ORNL/CDIAC-125
                                                         NDP-074
 
    CARBON DIOXIDE, HYDROGRAPHIC, AND CHEMICAL DATA OBTAINED
     DURING THE R/V HESPERIDES CRUISE IN THE ATLANTIC OCEAN
          (WOCE SECTION A5, JULY 14 - AUGUST 15, 1992)
                                
                         Contributed by
      Frank J. Millero,* Sara Fiol,* Douglas M. Campbell,* 
                     and Gregorio Parrilla**
                                
      *Rosenstiel School of Marine and Atmospheric Science
                       University of Miami
                         Miami, Florida
                                
               **Instituto Espanol de Oceanografa
                     Madrid, 28002, Spain  
                                
                                 
       Prepared by Linda J. Allison and Alexander Kozyr***
           Carbon Dioxide Information Analysis Center
                  Oak Ridge National Laboratory
                      Oak Ridge, Tennessee
                                
          ***Energy, Environment, and Resources Center
                   The University of Tennessee
                      Knoxville, Tennessee
                                
                                
                 Environmental Sciences Division
                       Publication No. 4988
                                
                                
                    Date Published:  June 2000
                                
                                
                        Prepared for the
                 Environmental Sciences Division
         Office of Biological and Environmental Research
                    U.S. Department of Energy
     Budget Activity Numbers KP 12 04 01 0 and KP 12 02 03 0
                                
                         Prepared by the
           Carbon Dioxide Information Analysis Center
                  OAK RIDGE NATIONAL LABORATORY
                 Oak Ridge, Tennessee 37831-6335
                           managed by
                        UT-BATTELLE, LLC
                             for the
                    U.S. DEPARTMENT OF ENERGY
                under contract DE-AC05-00OR22725


ACKNOWLEDGMENTS

   The authors wish to acknowledge the National Oceanographic and Atmospheric
Administration, the Oceanographic Section of the National Science Foundation,
the U.S. Department of Energy, and the Office of Naval Research for supporting
this study.


ACRONYMS

14C        radiocarbon
ADCP       acoustic Doppler current profiler
ASCII      American Standard Code for Information Interchange
CDIAC      Carbon Dioxide Information Analysis Center
CEAB       El Centro de Estudios Avanzados de Blanes
CFC        chlorofluorocarbon
CO2        carbon dioxide
CRM        certified reference material
CTD        conductivity, temperature, and depth sensor
DOE        U.S. Department of Energy
emf        electromotive force
FCMLP      Facultad de Ciencias del Mar
fCO2       fugacity of CO2 
FTP        file transfer protocol
GC         gas chromatography
GMT        Greenwich Mean Time
GO         General Oceanics
GPS        global positioning system
IEO        Instituto Espanol de Oceanografia
IIM        Instituto de Investigaciones Marinas
IPO        WOCE International Program Office
IR         infrared
JGOFS      Joint Global Ocean Flux Study
LDEO       Lamont-Doherty Earth Observatory
NBIS       Neil Brown Instruments Systems
NDP        numeric data package
nm         nautical mile
NOAA       National Oceanic and Atmospheric Administration
PSS        practical salinity scale     
QA         quality assurance
RSMAS      Rosenstiel School of Marine and Atmospheric Science
RTD        resistive temperature device
R/V        research vessel
SIO        Scripps Institution of Oceanography
TALK       total alkalinity
TCO2       total carbon dioxide
UPC        Universidad Politecnica de Cataluna
URL        universal resource locator
WCRP       World Climate Research Program
WHOI       Woods Hole Oceanographic Institution
WHPO       WOCE Hydrographic Program Office
WOCE       World Ocean Circulation Experiment


ABSTRACT

Millero, F. J., S. Fiol, D. M. Campbell, G. Parrilla. 2000.  Carbon Dioxide,
   Hydrographic, and Chemical Data Obtained During the R/V  Hesperides 
   Cruise in the Atlantic Ocean (WOCE Section A5, July 14 - August 15, 1992),
   L. J. Allison and A. Kozyr (eds.). ORNL/CDIAC-125, NDP-074.  Carbon   
   Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S.    
   Department of Energy, Oak Ridge, Tennessee, U.S.A.  51 pp.

  This data documentation discusses the procedures and methods used to measure
total carbon dioxide (TCO2), total alkalinity (TALK), and pH at hydrographic
stations during the R/V Hesperides oceanographic cruise in the Atlantic Ocean
(Section A5).  Conducted as part of the World Ocean Circulation Experiment
(WOCE), the cruise began in Cadiz, Spain, on July 14, 1992, and ended in
Miami, Florida, on August 15, 1992.  Measurements made along WOCE Section A5
included CTD pressure, temperature, salinity, and oxygen; and bottle salinity,
oxygen, phosphate, nitrate, nitrite, silicate, TCO2, TALK, and pH.
   The TALK, TCO2, and pH were determined from titrations of seawater collected
at 33 stations.  The titration systems for measuring TALK and TCO2 were
calibrated in the laboratory with certified reference materials (CRMs) before
the cruise to ensure traceable results. Standard reference seawater provided 
by Andrew Dickson of Scripps Institution of Oceanography (SIO) was used at 
sea to monitor the performance of the titration systems.  The results agree
with the laboratory results to 2 mol/kg for TALK and 1 mol/kg for TCO2.  
The titration systems used to measure pH were calibrated with TRIS seawater 
buffers prepared in the laboratory and measured with an H2, Pt/AgCl, Ag 
electrode.  The initial electromotive force (emf) of the titrations was used 
to determine the pH.  The values of pH are thought to be reliable to 0.01 and 
are internally consistent with the measured values of TALK and TCO2 to 
7 mol/kg.  The measured carbon dioxide system parameters have been used to 
calculate the in situ values of the fugacity of CO2 (fCO2) for the surface 
water.  The surface results are briefly discussed.
   WOCE section A5 is located at 24.5 N along the meridional overturn in 
the Atlantic Ocean.  The maximum heat transfer in the North Atlantic Ocean 
occurs at 24 N; warming in the ocean at this latitude goes down to 
3000 m.  This section has been studied for a number of years and thus can be 
used to examine the changes that have occurred in the North Atlantic deep 
waters.  This section has also been studied in the past using inverse methods 
to look at the movement of CO2 to and from the North Atlantic.  
  The WOCE Section A5 hydrographic and carbonate data set is available free of 
charge as a numeric data package (NDP) from the Carbon Dioxide Information 
Analysis Center.  The NDP consists of two oceanographic data files, two 
FORTRAN 77 programs, a documentation file, and this printed 
report, which describes the contents and format of all files as well as the 
procedures and methods used to obtain the data.  Instructions on how to access 
the data are provided.



Keywords: Carbon dioxide; World Ocean Circulation Experiment; North Atlantic
Ocean; hydrographic measurements; alkalinity; carbon cycle



                           PART 1:
                           
                          OVERVIEW
                          

                   1.  BACKGROUND INFORMATION

   There is currently much interest in understanding the inorganic carbon
dioxide (CO2) system in the oceans. This is due to the increasing atmospheric
concentration of CO2 enhancing the earth-atmosphere system's natural 
greenhouse effect and potentially affecting the earth's climate.  Approximately
40% of the CO2 added to the atmosphere as a result of the burning of fossil
fuels is thought to be in turn absorbed by the oceans.  The flux of
carbon dioxide across the air-sea interface is controlled by the difference in
the partial pressure of CO2 in the atmosphere and in the surface waters.  Once
the CO2 is in solution it can equilibrate with the bicarbonate and carbonate
ions.  The carbonate ion concentration in the oceans controls the rate of
precipitation and dissolution of calcium carbonate (CaCO3) in the oceans.  The
carbon dioxide system can be characterized by measuring two of the four
measurable parameters [pH, the fugacity of CO2 (fCO2), the total carbon
dioxide (TCO2), and the total alkalinity (TALK)].  The other parameters can be
calculated using thermodynamic relations.
   To learn more about the role of the world ocean in climate dynamics,
several large ocean experiments have been conducted.  The World Ocean
Circulation Experiment (WOCE) is the largest such experiment ever attempted.
A major component of the World Climate Research Program (WCRP), WOCE brings
together scientists from more than 30 nations.  Although TCO2 is not an
official WOCE measurement, carbonate chemists are participating in the WOCE
cruises as part of the Joint Global Ocean Flux Study (JGOFS) to measure the
components of the carbon dioxide system in the oceans.  These studies are
being sponsored in the United States by the U.S. Department of Energy (DOE)
and the National Oceanographic and Atmospheric Administration (NOAA).  The
carbon dioxide system parameters measured, in order of  preference, are the
TCO2, TALK, and pH.  Preferred analytical methods are coulometery for TCO2,
titration for TALK, spectroscopy for pH, and infrared (IR) or gas
chromatography (GC) for fCO2.  Because coulometry and IR or GC systems to 
measure fCO2 and TCO2 were not available on the R/V Hesperides cruise, 
and because only one berth was available, the
TALK, TCO2,  and pH were determined by titration.  Although this is not ideal,
it was believed that some reasonably precise data were better than no data.
   The present report gives the results of carbonate measurements made during
the 32 days of the expedition of the R/V Hesperides along WOCE section A5
(along 24.5 N).

                  2.  DESCRIPTION OF THE EXPEDITION

2.1 R/V Hesperides Cruise Information

 Ship name              R/V Hesperides
 Expedition code        29HE06/1
 WOCE Section           A5
 Location               Cadiz, Spain; to Santa Cruz de Tenerife, Canary
                          Islands; to Las Palmas de Gran Canaria, Canary 
                          Islands; to Miami, Florida, U.S.A.
 Dates                  July 14 - August 15, 1992
 Chief scientist        Gregorio Parrilla

Parameters measured      Institution       Principal Investigator

CTD*                         IEO               G. Parrilla
                             WHOI              H. Bryden
Salinity                     IEO               R. Molina
Oxygen                       IEO               J. Escanez
Nutrients                    CEAB              A. Cruzado
Chlorofluorocarbons (CFCs)   LDEO              W. Smethie
pH, TALK, TCO2               IIM               A. Rios
                             RSMAS             F. Millero
Calcium                      IIM               G. Roson
Chlorophyll pigments         IEO               J. Garcia Braun
                             CEAB              Z. Velazquez
Primary productivity         IEO               J. Garcia Braun
Aluminum                     FCMLP             J. Hernandez
Radiocarbon (14C)            LDEO              W. Broecker
ADCP**                       UPC               M. Garcia

Participating Institutions

CEAB                     El Centro de Estudios Avanzados de Blanes 
FCMLP                    Facultad de Ciencias del Mar
IEO                      Instituto Espanol de Oceanografia
IIM                      Instituto de Investigaciones Marinas
LDEO                     Lamont-Doherty Earth Observatory
RSMAS                    Rosenstiel School of Marine and Atmospheric Science
UPC                      Universidad Politecnica de Cataluna
WHOI                     Woods Hole Oceanographic Institution

____________________________________________________

*Conductivity, temperature, and depth sensor.
**Acoustic Doppler current profiler.


2.2 Brief Cruise Summary

   According to the WOCE Implementation Plan, the cruise line for WOCE Section
A5 was to be located at 24 N.  Since two oceanographic sections had previously
been made (1957 and 1981) around 24.5 N (Roemmich and Wunsch 1985), the WOCE
International Program Office (IPO) agreed to a request by the chief scientist
to move WOCE Section A5 to this latitude for data comparison purposes.
   The R/V Hesperides departed from Cadiz, Spain, on July 14, 1992.  The 
cruise track and station locations are shown in Fig. 1 in the hard copy report. 
During the cruise, 118 CTD/rosette stations were occupied.  Six stations were
made to test the CTD and rosette.  Four test stations  were occupied before the
ship arrived at Santa Cruz de Tenerife, Canary Islands, on July 17.  The ship 
left Tenerife on July 18 and occupied two more test stations before arriving
at Las Palmas de Gran Canaria. (The data from the six test stations are not 
included in this NDP.)  The ship departed from Las Palmas in the early hours of
July 20 and arrived at the first station of WOCE Section A5 the same day.  After
101 stations were made, the ship arrived at the Bahamas on August 14 and WOCE 
Section A5 was completed.  During the next day, 11 additional hydrographic 
stations were collected in the Straits of Florida and the cruise was concluded.
For navigation and placement of stations, a global positioning system (GPS)
was used.
   Because of ship time constraints, station spacing was determined as follows:
The first six stations of WOCE Section A5 were located at the 50-, 100-, 150-,
1500-, 2000-, and 2500-m isobaths and were about 18 nautical miles (nm) apart;
from there to the 4000-m depth (Station 12), the distance between stations was
about 23 nm.  From Station 12 to the eastern limits of the Mid-Atlantic Ridge,
the stations were separated by 36 nm.  Across the Ridge, the separation was 32
nm.  From the western limits of the Mid-Atlantic Ridge to the 5000-m isobath
near the Bahamas, stations were again separated by 36 nm.  Stations close to
the Bahamas were separated by less than 30 nm.  The stations across the
Straits of Florida were occupied every 5 nm.
   Near the Bahamas, the expedition deviated slightly from the planned
cruise track in order to cross the continental slope perpendicularly to
the direction of the isobaths and to obtain a clear crossing of the Deep
Western Boundary Current.
   The ADCP and a thermosalinograph recorded continuously during the entire
cruise.  Wind  information was recorded every hour.  Basic sampling equipment
included three CTDs and a 24-bottle General Oceanics (GO) rosette system
equipped with 10- or 12-L water sampling bottles.
   The TCO2 concentration was determined in 660 samples from 33 of the 112 CTD
stations occupied during the cruise.
   At the end of the cruise the ship was checked for tritium and 14C
contamination by the Tritium Laboratory of the University of Miami.


                3.  DESCRIPTION OF VARIABLES AND METHODS

3.1. Hydrographic Measurements
      
   The R/V Hesperides carried three CTDs, two belonging to the Instituto
Espanol de Oceanografia (IEO) and one belonging to Woods Hole Oceanographic
Institution (WHOI).  The two EG&G/NBIS Mark IIIb CTD underwater units belonging
to IEO were each equipped with pressure, temperature, conductivity, and 
polygraphic oxygen sensors and were used throughout the cruise.  Each CTD was 
configured identically with the same data scan length, variables, and scanning 
rate of 31.25 Hz.  A detailed description of the Mark IIIb CTD can be found in
Brown and Morrison (1978).  Both instruments were modified at WHOI to add a 
titanium pressure sensor with a separately digitized resistive temperature 
device (RTD) (Millard et al. 1993).  The third EG&G/NBIS Mark IIIb CTD was 
provided by WHOI but was not used during this expedition.  A General Oceanics
(GO) rosette fitted with 24 10- or 12-L Niskin bottles was used with the CTD for 
collecting water samples.  The GO rosette bottles were mounted approximately 
0.5 m above the CTD sensors.  The conductivity and oxygen sensors were also 
calibrated at sea using the analysis of the water samples collected at each 
station.  The depths of the sampling stations were based on classical standard 
depths, although they varied on a station by station basis according to 
participants' needs to sample a particular layer, provided there was no 
impairment of the in situ calibration activities.  Because of delays inflicted 
by Hurricane Andrew on the equipment shipment from Miami to Woods Hole, the 
post-cruise calibrations were not performed on the CTD sensors until December. 
   All water sample measurements for bottle salinity and bottle oxygen
were made in a constant temperature laboratory soon after each cast was
completed.  Water samples for salinity were collected from the Niskin bottles
in Ocean Scientific International glass bottles, and the measurements were
made within 24 hours after the station was finished.  In total, 2,294 samples
were measured.  The bottle salinities were measured with a Guildline Autosal
Model 8400A salinometer.  The manufacturer claims a precision of 0.0002 and an
accuracy of 0.003 when the instrument is operated at a temperature between +4
and -2 C of ambient temperature.  All salinity measurements were made in a
temperature-controlled laboratory about 1-3C below that of the salinometer
water bath.
   Bottle oxygen determinations were carried out following the Winkler method
and using the reagents prepared according to Carpenter (1965).  On this
cruise, the modified Carpenter's equation as given by Culberson et al. (1991)
was used.  The endpoint of tritration was determined visually using starch as
the indicator.  Reagents were dispensed with 0- to 2-ml capacity Dispensette
glass and teflon dispensers from BRAND GMBH & CO.  The dispensers had a
certified accuracy of < or =0.6% and a coefficient of variation of < or =0.1%.
The tips of the dispensers were lengthened up to 6 cm with thin plastic tubing 
to avoid the precipitation of manganese hydroxide in the neck of sample flasks. 
Titration was done with a Metrohm Dosimat E.412 automatic burette.
   Samples for nutrient analyses (silicate, nitrate, nitrite, and phosphate)
were collected in 150-mL acid-rinsed polythene flasks directly from the Niskin
bottles, following the protocol established by the WOCE Hydrographic Program. 
Analyses were performed onboard with a four-channel Skalar, Inc. segmented
flow autoanalyzer.  Analyses were carried out immediately without any
treatment of the samples.  When necessary, samples were kept in the cold room
(unfrozen and never for more than 10 hours) without additives.  The analytical
techniques followed were those described by Whitledge et al. (1981) with minor
modifications to adapt them to the particular conditions of the instrument
used and concentration ranges observed.  Primary standards were prepared at
the beginning and in the middle of the cruise following Whitledge et al.
(1981).  Secondary standards were prepared every two days and preserved with
several drops of chloroform in the refrigerator.  Running standards of various
concentrations were prepared daily, and calibration curves were run at the
beginning of each  session.  Standards were interleaved with unknown samples
in order to provide a measure of analytical stability.  Whenever changes in
sensitivity were noticed (particularly in the case of nitrate), the standards
allowed for a correction to be applied.  All concentrations were referred to
double distilled water prepared by reverse osmosis.  No seawater sample has
ever given a concentration negative with respect to this double distilled
water.  Phosphate analyses were corrected for the change in absorbance as a
result of the salinity effect.  Surface seawater was used as a carrier and,
except for silicate, it always showed the minimum concentrations in the water
column.  Silicate concentrations below the surface were often found to be
lower than those at the surface and very close to the values given by double
distilled water.  Replicate samples were analyzed at various depths.
   More detailed information on hydrographic measurements can be found at
http://whpo.ucsd.edu/data/onetime/atlantic/a05/index.htm.

3.2  Carbon Measurements 

   The total alkalinity (TALK), total carbon dioxide (TCO2), and pH were
determined from titrations of seawater collected at 33 stations.  The
titration systems were calibrated with Dickson standard seawater before and
during the cruise.  The pH was determined from the initial emf reading
relative to TRIS buffers.  The results for Dickson samples agree with
laboratory spectroscopic measurements for pH to 0.005. 

3.2.1  Methods for Measurement and Computation

   Three titration systems (Thurmond and Millero 1982) were used to
determine the TALK.  Each system consisted of a Metrohm 655 Dosimat titrator
and an Orion 720A pH meter that was operated by a personal computer (PC)
(Millero et al. 1993a).  The titration was made by adding HCl to the seawater
past the carbonic acid end point (pH ~ or = 3.5).  The
solutions were contained in water-jacketed cells (230 cm3) controlled to a
constant temperature of 25C with a Forma temperature controller.  The
computer program used to perform the titration was developed in the Rosenstiel
School of Marine and Atmospheric Science (RSMAS) laboratory using RS232
interfaces.  A BASIC program was used to run the titration and record the
volume of the added acid and the emf of the electrode system.  A typical
titration recorded the emf after the readings became stable (0.09 mV) and
added enough acid to change the voltage to a preassigned value (13 mV).  A
full titration (25 points) took about 20 minutes.  Using two systems, a
24-bottle cast could be analyzed in 4-5 hours. 
   The electrode systems used to measure the emf of the sample during a
titration consisted of a ROSS glass pH electrode and an Orion double-junction
reference electrode.  A number of electrodes were screened to select those to
be used in the titration systems.  Electrodes with non-Nerstian behavior
(slopes 1.0 mV different from theoretical) in acidic solutions were discarded. 
The reliability of a glass-reference electrode pair was determined by
titrating 0.7-M NaCl solutions with HCl, by using seawater buffers (Ramette et
al. 1977), and by determining the TALK of TCO2 CRMs provided by Dr. Andrew
Dickson of SIO.  The titrations of 0.7-M NaCl solutions were used to evaluate
the electrode slope in acidic solutions (pH > or = 2 and < or = 4).  Seawater 
buffers (Millero et al. 1993b) were used to evaluate the electrode slope near 
a pH of 8.  The resulting experimental electrode slopes found for the cells 
used in the present study are given in Table 1.  The slopes near a pH of 8 were
lower than the theoretical value (59.16 mV), whereas the slopes near a pH of 3
were near the theoretical value.  The electrodes were also evaluated by 
determining the TALK, TCO2, and pH of TCO2 CRMs.  The results are given in 
Table 2.  The results indicate that precise values of TALK (1.8 mol/kg), 
TCO2 (5 mol/kg), and pH (0.005) can be obtained on weighed samples of 
seawater. The precision of the pH measurements for a given electrode (0.003) 
is better than the average deviation from the mean (0.005). 


     Table 1.  Summary of the calibration results for the cells at 25C
____________________________________________________________________________

 Cell   Volume    Electrode slope    Standard  Electrode slope    Standard
         (cm3)   buffer calibration deviation  acid calibration   deviation
____________________________________________________________________________
 1.00    212.59         58.40         -0.80        59.00            -0.20
 6.00    218.50         57.50         -1.70        59.60             0.40
 7.00    234.29         58.00         -1.20        59.50             0.30
____________________________________________________________________________



   Table 2.  Titrations of certified reference materials (S = 33.82) in the    
                                  laboratory
____________________________________________________________________________

   Seawater            TALK            TCO2              pH             N
____________________________________________________________________________

  Batch #12         2227.0  1.8     2002.0  5       7.930  0.01       13
                                                     7.942  0.0005*
  Standard          2226.6             1984          7.940  0.0002**
____________________________________________________________________________

     *Calculated from the initial emf using TRIS buffer calibration.
     **From spectroscopic measurements.


   The HCl acid solutions used throughout the cruise were standardized in
the laboratory.  The approximately 0.25-M HCl solutions used contained 0.45-M
NaCl to yield an ionic strength equivalent to average seawater (0.7 M). 
Approximately 20 liters of acid were made up in the laboratory.  The
calibrated acid was stored in 500 cm3 bottles for use at sea.  The acid was
standardized by titrating weighed amounts of Na2CO3 and TRIS dissolved in
0.7-M NaCl solution.  The blanks in the 0.7-M NaCl solutions were determined
by using coulometery and by titrations of the NaCl solutions with and without
added Na2CO3 and TRIS.  The TCO2 in the blanks and carbonate solutions was
measured daily by a UIC coulometer.  The coulometer was calibrated using CO2
gas loops and CRMs.  The blanks of the titrations of TRIS were obtained by
extrapolation to zero-added salt.  The alkalinity blanks in the NaCl were
generally about 14  1 M.  The concentrations of the standard acids obtained
from Na2CO3 and TRIS were in good agreement (Millero et al. 1993a).  
   The volumes of the cells used at sea were determined in the laboratory
by weighing the cells filled with water.  The density of water at the
temperature of the measurements (25C) was calculated from the international
equation of state of seawater (Millero and Poisson 1981).  The nominal volumes
of all the cells was about 230 cm3 and the values were determined to 0.03 cm3. 
The reliability of the volumes was assessed by comparing the values of TALK
obtained for standard solutions with open and closed cells. 
   A FORTRAN computer program has been developed to calculate the CO2
parameters (pHsws, emf, TALK, TCO2, and pK1*) in Na2CO3 and seawater
solutions.  These programs are patterned after those developed by Dickson
(1984).  This program requires an input of the concentration of the acid, the
volume of the cell, the salinity, the temperature of analysis, volume of added
HCl (VHCl), and the corresponding measured values of the emf.  To obtain a
reliable TALK from a full titration, at least 25 points have to be collected. 
The precision of the fit is less than 0.4 mol/kg when pK1* is allowed to vary,
and 1.5 mol/kg when pK1* is fixed.  This titration program has been compared
with the titration programs used by others (Dickson 1981; C. Goyet, WHOI,
personal communication, 1992; Bradshaw and Brewer 1988), and the values of
TALK agree to within 1 mol/kg.  Copies of the titration and calculation
programs used are available upon request from Frank J. Millero 
(fmillero@rsmas.miami.edu).

3.2.2  Calibrations

   Before the cruise, a number of titrations were made on CRMs (#12) in the
laboratory.  The laboratory titration results for TALK, TCO2, and pH are given
in Table 2 along with the assigned TCO2 and the pH measured relative to TRIS 
buffers (Dickson 1993) and spectrophotometrically (Byrne and Breland 1989;
Robert-Baldo et al. 1985; Millero et al. 1993b; Clayton and Byrne 1993).  It
should be pointed out that the values of pH are on the seawater scale defined
by Dickson (1984):
     
           pHsws = -log[H+]sws = -log{[H+] + [HSO4-] + [HF]}                (1)

The precision in the values of TALK (2 mol/kg), TCO2 (5 mol/kg), and pH
(0.005) was quite good.  The titration values of TCO2 were 18  4 mol/kg higher
than the values assigned and measured by coulometery.  The titration values of
pH (7.93  0.01) were 0.01 lower than the values measured by spectrophotometric
methods (7.940  0.002) and using seawater buffers (Millero et al. 1993b).  The
differences in pH and TCO2 are caused by the non-ideal behavior of the
electrodes near a pH of 8 (Millero et al. 1993a).  Calibration of the
electrodes using TRIS seawater buffers yielded a pH of 7.942  0.005 from the
initial emf readings of the titration.  These results are in excellent
agreement with the spectrophotometrically determined pH and show a lower
standard error than the values determined from the titrations.
   The program used to calculate the TCO2 parameters assumed that the
electrodes would respond to a change in pH with an ideal slope of 59.2 mV at
25C as determined from the Nernst equation.  The slopes of the electrodes
using buffers and titrating with HCl frequently gave non-ideal behavior.  The
parameters produced by varying this slope indicated (Millero et al. 1993a)
that the deviations resulting from these changes were much greater for TCO2
than for TALK.  Errors of 1.0 mV in the slope yielded differences in TALK and
TCO2, respectively, of 2.1 and 22.8 mol/kg when the pK1* was also allowed to
vary (Millero et al. 1993a).  The values of TALK were not strongly affected by
the behavior of the electrodes.  The values of TCO2 and pH determined for the
CRMs with the buffer-derived slope (58.4) were in good agreement with the
correct values (pH = 7.935 and TCO2 = 1984 mol/kg).  These calculations
indicated that the deviations in the TCO2 derived from titration were a result
of errors in the slope of the electrode, and not a result of unknown
protolytes (Bradshaw and Brewer 1988).  If the slope determined from the
buffers was used, the titrations yielded reliable values of pH, TALK and TCO2. 
This fact was used to make sure that the field titration measurements yielded
the most reliable values of pH and TCO2.
   During the cruise, the electrodes in each titration system were
calibrated with TRIS seawater buffers (Millero 1986) of known pHsws (8.057)
determined with a H2, Pt/AgCl, Ag electrode (Millero et al. 1993b). 
Titrations of CRMs (#12) were also made during the cruise.  The results are
given in Table 3.  The average values, TALK = 2229  7 mol/kg, TCO2 = 
1984  6 mol/kg, and pH = 7.944  0.01, are in good agreement with the 
laboratory results.  The deviations are larger at sea than obtained in the 
laboratory (Table 2) but indicate that the titration systems performed well
throughout the cruise.  The large errors are related to problems in reproducing
the volume in the glass cells.  Presently, a plastic cell with a more 
reproducible volume is used, making it possible to reproduce the CRMs to 
2 mol/kg for TALK, to 3 mol/kg for TCO2, and to 0.005 for pH 
(Millero et al. 1993a).


Table 3.  Titrations of certified reference materials at sea (Batch #12)
 ________________________________________________________________________

Cell            TALK        TCO2         pH                 N
_________________________________________________________________________

1              2229  6     1983  5    7.937  0.009*        14
6              2230  8     1981  8    7.944  0.021*         5
7              2229  6     1984  8    7.948  0.013*        12
_________________________________________________________________________
Average        2229  7     1984  6    7.942  0.014         31
_________________________________________________________________________
Standard       2226.6**      1984***      7.940****
_________________________________________________________________________
     *Calculated from the initial emf using TRIS buffer calibration.
     **Certified value from weighted titrations.
     ***Certified value from manometric extraction technique.
     ****Results obtained in the laboratory using spectrophotometric methods


3.2.3  Results

   The cruise track of the R/V Hesperides is shown in Fig. 1 in the hard copy
report.  A summary of the 33 TCO2 stations that were sampled during the cruise
is given in Table 4.  Based upon the CRM calibrations at sea, the accuracy of 
the measured parameters is estimated to be 7 mol/kg for TALK and TCO2 and 
0.02 for pH.  The thermodynamic consistency of the measurements can be shown 
by comparing the calculated values of pH (7.944), TALK (2334 mol/kg), and TCO2 
(1984 mol/kg) using the constants of Roy et al. (1993) with the measured values
(Table 3).  The agreement is quite good.  The values of TALK, TCO, and pH as a 
function of depth for all of the samples are shown in Figs. 3-5 in the hard copy
report.  Plots of the surface properties of the waters sampled are shown in 
Figs. 6-8 in the hard copy report. 
   The temperature increases from 22C near the Spanish coast to 27C off the
coast of Florida.  The salinities go through a maximum (37.5) between stations
20 to 50 (30 to 45 W).  The surface values of TALK (Fig. 7 in hard copy) follow
this trend.  The TCO2 is fairly constant from stations 1 to 60 (2108  10 mol/kg)
and decreases off the coast of Florida to 2020 mol/kg.  The pH at 25C increases
from 8.05 off the coast of Spain to about 8.12 off the coast of Florida
(average pH = 8.05  0.03).  The values of TALK and TCO2 normalized to 
S = 35 are shown in Fig. 8 (in hard copy).  The average normalized TALK
is 2293  4 mol/kg for the surface waters, whereas the average normalized 
TCO2 is 1970  20 mol/kg.  The in situ fugacities of CO2 (fCO2) calculated from 
the measured values of TALK and TCO2 are shown in Fig. 8 (in hard copy).  From these
calculations, the surface waters (fCO2 = 402  15 atm) are supersaturated with CO2 
(delta fCO2 = 42  15 atm ) for all the surface waters. 



Table 4.  Summary of carbonate system stations occupied during the cruise
__________________________________________________________________________

    Station      Latitude      Longitude      Depth      Date 
     no.          ( N)          ( W)         (m)
__________________________________________________________________________     
     1            2429'         1558'          53     7/20/1992
     3            2429'         1629'         575     7/20/1992
     8            2429'         1820'        2736     7/20/1992
    11            2430'         1935'        3393     7/22/1992
    13            2430'         2040'        4186     7/23/1992
    15            2430'         2159'        4705     7/24/1992
    18            2430'         2359'        5149     7/24/1992
    21            2430'         2559'        5403     7/25/1992
    25            2430'         2839'        5723     7/26/1992
    28            2430'         3038'        5745     7/27/1992
    31            2430'         3240'        6426     7/28/1992
    34            2430'         3440'        5354     7/29/1992
    37            2430'         3640'        5008     7/30/1992
    40            2430'         3840'        4580     7/30/1992
    43            2430'         4035'        4551     7/31/1992
    46            2430'         4220'        4430     8/01/1992
    49            2430'         4404'        4182     8/01/1992
    53            2430'         4624'        3518     8/02/1992
    57            2430'         4844'        4541     8/03/1992
    60            2430'         5029'        4975     8/04/1992
    62            2430'         5139'        4888     8/04/1992
    64            2430'         5250'        5231     8/05/1992
    67            2430'         5440'        6275     8/05/1992
    70            2430'         5640'        6024     8/06/1992
    73            2430'         5839'        6145     8/07/1992
    77            2430'         6119'        5965     8/08/1992
    81            2430'         6359'        5858     8/09/1992
    84            2430'         6559'        5832     8/10/1992
    82            2430'         6800'        5805     8/11/1992
    90            2430'         7000'        5626     8/12/1992
    93            2430'         7159'        5571     8/12/1992
    97            2500'         7420'        4994     8/13/1992
   101            2430'         7531'        1040     8/14/1992
____________________________________________________________________________


 
           4.  DATA CHECKS AND PROCESSING PERFORMED BY CDIAC

   An important part of the NDP process at the Carbon Dioxide Information
Analysis Center (CDIAC) involves the quality assurance (QA) of data before
distribution.  Data received at CDIAC are rarely in a condition that would
permit immediate distribution, regardless of the source.  To guarantee data of
the highest possible quality, CDIAC conducts extensive QA reviews that involve
examining the data for completeness, reasonableness, and accuracy.  The QA
process is a critical component in the value-added concept of supplying
accurate, usable data for researchers. 
   The following information summarizes the data processing and QA checks
performed by CDIAC on the carbon-related, hydrographic, and chemicaldata 
obtained during the R/V Hesperides cruise along WOCE Section A5 in the 
Atlantic Ocean.

1.   Carbon-related data and hydrographic measurements were provided to CDIAC
by Frank Millero (RSMAS).  The final hydrographic and chemical measurements 
and the station information files were provided by the WOCE Hydrographic 
Program Office (WHPO) after quality evaluation. A FORTRAN 77 retrieval code 
was written and used to merge and reformat all data files.

2.   To check for obvious outliers, all data were plotted using a
PLOTNEST.C program written by Stewart C. Sutherland (Lamont-Doherty Earth
Observatory).  The program plots a series of nested profiles, using the
station number as an offset; the first station is defined at the beginning,
and subsequent stations are offset by a fixed interval (Figs. 9-11 in hard copy).
Several outliers were identified and marked with the quality flags of 3 
(questionable measurement) or 4 (bad measurement) (see File Descriptions in 
Section 7 of this documentation).

3.   To identify noisy data and possible systematic, methodological errors,
property-property plots for all parameters were generated (Fig. 12 in hard copy), 
carefully examined, and compared with plots from previous expeditions in the 
Atlantic Ocean.

4.   All variables were checked for values exceeding physical limits, such as
sampling depth values greater than the given bottom depths.

5.   Dates, times, and coordinates were checked for bogus values (e.g.,
values of MONTH < 1 or > 12; DAY < 1 or > 31; YEAR < or > 1992; TIME < 0000 or
> 2400; LAT < 20.000 or > 30.000; and LONG < -90.000 or > 0.000).

6.   Station locations (latitudes and longitudes) and sampling times were
examined for consistency with maps and cruise information supplied by Frank J.
Millero of RSMAS.

7.   The designation for missing values, given as -9.0 in the original files,
was changed to -999.9 for consistency with other oceanographic datasets.


               5.  HOW TO OBTAIN THE DATA AND DOCUMENTATION

   This database (NDP-074) is available free of charge from CDIAC.  The 
complete documentation and data can be obtained from the CDIAC oceanographic 
Web site (http://cdiac.esd.ornl.gov/oceans/doc.html), through CDIAC's online 
ordering system (http://cdiac.esd.ornl.gov/pns/how_order.html), or by 
contacting CDIAC.
   The data are also available from CDIAC's anonymous file transfer protocol 
(FTP) area via the Internet.  Please note that your computer needs to have FTP 
software loaded on it (this is built in to most newer operating systems).  Use 
the following commands to obtain the database.

     ftp cdiac.esd.ornl.gov  or  >ftp 128.219.24.36
     Login: anonymous or ftp
     Password: your e-mail address
     ftp> cd pub/ndp074/
     ftp> dir
     ftp> mget (files)
     ftp> quit

  

Contact information:

 Carbon Dioxide Information Analysis Center
 Oak Ridge National Laboratory
 P.O. Box 2008
 Oak Ridge, Tennessee 37831-6335
 U.S.A.

 Telephone:  865-574-3645
 Telefax:  865-574-2232

 E-mail:  cdiac@ornl.gov

 Internet:  http://cdiac.esd.ornl.gov/


                          6. REFERENCES
          
Bradshaw, A. L., and P. G. Brewer.  1988.  High precision measurements of
alkalinity and total carbon dioxide in seawater by potentiometric titration-1. 
Presence of unknown protolyte(s).  Marine Chemistry 23:69-86.
         
Brown, N., and G. Morrison.  1978.  WHOI/Brown Conductivity, Temperature, and
Depth Microprofiler.   WHOI Technical Report #78-23.  Woods Hole Oceanographic
Institution, Woods Hole, Mass., U.S.A.
     
Byrne, R. H., and J. A. Breland.  1989.  High precision multiwavelength pH
determinations in seawater using cresol red.  Deep-Sea Research 36:803-10.

Carpenter, J. H.  1965.  The Chesapeake Bay Institute technique for the
Winkler dissolved oxygen titration.  Limnology and Oceanography 10:141-3.

Clayton T., and R. H. Byrne.  1993.  Spectrophotometric seawater pH
measurements:  total hydrogen ion concentration scale calibration of m-cresol
purple and at-sea results.  Deep-Sea Research 40:2115-29.

Culberson, C. H., G. Knapp, M. C. Stalcup, R. T. Williams, and F. Zemlyak. 
1991.  A comparison of methods for the determination of dissolved oxygen in
seawater.  Report No. WHPO 91-2.  WOCE Hydrographic Program Office.  Woods
Hole Oceanographic Institution, Woods Hole, Mass., U.S.A.

Dickson, A. G.  1981.  An exact definition of total alkalinity and a procedure
for the estimation of alkalinity and total CO2 from titration data.  Deep-Sea
Research 28:609-23.

Dickson, A. G.  1984.  pH scales and proton-transfer reactions in saline media
such as seawater.  Geochemica et Cosmochemica Acta 48:2299-2308.

Dickson A. G.  1993.  pH buffers for sea water media based on the total
hydrogen ion concentration scale.  Deep-Sea Research 40:107-18.

Millard, R., G. Bond, and J. Toole.  1993.  Implementation of a titanium
strain-gauge pressure transducer for CTD applications.  Deep-Sea Research
40(5):1009-21.

Millero, F. J.  1986.  The pH of estuarine waters.  Limnology and Oceanography
31:839-847.

Millero, F. J., and A. Poisson.  1981.  International one-atmosphere equation
of state of seawater.  Deep-Sea Research 28:625-629.

Millero F. J., J.-Z. Zhang, K. Lee, and D. M. Campbell.  1993a.  Titration
alkalinity of seawater.   Marine Chemistry 44:153-66.

Millero F. J., J.-Z. Zhang, S. Fiol, S. Sotolongo, R. N. Roy, K. Lee, and S.
Mane.  1993b.  The use of buffers to measure the pH of seawater.  Marine
Chemistry 44:143-52.

Ramette, R. W., C. H. Culberson, and R. G. Bates.  1977.  Acid base properties
of tris (hydrolymethyl) aminomethane (tris) buffers in seawater from 5 to 40C. 
Analytical Chemistry 49:867-70.

Robert-Baldo, G., M. J. Morris, and R. H. Byrne.  1985.  Spectrophotometric
determination of seawater pH using phenol red.  Analytical Chemistry
57:2564-67.

Roemmich, D., and C. Wunsch.  1985.  Two transatlantic sections: Meridional
circulation and heat flux in the subtropical North Atlantic Ocean.  Deep-Sea
Research 32(6):619-64.

Roy R. N., L. N. Roy, K. M. Vogel, C. P. Moore, T. Pearson, C. E. Good, F. J.
Millero, and D. M. Campbell.  1993.  Determination of the ionization constants
of carbonic acid in seawater.  Marine Chemistry 44:249-68.

Thurmond, V. L., and F. J. Millero.  1982.  Ionization of carbonic acid in
sodium chloride solutions at 25C.  Journal of Solution Chemistry 
11(7):447-56.

Whitledge, T. E., S. C. Malloy, C. J. Patton, and C. D. Wirick.  1981. 
Automated analysis of sea water.  BNL-51398.  Brookhaven National Laboratory,
U. S. Department of Energy, Upton, New York, U.S.A.




                             PART 2:
                             
                 CONTENT AND FORMAT OF DATA FILES
                 
                 
                    7.  FILE DESCRIPTIONS
 
This section describes the content and format of each of the five files that
comprise this NDP (see Table 5).  Because CDIAC distributes the data set in
several ways, (e.g., via anonymous FTP and on floppy diskette), each of the
five files is referenced by both an ASCII file name, which is given in
lowercase, bold-faced type (e.g., ndp074.txt) and a file number.  The
remainder of this section describes (or lists, where appropriate) the contents
of each file.


               Table 5.  Content, size, and format of data files
_________________________________________________________________________________
File number, name,                                     Logical    File size
and description                                        records     in bytes
_________________________________________________________________________________

1.  ndp074.txt:                                          1,144      57,492  
    a detailed description of the cruise, listings 
    of the two provided FORTRAN 77 programs, and 
    descriptions of the content and format of
    the two oceanographic files.

2.  stainv.for:                                             44       1,331
    a FORTRAN 77 program to read and print 
    a5sta.dat (file 4)

3.  a5dat.for:                                              53       2,070
    a FORTRAN 77 program to read and print
     a5.dat (file 5) 

4.  a5sta.dat:                                             123       9,593
    a listing of the station locations, sampling
    dates, and sounding bottom depths for each 
    of the 112 stations of WOCE Section A5.

5.  a5.dat:                                              2,487     401,604
    hydrographic, carbon dioxide, and chemical 
    data from the 112 stations occupied on WOCE
    Section A5.
                                                      ________________________

    Total                                                 3,851    472,090   
___________________________________________________________________________________ 




7.1 ndp074.txt (File 1)
 
   This file contains a detailed description of the data set, listings of 
the two FORTRAN 77 programs used to read and print the data, and descriptions
of the content and format of the two oceanographic data files.  This file 
exists primarily for the benefit of individuals who acquire this database as
machine-readable data files from CDIAC.  


7.2 stainv.for (File 2)
 
   This file contains a FORTRAN 77 program to read and print a5sta.dat (File 4).
The following is a listing of this program.  For additional information 
regarding variable definitions, variable lengths, variable types, units, and 
codes, please see the description for a5sta.dat in Sect. 7.4.


c*****************************************************************
c* This is a Fortran 77 retrieval code to read and format the    *       
c* station inventory file named a5sta.dat (File 4).              * 
c***************************************************************** 

c*Defines variables*

       INTEGER  stat, cast, depth
       REAL latdcm, londcm 
       CHARACTER expo*8, sect*3, date*10, time*4
       OPEN (unit=1, file='a5sta.dat')
       OPEN (unit=2, file='a5stat.dat')
       write (2, 5)

c*Writes out column labels*

 5     format (4X, 'STATION INVENTORY: R/V HESPERIDES, WOCE A5',/,
     1 4X,'EXPOCODE',1X,'SECT',1X,'STNBR',2X,'CAST',
     2 9X,'DATE',2X,'TIME',3X,'LATITUDE',3X,'LONGITUDE',2X,
     3 'DEPTH',/)

c*Sets up a loop to read and format all the data in the file*

       read (1, 6)
 6     format (//////////)

 7     CONTINUE    
       read (1, 10, end=999) expo, sect, stat, cast, date, time,
     1 latdcm, londcm, depth

 10    format (A12, 2X, A3, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 4X,
     1 F7.3, 4X, F8.3, 3X, I4)
 
       write (2, 20) expo, sect, stat, cast, date, time,
     1 latdcm, londcm, depth

 20    format (A12, 2X, A3, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 4X,
     1 F7.3, 4X, F8.3, 3X, I4)

       GOTO 7
 999   close(unit=5)    
       close(unit=2)
       stop
       end


7.3 a5dat.for (File 3)

   This file contains a FORTRAN 77 program to read and print a5.dat (File 5).
The following is a listing of this program.  For additional information 
regarding variable definitions, variable lengths, variable types, units, 
and codes, please see the description for a5.dat in Sect. 7.5.

c****************************************************************
c* FORTRAN 77 data retrieval routine to read and print the      *       
c* file named "a5.dat" (File 5).                                *
c****************************************************************
       CHARACTER qualt*12
       INTEGER sta, cast, samp, bot 
       REAL pre, ctdtmp, ctdsal, ctdoxy, theta, sal, oxy, silca
       REAL nitrat, nitrit, phspht, talk, tcarb, ph
       OPEN (unit=1, file='a5.dat')
       OPEN (unit=2, file='a5data.dat')
       write (2, 5)

c*Writes out column labels* 

 5     format (2X,'STNNBR',2X,'CASTNO',2X,'SAMPNO',2X,'BTLNBR',2X,
     1 'CTDPRS',2X,'CTDTMP',2X,'CTDSAL',3X,'CTDOXY',3X,'THETA',4X,
     2 'SALNTY',2X,'OXYGEN',2X,'SILCAT',2X,'NITRAT',2X,'NITRIT',2X,
     3 'PHSPHT',2X,'ALKALI',2X,'TCARBN',7X,'PH',7X,'QUALT1',/,
     5 36X,'DBAR',2X,'ITS-90',2X,'PSS-78',2X,'UMOL/KG',2X,'ITS-90',
     6 4X,'PSS-78',1X,'UMOL/KG',1X,6('UMOL/KG',1X),1X,'@25_DEG',12X,
     8 '*',/,25X,'*******',17X,2('*******',2X),9X,'*******',1X,
     8 7('*******',1X),1X,'*******',12X,'*')

c*Sets up a loop to read and format all the data in the file*

       read (1, 6)
 6     format (//////////////)

 7     CONTINUE    
       read (1, 10, end=999) sta, cast, samp, bot, pre, ctdtmp,
     1 ctdsal, ctdoxy, theta, sal, oxy, silca, nitrat, nitrit,
     2 phspht, talk, tcarb, ph, qualt

 10    format (5X, I3, 7X, I1, 6X, I2, 6X, I2, 1X, F7.1, 1X, F7.4,
     1 1X, F7.4, 1X, F8.3, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2,
     2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 1X, F7.1, 1X, F8.3, 
     3 1X, A12)

       write (2, 20) sta, cast, samp, bot, pre, ctdtmp,
     1 ctdsal, ctdoxy, theta, sal, oxy, silca, nitrat, nitrit,
     2 phspht, talk, tcarb, ph, qualt

 20    format (5X, I3, 7X, I1, 6X, I2, 6X, I2, 1X, F7.1, 1X, F7.4,
     1 1X, F7.4, 1X, F8.3, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2,
     2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 1X, F7.1, 1X, F8.3, 
     3 1X, A12)

       GOTO 7
 999   close(unit=1)    
       close(unit=2)
       stop
       end



7.4 a5sta.dat (File 4)
 
   This file provides station inventory information for each of the 112 stations
occupied during the R/V Hesperides cruise along WOCE Section A5.  Each line of
the file contains an expocode (expedition code unique to each cruise), section
number, station number, cast number, sampling date (month/day/year), sampling 
time, latitude, longitude, and sounding depth.  The file is sorted by station 
number and can be read by using the following FORTRAN 77 code (contained in 
stainv.for, File 2):

       INTEGER  stat, cast, depth
       REAL latdcm, londcm 
       CHARACTER expo*8, sect*3, date*10, time*4

       read (1, 10, end=999) expo, sect, stat, cast, date, time,
     1 latdcm, londcm, depth

 10    format (A12, 2X, A3, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 4X,
     1 F7.3, 4X, F8.3, 3X, I4)

Stated in tabular form, the contents include the following: 

_____________________________________________________________________________

Variable      Variable            Variable     Starting        Ending 
               type                width        column         column
_____________________________________________________________________________

expo         Character              12            1              12
sect         Character               3           15              17
stat         Numeric                 3           21              23
cast         Numeric                 1           29              29
date         Character              10           33              42
time         Character               4           45              48
latdcm       Numeric                 7           53              59
londcm       Numeric                 8           64              71
depth        Numeric                 4           75              78
_____________________________________________________________________________



The variables are defined as follows:

expo          is the unique expedition code of the cruise;

sect          is the WOCE section number;

stat          is the station number;

cast          is the cast number;

date          is the sampling date (month/day/year);

time          is the sampling time [Greenwich mean time (GMT)];

latdcm        is the latitude of the station (in decimal degrees; negative 
              values indicate the Southern Hemisphere);

londcm        is the longitude of the station (in decimal degrees; negative 
              values indicate the Western Hemisphere);

depth         is the sounding depth of the station (in meters).



7.5 a5.dat (File 5)
 
   This file provides hydrographic, carbon dioxide, and chemical data for the 
112 stations occupied during the R/V Hesperides cruise along WOCE Section A5. 
Each line consists of a station number, cast number, sample number, bottle
number, CTD pressure, CTD temperature, CTD salinity, CTD oxygen, potential
temperature, bottle salinity, oxygen, silicate, nitrate, nitrite, phosphate,
total alkalinity, total CO2, pH at 25C, and data-quality flags.  The file is
sorted by station number and pressure and can be read by using the following
FORTRAN 77 code (contained in a5dat.for, File 3):
  
       CHARACTER qualt*12
       INTEGER sta, cast, samp, bot
       REAL pre, ctdtmp, ctdsal, ctdoxy, theta, sal, oxy, silca
       REAL nitrat, nitrit, phspht, talk, tcarb, ph 

       read (1, 10, end=999) sta, cast, samp, bot, pre, ctdtmp,
     1 ctdsal, ctdoxy, theta, sal, oxy, silca, nitrat, nitrit,
     2 phspht, talk, tcarb, ph, qualt

 
 10    format (5X, I3, 7X, I1, 6X, I2, 6X, I2, 1X, F7.1, 1X, F7.4,
     1 1X, F7.4, 1X, F8.3, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2,
     2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 1X, F7.1, 1X, F8.3, 
     3 1X, A12)

Stated in tabular form, the contents include the following:

_______________________________________________________________________________

Variable      Variable           Variable         Starting       Ending     
               type               width            column        column
_______________________________________________________________________________

sta           Numeric              3                 6              8
cast          Numeric              1                16             16
samp          Numeric              2                23             24
bot           Numeric              2                31             32
pre           Numeric              7                34             40
ctdtmp        Numeric              7                42             48
ctdsal        Numeric              7                50             56
ctdoxy        Numeric              8                58             65
theta         Numeric              7                67             73
sal           Numeric              9                75             83
oxy           Numeric              7                85             91
silca         Numeric              7                93             99
nitrat        Numeric              7               101            107
nitrit        Numeric              7               109            115
phspht        Numeric              7               117            123
talk          Numeric              7               125            131
tcarb         Numeric              7               133            139
ph            Numeric              8               141            148
qualt         Character           12               150            161
_________________________________________________________________________________

 
The variables are defined as follows:

sta              is the station number;

cast             is the cast number;

samp             is the sample number;

bot*             is the bottle number;

pre              is the CTD pressure (dbar);

ctdtmp           is the CTD temperature (C);

ctdsal*          is the CTD salinity [on the Practical Salinity Scale (PSS)];

ctdoxy*          is the CTD oxygen (mol/kg);

theta            is the potential temperature (C);

sal*             is the bottle salinity (on the PSS);

oxy*             is the oxygen concentration (mol/kg);

silca*           is the silicate concentration (mol/kg);

nitrat*          is the nitrate concentration (mol/kg);

nitrit*          is the nitrite concentration (mol/kg);

phspht*          is the phosphate concentration (mol/kg)

talk*            is the total alkalinity concentration (mol/kg);

tcarb*           is the total carbon dioxide concentration (mol/kg);

pH               is the pH at 25C;

qualt            is a 12-digit character variable that contains data-quality flag 
                 codes for parameters underlined with asterisks (*******) in the
                 file header.
_____________________________________________________________________

*Variables that are underlined with asterisks in the data file's header
indicate they have a
data-quality flag.  Data-quality flags are defined as follows:
    
    1 = sample for this measurement was drawn from water bottle but analysis was       
            not received;
    2 = acceptable measurement;
    3 = questionable measurement;
    4 = bad measurement;
    5 = not reported;
    6 = mean of replicate measurements;
    7 = manual chromatographic peak measurement;
    8 = irregular digital chromatographic peak integration;
    9 = sample not drawn for this measurement from this bottle.