e+002	3.4653900e+001
 -9.2608014e-003	1.2312000e+004	3.5100000e+002	3.4539100e+001
 -7.8618847e-003	1.2314000e+004	4.4500000e+002	3.4546500e+001
 -9.7132557e-003	1.2315000e+004	1.0300000e+002	3.4959000e+001
 -9.2969453e-003	1.2316000e+004	6.9000000e+001	3.4942200e+001
 -9.8689572e-003	1.2316000e+004	1.4500000e+002	3.4835500e+001
 -1.2335594e-002	1.2316000e+004	2.0500000e+002	3.4847000e+001
 -1.2643058e-002	1.2316000e+004	2.2900000e+002	3.4805400e+001
 -9.7481726e-003	1.2316000e+004	2.8900000e+002	3.4829000e+001
 -1.0933894e-002	1.2323000e+004	1.0970000e+003	3.4302100e+001
 -8.3410129e-003	1.2325000e+004	3.0000000e+000	3.5632200e+001
 -8.4431894e-003	1.2325000e+004	8.5000000e+001	3.5562300e+001
 -2.9400095e-002	1.2325000e+004	8.3100000e+002	3.4416500e+001
 -1.3439053e-002	1.2325000e+004	8.5300000e+002	3.4402400e+001
 -1.6726372e-002	1.2325000e+004	8.8300000e+002	3.4316600e+001
 -8.5529223e-003	1.2325000e+004	1.1050000e+003	3.4426400e+001
 -1.0191833e-002	1.2326000e+004	8.5500000e+002	3.4393600e+001

SUBSET OF ABOVE THAT EXCEED dsg/dp > -.01 kg/m3/dbar

dsg/dp			station #	Prs dbars	salinity
 -1.6825525e-002	1.2252000e+004	1.5650000e+003	3.4766700e+001
 -1.4934576e-002	1.2252000e+004	1.5670000e+003	3.4716000e+001
 -1.5949690e-002	1.2258000e+004	9.3000000e+001	3.4857600e+001
 -1.2130733e-002	1.2258000e+004	1.3300000e+002	3.4938300e+001
 -1.2609297e-002	1.2258000e+004	1.3900000e+002	3.4924600e+001
 -1.0486886e-002	1.2258000e+004	1.8790000e+003	3.4645100e+001
 -2.4276438e-002	1.2259000e+004	1.1500000e+002	3.5164100e+001
 -1.7380894e-002	1.2259000e+004	1.2300000e+002	3.5334300e+001
 -1.9777770e-002	1.2261000e+004	2.3300000e+002	3.4254300e+001
 -2.1413379e-002	1.2262000e+004	4.9000000e+001	3.4114500e+001
 -2.8243981e-002	1.2262000e+004	5.3000000e+001	3.4137700e+001
 -1.6234888e-002	1.2262000e+004	2.0770000e+003	3.4758700e+001
 -1.0727370e-002	1.2275000e+004	8.8300000e+002	3.4440400e+001
 -2.4690527e-002	1.2277000e+004	8.7000000e+001	3.4541400e+001
 -2.1828669e-002	1.2278000e+004	1.3090000e+003	3.4552400e+001
 -1.1476531e-002	1.2279000e+004	8.5000000e+001	3.4497700e+001
 -1.7991091e-002	1.2280000e+004	9.7000000e+001	3.3998300e+001
 -2.1340326e-002	1.2286000e+004	7.1000000e+001	3.4276500e+001
 -1.0336119e-002	1.2286000e+004	1.3700000e+002	3.4369500e+001
 -1.7413396e-002	1.2292000e+004	6.3500000e+002	3.4177000e+001
 -2.6613984e-002	1.2294000e+004	1.8500000e+002	3.4405500e+001
 -3.2241057e-002	1.2298000e+004	1.0900000e+002	3.4019300e+001
 -2.7949113e-002	1.2298000e+004	1.1300000e+002	3.4033200e+001
 -1.8078311e-002	1.2302000e+004	9.9700000e+002	3.4266500e+001
 -1.5554406e-002	1.2308000e+004	8.5000000e+001	3.4682400e+001
 -1.4240604e-002	1.2312000e+004	8.9000000e+001	3.4771000e+001
 -1.2335594e-002	1.2316000e+004	2.0500000e+002	3.4847000e+001
 -1.2643058e-002	1.2316000e+004	2.2900000e+002	3.4805400e+001
 -1.0933894e-002	1.2323000e+004	1.0970000e+003	3.4302100e+001
 -2.9400095e-002	1.2325000e+004	8.3100000e+002	3.4416500e+001
 -1.3439053e-002	1.2325000e+004	8.5300000e+002	3.4402400e+001
 -1.6726372e-002	1.2325000e+004	8.8300000e+002	3.4316600e+001
 -1.0191833e-002	1.2326000e+004	8.5500000e+002	3.4393600e+001


APPENDIX II (CTD DQE)

CRUISE A11 CHANGES TO QUALITY WORD OF A1.HYD FILE

Below is a list of the bottles that have had a CTD or water sample salinity or 
oxygen flag changed. Only the first 5 field of the quality flags Qual1 and Qual2 
(DQE) are given as these were the only ones modified.  Note that all CTD oxygens 
have been flagged as questionable "3" as the CTD oxygens in the bottle file are 
systematically higher than the water samples by an average of 6.0 Umol/kg across 
the cruise.  On the other hand, the CTD oxygens in the individual 2 decibar CTD 
files do not show a systematic error with water sample oxygens.  Stations 12251 
through 12255 CTD salts flagged questionable but the magnitude of the CTD water 
sample salinity difference (Ds) for the most part are small (less than 3 
standard deviations) and don't substantiate flagging as questionable.  The first 
two observations of 12251 below have ctd salt flagged missing when CTD O2 is the 
missing parameter.  Sta. 12254 CTD up profile bottle data is systematically 
fresh except in deep water.  Station 12325 CTD salts are flagged "3" in the 
upper 1200 dbars when bottle differences are consistent with vertical structure. 

St.No.  Prs.	S_ws		Ox_ws		Ds(ctd-ws)	Dox(ctd-ws)	Qual1	Qual2
12251	   3.0	-9.0000		271.9000	43.0880		-280.9000	29299	23999  ctd o2=9
12251	  87.0	-9.0000		300.0000	43.1260		-309.0000	29299	23999  ctd o2=9
12251	 504.6	34.2346		235.5000	0.0000		6.9000		23222	22322
12251	 762.4	34.4159		186.8000	-0.0014		3.6000		23222	22322
12251	1011.6	34.5563		170.3000	-0.0006		4.7000		23222	22322
12251	1267.8	34.6339		167.3000	0.0008		5.5000		23222	22322
12251	1525.2	34.7052		175.1000	0.0005		5.4000		23222	22322
12251	1730.2	34.7571		189.6000	0.0017		4.8000		23222	22322
12251	1890.2	34.7321		182.4000	0.0025		4.7000		23222	22322
12252	  10.0	34.0907		280.9000	-0.0005		4.8000		23222	22322
12252	  55.6	34.1215		299.6000	0.0005		16.2000		23222	22322
12252	 105.1	34.1246		300.8000	0.0037		3.8000		23222	22322
12252	 154.9	34.1360		280.2000	-0.0011		10.4000		23222	22322
12252	 204.3	34.1391		278.2000	0.0002		2.3000		23222	22322
12252	 253.9	34.1503		268.7000	-0.0040		5.2000		23222	22322
12252	 353.8	34.1483		266.4000	0.0000		4.8000		23222	22322
12252	 498.9	34.2350		235.9000	0.0026		10.8000		23222	22322
12252	 757.6	34.4173		193.3000	0.0008		6.4000		23222	22322
12252	1017.6	34.5653		172.0000	-0.0008		6.4000		23222	22322
12252	1267.2	34.6370		169.7000	-0.0010		3.7000		23222	22322
12252	1512.9	34.6965		175.3000	-0.0029		6.2000		23222	22322
12252	1768.4	34.7526		190.2000	0.0022		2.3000		23222	22322
12252	2029.3	34.7628		192.7000	-0.0011		2.3000		23222	22322
12252	2291.5	34.7455		192.2000	-0.0003		5.6000		23222	22322
12252	2547.6	34.7459		191.9000	0.0008		5.6000		23222	22322
12252	2611.8	34.7465		192.6000	0.0007		5.8000		23222	22322
12252	2611.8	34.7471		191.5000	0.0001		6.9000		23222	22322
12253	  15.6	34.0895		285.6000	-0.0021		4.9000		23223	22323
12253	 105.2	34.1221		304.1000	-0.0008		5.5000		23223	22323
12253	 155.6	34.1350		289.0000	-0.0006		6.7000		23223	22323
12253	 206.9	34.1370		264.2000	-0.0029		20.3000		23223	22323
12253	 257.2	34.1348		333.4000	0.0021		-53.5000	23234	22324
12253	 356.3	34.1452		272.1000	-0.0024		-0.3000		23223	22323
12253	 504.8	34.2330		223.6000	0.0037		12.7000		23243	22323
12253	 760.8	34.4286		192.7000	0.0005		-9.0000		23223	22323
12253	1015.5	34.5679		158.2000	-0.0004		7.1000		23223	22323
12253	1271.5	34.6502		163.4000	-0.0005		4.0000		23223	22323
12253	1526.6	34.7203		180.3000	-0.0007		0.6000		23223	22323
12253	2035.9	34.7355		176.3000	0.0006		14.1000		23223	22323
12253	2289.4	34.7384		186.9000	-0.0038		9.7000		23223	22323
12253	2543.9	34.7398		199.9000	-0.0019		4.7000		23223	22323
12253	3052.8	34.7260		197.1000	0.0005		9.3000		23223	22323
12253	3136.0	34.7258		199.2000	0.0041		2.8000		23223	22323
12253	3136.0	34.7272		199.3000	0.0027		2.7000		23223	22323
12254	3453.7	34.7089		202.7000	0.0009		4.2000		23223	22323
12254	3453.7	34.7085		197.3000	0.0013		9.6000		23223	22323
12255	   9.8	34.0770		292.2000	0.0000		7.1000		23223	22323
12255	  55.8	34.1199		307.0000	0.0022		15.5000		23223	22323
12255	 106.2	34.1391		296.7000	-0.0013		-1.6000		23223	22323
12255	 155.7	34.1456		294.7000	-0.0017		8.0000		23223	22323
12255	 206.0	34.1432		287.9000	0.0002		6.0000		23223	22323
12255	 256.4	34.1470		282.4000	-0.0005		9.5000		23223	22323
12255	 355.7	34.1489		274.6000	0.0022		9.0000		23223	22323
12255	 507.4	34.2501		238.0000	0.0025		4.8000		23223	22323
12255	 763.8	34.3957		194.0000	-0.0009		10.2000		23223	22323
12255	1018.5	34.5243		178.0000	-0.0009		4.8000		23223	22323
12255	1273.3	34.6743		183.9000	-0.0010		3.6000		23223	22323
12255	1527.2	34.7510		194.8000	-0.0008		3.6000		23223	22323
12255	1781.0	34.7748		199.2000	-0.0014		10.4000		23223	22323
12255	2037.6	34.8212		214.6000	-0.0036		0.7000		23223	22323
12255	2548.5	34.7583		198.6000	-0.0028		5.0000		23223	22323
12255	3058.0	34.7368		201.9000	0.0000		6.0000		23223	22323
12255	3571.4	34.7072		207.4000	0.0007		5.2000		23223	22323
12255	4047.9	34.6789		217.7000	0.0006		7.3000		23223	22323
12263	1525.8	34.6011		177.0000	-0.0021		7.5000		22232	22322
12263	5590.2	34.6696		220.0000	0.0006		8.0000		22232	22322
12263	5889.8	34.6690		218.3000	0.0001		10.2000		22232	22322
12268	 510.0	34.1905		261.1000	0.0011		6.1000		22232	22322
12271	1271.1	34.5404		179.7000	-0.0012		6.3000		22232	22322
12271	2029.7	34.7901		203.0000	-0.0015		6.2000		22232	22322
12288	 357.7	34.1860		266.1000	0.0011		9.1000		22232	22322
12288	2281.4	34.7811		199.2000	-0.0019		6.4000		22232	22322
12318	 358.1	34.7762		221.8000	0.0078		3.6000		22232	22322
12325	   8.2	35.6719		221.1000	-0.0007		6.4000		23222	22322
12325	  53.5	35.5839		221.2000	-0.0054		12.8000		23222	22322
12325	 103.7	35.5527		200.1000	0.0009		0.5000		23222	22322
12325	 154.0	35.5267		199.8000	0.0081		0.8000		23222	22322
12325	 203.7	35.4352		197.0000	0.0055		4.0000		23222	22322
12325	 353.8	35.1547		215.8000	0.0063		6.8000		23222	22322
12325	 753.3	34.4864		198.9000	0.0043		12.2000		23222	22322
12325	1002.8	34.3861		196.6000	-0.0056		8.1000		23222	22322
12325	1239.0	34.4520		182.8000	0.0050		6.8000		23222	22322
12334	  53.9	35.5565		224.1000	-0.0059		9.3000		22232	22322

*Figures shown in PDF file.

________________________________________________________________________________
________________________________________________________________________________


NUTRIENTS DATA QUALITY EVALUATION REPORT FOR WOCE CRUISE A11
(J.C. Jennings and L. Gordon)
16 August 1996

Overall, the nutrient data appear to be of very good quality.  Most of the data 
points which were outside of regional nutrient/theta trends had been flagged by the 
data originator. Specific bottles which had problems noted by either the data 
originator or the WOCE DQE evaluator are listed below.

STATION		BOTTLE		PROBLEM					Q1	Q2
12257		25701		Low P					222	223
12257		25702		Low P					222	223
12257		25703		Low P					222	223
12257		25704		Low P					222	223
12257		25705		Low P					222	223
12259		25920		High Sil				333	333
12261		26112		N & P a bit high			222	233
12261		26119		P high					222	223
12262		26204		N high					222	232
12264		26424		High Sil				444	333
12284		28405		Low Sil					444	333
12283		28324		All nuts high				444	333
12288		28802		N low					222	232
12288		28804		N low					222	232
12288		28805		N low					222	232
12293		29320		N and P high				333	333
12302		30211		High P					222	223
12306		30619		Low P					223	223
12306		30618		Low P					223	223
12319		31906		High P					222	223
12319		31914		High P					222	223
12322		32224		Q1 flagged, theta high, could be real	444	333
12323		32324		Sil and P a bit high			444	333
12329		32905		Sil high, O2 low			333	333
12331		33109		Sil high				333	333

INPUT FILE: A11.JCJ
THE DATE TODAY IS: 21-AUG-96

STNNBR	CASTNO	SAMPNO	CTDPRS	 SILCAT	   NO2+NO3	PHSPHT	QUALT1	QUALT2
12257	1	25705	3528.0				2.03	~~2	~~3
12257	1	25704	4043.8				2.07	~~2	~~3
12257	1	25703	4558.6				2.10	~~2	~~3
12257	1	25701	5397.3				2.10	~~2	~~3
12261	1	26112	2553.3		   28.96	1.92	~22	~33
12262	1	26204	5099.3		   33.92		~2~	~3~
12264	1	26424	11.7	  2.75	   10.66	0.66	444	333
12283	1	28324	16.3	  14.72	   21.09	1.38	444	333
12284	1	28405	3018.2	  76.66				4~~	3~~
12302	1	30211	760.9				2.12	~~2	~~3
12319	1	31906	3045.5				1.78	~~2	~~3
12322	1	32224	11.5	  3.35	   4.03		0.39	444	333
12323	1	32324	10.6	  2.46	   3.64		0.37	444	333

________________________________________________________________________________
________________________________________________________________________________


WHPO-SIO DATA PROCESSING NOTES

Date      Contact        Data Type       Data Status Summary
--------  -------------  --------------  ---------------------------------------
06/23/94  Saunders       CTD             Submitted
          
07/01/94  Piola          CTD & BTL       DQE Contacted; no CFCs
          
07/26/94  Saunders       SUM & BTL       Submitted; no CFCs
          
08/25/95  Saunders       CTD & BTL       Data are Final; no CFCs yet
          
03/27/96  Jennings-Jr.   NUTs            Agreed to do DQE
          
04/22/96  Millard        CTD/S/O         DQE Report rcvd @ WHPO
          
05/03/96  Millard        CTD/S/O         REVISED DQE Report rcvd @ WHPO
          
08/16/96  Jennings-Jr.   NUTs            DQE Report to WHPO
          
09/17/96  Saunders       NUTs            DQE Report to PI
          
11/18/96  Saunders       CFCs            Submitted
          
11/19/96  Saunders       CTD/NUTs        PI OK'd DQE Changes
          
05/23/97  Smythe-Wright  CFCs            Data are Public
          
08/13/97  Saunders       SUM             file on web is incomplete
          35 stas. missing from SUM file on SAC
          
09/12/97  Saunders       SUM/BTL         Corrections needed on SAC webs
          
09/16/97  Saunders       SUM/BTL         new files sent to Saunders
          ftp'd a tar format archive with a README file that should explain 
          all of the particulars, except for the fact that there is another 
          tarfile within that contains CTD stations ---> 12292, 12293, 12294  
          12306 12308 and 12317.
          
10/28/97  WHPO Incoming  BTL & SUM       Data Sent to SAC
          

Date      Contact        Data Type       Data Status Summary
--------  -------------  --------------  ---------------------------------------
04/25/98  Smythe-Wright  CFCs            Data are Public; problems with CFC-12
          Thank you for your enquiry about A11 CFC data.  I have no 
          objection to Ricardo Locarnini having the data and for them to be 
          made fully public. However I must stress that the CFC-12 data 
          required considerable reworking due to contamination and so I 
          cannot say that I am fully confident with the CFC-12 data set.  
          Also as a result of some work I have been doing lately I fear that 
          and error in one of my original spreadsheets may have been 
          perpetuated into the final data set sent to you.  This means that 
          SOME but not all of the deep CFC-12 data are askew by a factor of 
          up to 1.43.  The error seems have originated in converting from 
          the SIO 86 to 93 scale but rather than using the factor for CFC-12 
          the value for CFC-113 has sneaked in instead. Because the values 
          are so small the error may have been overlooked. I think it is 
          just a case of a wrong cell identifier in a spreadsheet and so 
          hopefully it can be cleared up soon.
          
08/13/98  Sutherland     NO2+NO3         Problems with Quality Flags
          The original quality code for every bottle for Nitrate+Nitrite is 9, 
          while there are hundreds of non -9.0 data points.
          
10/12/98  Anderson       NO2+NO3         Data are OK; see note to S. Sutherland
          Re the A11 NO3+NO2 quality flags.   Only parameters with  ******* 
          under them have quality flags and in this case NO3+NO2 is the 7th 
          parameter so underscored and the corresponding quality flag isn't 
          always 9.  
          
06/06/00  Gould          O18/O16/Iodine  data and doc Submitted
          I have got some delta oxygen-18 and iodine species data from the 
          WOCE A11 cruise (Discovery 199).
          
          I have attached all the files to this email. The iodine data are 
          very few and so probably very easy to merge manually perhaps. So 
          I've attached these as BODC received them (12256_12288.xls and 
          methods_iodine.doc).
          
          I have created a WHPO format file for the oxygen-18 data 
          (DI199.O18.TXT). I have also included the original file 
          (a11_o18.txt) that we received from the data originators incase 
          there were bottle misfires (as I've said before, we average 
          these).  I know your database currently has individual bottles, 
          they were supplied by the data originator's.
          

Date      Contact        Data Type       Data Status Summary
--------  -------------  --------------  ---------------------------------------
06/28/00  Huynh          DOC             Website Updated
          txt version w/ iodine update added to website
          
11/21/00  Uribe          DOC             Preliminary version located
          File was found in incoming directory under whp_reports. The 
          directory was zipped, files were separated and placed under proper 
          cruise. All of them were doc files received 1997 August 15th.
          
03/21/01  Uribe          CTD/BTL/SUM     Expocodes updated in online files
          
          Expocodes for bottle and sum were modified.  Expocodes in all ctd 
          files have been edited to match the underscored expocode in the 
          sum and bottle files. New files were zipped and replaced existing 
          ctd files online. Old files were moved to original directory. 
          
06/20/01  Uribe          BTL             Website Updated; Exchange File online
          Bottle file in exchange format has been linked to website.
          
06/21/01  Uribe          CTD/BTL         Exchange files modified/online
          exchange bottle file name in directory and index file was modified 
          to lower case.
          CTD exchange files were put online.
          
12/19/01  Hajrasuliha    CTD             Internal DQE completed
          Created *check.txt file. could not produce .ps file. 
          
09/15/03  Kappa          DOC             Updated Cruise Report
          o  Added these data processing notes
          o  Updated all figures
          o  Updated pdf internal links
          o  Minor reformatting

          

