     ORNL/CDIAC-84
     NDP-052
                                     
     
     
     TOTAL CARBON DIOXIDE, HYDROGRAPHIC, AND NITRATE
     MEASUREMENTS IN THE SOUTHWEST PACIFIC DURING AUSTRAL AUTUMN,
     1990: RESULTS FROM NOAA/PMEL CGC-90 CRUISE
     
     
     Contributed by
     Marilyn F. Lamb and Richard A. Feely
     Pacific Marine Environmental Laboratory
     Seattle, Washington

     and

     Lloyd Moore and Donald K. Atwood
     Atlantic Oceanographic and Meteorological Laboratory
     Miami, Florida
     
     Prepared by Alexander Kozyr
     Carbon Dioxide Information Analysis Center
     Oak Ridge National Laboratory
     Oak Ridge, Tennessee
     
     Environmental Sciences Division
     Publication No. 4420
     
     Date Published:  September 1995
     
     Prepared for the
     Global Change Research Program
     Environmental Sciences Division
     Office of Health and Environmental Research
     U.S. Department of Energy
     Budget Activity Number KP 05 02 00 0
     
     Prepared by the
     Carbon Dioxide Information Analysis Center
     OAK RIDGE NATIONAL LABORATORY
     Oak Ridge, Tennessee 37831-6335
     managed by
     LOCKHEED MARTIN ENERGY SYSTEMS, INC.
     for the
     U.S. DEPARTMENT OF ENERGY
          under contract DE-AC05-84OR21400




                                         ABSTRACT
     
     Lamb, M. F., R. A. Feely, L. Moore, and D. K. Atwood.  1995.  Total Carbon Dioxide,
       Hydrographic, and Nitrate Measurements in the Southwest Pacific during Austral Autumn,
       1990:  Results from NOAA/PMEL CGC-90 Cruise. ORNL/CDIAC-84, NDP-052.  Carbon
       Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee. doi: 10.3334/CDIAC/otg.ndp052 
         
         In support of the National Oceanic and Atmospheric Administration (NOAA) Climate and
     Global Change (C&GC) Program, Pacific Marine Environmental Laboratory (PMEL) scientists
     have been measuring the growing burden of greenhouse gases in the thermocline waters of the
     Pacific Ocean since 1980.  Collection of data at a series of hydrographic stations along longitude
     170  W during austral autumn of 1990 was designed to enhance understanding of the increase in
     the column burden of chlorofluorocarbons and carbon dioxide in the thermocline waters since the
     last expedition in 1984.
         This document presents the procedures and methods used to obtain total carbon dioxide
     (TCO2), hydrographic, and nitrate data during the NOAA/PMEL research vessel (R/V) Malcolm
     Baldrige CGC-90 Cruise.  Data were collected along two legs; sampling for Leg 1 began along
     170 W from 15 S to 60 S, then angled northwest toward New Zealand across the Western
     Boundary Current.  Leg 2 included a reoccupation of some stations between 30 S and 15 S on
     170 W and measurements from 15 S to 5 N along 170 W.  Along the cruise track 68 CTD
     stations were occupied for collection of chemical and hydrographic data.  The following data
     report summarizes the TCO2, salinity, temperature, and nitrate measurements from 63 stations. 
     In addition, potential density and potential temperature were calculated from the measured
     variables.
         The TCO2 concentration in seawater samples was measured using a coulometric/extraction
     system (Models 5011 and 5030, respectively) originated by Ken Johnson (Johnson et al. 1985,
     1987).  Throughout the cruise, the accuracy was determined to be within 0.15%, and the precision
     was within 0.12%.
         The NOAA/PMEL R/V Malcolm Baldrige CGC-90 Cruise data set is available without
     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 data retrieval routine files,
     a  documentation  file, and this printed documentation, which describes the contents and format of all
     files as well as the procedures and methods used to obtain the data.
     
          Keywords:   carbon dioxide; nitrate; hydrographic measurements; carbon cycle; Pacific Ocean     
     
     
     
     
     
                                          PART 1:
     
                                         OVERVIEW



     1. BACKGROUND INFORMATION
     
         Human activity is rapidly changing the composition of the earth's atmosphere, causing the
     greenhouse warming effect from excess carbon dioxide (CO2) and other trace gas species such as
     chlorofluorocarbons, methane, and nitrous oxide.  Combined, these gases play a critical role in
     controlling the earth's climate due to the increased trapping of outgoing infrared radiation.  This
     mechanism has a large potential for significantly altering the world's climate.
         Of all the anthropogenic CO2 that has been released into the atmosphere, only about half still
     remains there; it is the  missing  CO2 for which the global ocean is considered to be a dominant
     sink.  Understanding the assimilation process is critical in determining the moderating role the
     oceans will play in delaying and damping the greenhouse warming predicted in the coming
     decades.  Our goal is to help provide quantitative answers to the ways in which the oceans
     regulate and assimilate the excess CO2, so that we can better predict the ocean's role in the natural
     climate cycle.
         In response to these concerns, the Pacific Marine Environmental Laboratory (PMEL)
     conducted Cruise CGC-90 to the southwest Pacific onboard the research vessel (R/V) Malcolm
     Baldrige under the sponsorship of the Climate and Global Change Program(C&GC) of the
     National Oceanic and Atmospheric Administration (NOAA).  Chemical and hydrographic data
     from 68 CTD stations were collected along the cruise track.  Several tracers were
     measured during the cruise, including chlorofluorocarbons, helium, tritium, total carbon dioxide
     (TCO2), 13C, pH, nutrients, salinities and oxygens.  The following data report summarizes the
          TCO2, salinity, temperature, and nitrate data from 63 stations of this cruise.


      2. DESCRIPTION OF THE EXPEDITION.


      2.1 R/V Malcolm Baldrige Technical Details 
     
      The R/V Malcolm Baldrige (previously Researcher r103) is owned by the U.S. Department
     of Commerce and operated by NOAA.  The basic features of the vessel are described below.
     
      Port of registration:   Miami, Florida
      Call sign:              WTER
      Operator:               NOAA
      Launched:               October 1968
      Delivered:              June 1970
      Commissioned:           October 1970
      
      Basic Dimensions:
      length                  84.8 m 
      beam                    15.5 m 
      draft                   5.6 m  
      gross tons              2802        
      power                   3200 hp           
      maximum speed           15.0 knots     
      cruise speed            13.0 knots
      Personnel:              crew: 36; scientists: 14
      Navigation Equipment:   Radar Loran SatNav Gyro DopLog
      Hull:                   welded steel (ice-strengthened)
      Cranes:                 Stern, Midships
     
          
     2.2 NOAA/PMEL CGC-90 Cruise Information
     
      The following is the cruise information:
     
      Ship Name:   Malcolm Baldrige
      Cruise/Leg:  CGC-90/1,2
      Location:    Southwest Pacific Ocean
      Dates:       February 22 - April 16, 1990
     
      List of Participants:
     
      Chief Scientist:           David Wisegarver, NOAA/PMEL
      Project Manager:           Richard Feely
      Total CO2:                 Marilyn Lamb-Roberts
                                 Paulette Murphy
      CTD:                       Linda Mangum
                                 Kristy McTaggart
                                 Marguerite McCarty
                                 Dana Greeley
                                 Jeff Benson
      Salinity:                  Survey Department of NOAA R/V Malcolm Baldrige                     
      Nitrate:                   Lloyd Moore
                                 Don Atwood
      Computer Support:          Cathy Cosca
                                 Dan Lee
                                 Doug Wilson
      
      
     
     2.3 Brief Cruise Summary
     
         The cruise track for Leg 1 of CGC-90 started at 15 S/170 W and proceeded south along
     the meridional line; after reaching 60 S, it angled northwest, crossing the Western Boundary
     Current and ending in New Zealand.   The cruise track for Leg 2 crossed the Kermadec Trench,
     included a reoccupation of selected stations between 30 S and 15 S on 170 W, and additional
     stations along the meridional line crossing the equator, to 5 N (Table A-1 in Appendix A).  
         Stations 2 through 7 were sampled using a 24-position rosette package equipped with 10-L
     Niskin bottles, and a Neil Brown (Mark III) CTD sampling system.  While occupying Station
     8, the CTD cable parted, and the equipment package was lost.  Subsequently, the remaining
     stations (Stations 9 through 68) were sampled using a spare 12-position rosette with 10-L Niskin
     bottles and Neil Brown (Mark III) CTD sampling system.  Multiple casts were performed at these
     stations to ensure high density sample profiles.  Occasionally while at the most extreme latitudes,
     weather deteriorated and prevented the occupation of some stations.  Several stations sampled
     during Leg 1 were reoccupied on Leg 2 for data quality checks.  
           Two moorings were retrieved, and two deployed at the equator.


     3. DESCRIPTION OF VARIABLES AND METHODS
     
         Each station consisted of the lowering of a CTD/rosette package, upon which 10-L standard
     Niskin bottles were suspended.  Pressure, temperature, and CTD salinities for the tabulated data
     were taken from the calibrated CTD data.  The discrete water samples were drawn from the
     Niskin bottles upon retrieval of the rosette on deck.  Samples were collected for analyses of
     oxygen, chlorofluorocarbons (CFCs), helium, tritium (Leg 1 only), TCO2, 13C, pH (Leg 1 only),
     nutrients, and salinity.  In addition, underway partial pressure of CO2 (pCO2) was measured
     throughout the cruise.  This report addresses the temperature, salinity, TCO2, and nitrate data.
         CTD data were collected using a Neil Brown (Mark III) Instrument System.  Pressure,
     temperature, and conductivity were recorded on the downtrace, and the discrete water samples
     were collected on the upcast with an electronically fired rosette sampler.  The bottle salinity
     samples were analyzed with a Guideline Autosal, which was calibrated at the beginning of each
     day's run with a vial of Wormley standard seawater, and again after each case of samples was
     analyzed with another vial.  An accuracy of 0.002 Practical Salinity Scale (PSS) and a precision
     of 0.001 PSS were achieved.  A more detailed description of the CTD data processing has been
     published as a NOAA Data Report (McTaggart et al, 1993).
         Nutrient analyses included nitrate, silicate, and phosphate.  Due to accuracy and precision
     problems for silicate and phosphate, only nitrate data are included in this report.
         Nitrate samples were collected from each Niskin bottle in aged 60-mL linear polyethylene
     bottles and analyzed for dissolved inorganic nitrate (NO3--N).  Analyses were performed on
     samples from all CTD casts with a five-channel Technicon Auto-Analyzer (AA-II) aboard ship. 
     The analytical procedures and methodologies used in the analysis of nitrate are similar to those
     described by Armstrong et al. (1967), with modifications described in Atlas et al. (1971) and in
     a Technicon Corporation (1977) technical report.  The detection limit for nitrate was 0.39 umol/kg
     with a standard deviation of  0.1 umol/kg.  The precision of duplicate measurements was  0.25%,
     full scale.  The accuracy was assumed to be 1% because no absolute standards were available. 
     Nitrate measurements are reported in umol/kg at 1 atm and an assumed laboratory temperature of
     25 C.  Calibration standards ranged between 0 and 30 umol/kg; therefore, only samples within that
     concentration range are reported in Appendix B and data file.
         Upon retrieval of the CTD-rosette package on deck, samples for TCO2 were collected in 500-mL
     glass-stoppered bottles and poisoned with 0.5 mL of saturated HgCl2 solution to decrease
     bacterial oxidation of organic matter prior to analysis.  The samples were analyzed immediately
     when possible, but always within 24 h after collection.
         The coulometric technique for TCO2 analyses in seawater was originated by Ken Johnson
     (Johnson et al. 1985, 1987).  UIC, Inc. supplied the coulometic/extraction system (Models 5011
     and 5030, respectively).  The following changes were made to the standard extraction system: 
     1. Both the pipet and seawater sample bottle were jacketed (the sample bottle was placed in a
     jacketed beaker) and were connected to a circulating bath set at 25 C.  2. Ultra-pure N2 was used
     for both carrier gas and sample delivery; prior to hook-up to glassware, the N2 was sent through
     an in-line NaOH (Malcosorb) scrubber to remove any CO2.  3. The condensing column was
     connected to a circulating bath filled with antifreeze and run at 1 C.  4. An ORBO (activated Si
     gel from Supelco) tube was placed in-line between the glassware and titration cell to eliminate any
     excess moisture.  5. Standardization of instrumentation was modified (as described later in this
     section).  The computer interfaced to the system was a Zenith ZBF-2339-BK.  The program
     supplied by UIC was modified significantly, to accommodate our particular needs.  In coulometric
     analysis of TCO2, all carbonate species in seawater (CO2(aq), H2CO3, HCO3- and CO32-) are
     converted to CO2 by addition of excess acid.  The evolved CO2 is then moved into the titration
     cell by N2 carrier gas where it is titrated potentiometrically by reacting quantitatively with
     ethanolamine to form hydroxyethyl carbamic acid; this is titrated with OH- ions electrogenerated
     by the reduction of H2O at a platinum cathode:
     
                                CO2 + HO(CH2)2NH2 -- HO(CH2)2NHCOO- + H+
                                            Ag(s) -- Ag+ + e-
                                         H2O + e- -- 0.5H2(g) + OH-
                                         H+ + OH- -- H20
     
         The equivalence point is detected photometrically with thymolphthalein as an indicator.  The
     cell solution is blue at the equivalence point of 10.5 pH and colorless at pH 9.3 after the addition
     of CO2 in aqueous solutions.  CO2 drives down the pH and raises percent transmittance.  As the
     acid is titrated, pH increases (hence, the blue color returns) and percent transmittance decreases,
     thus causing the titration current to pass from high to low to zero as the equivalence point is
     approached and sensed by the optical detector.  The CO2 level is calculated based on the quantity
     of electricity required to reach the equivalence point and the time of passage.  The entire sequence
     takes from 8 to 11 min.
         The volume of the pipet was ~ 50 mL, and was calibrated in the laboratory before and after
     the cruise.  The pipet was cleaned by drawing a 25% solution of NaOH into the cell and allowing
     it to soak overnight.  This eliminated any organic film inside the pipet and ensured a clean
     delivery.  Pipet calibrations were conducted to be within the measured pipet temperature range
     during the cruise (24.5 C 25.5 C) utilizing a circulating bath.  Milli-Q water was drawn into the
     pipet in the exact manner that a liquid standard or seawater sample was handled.  The water was
     delivered by N2 (flow rate is 200 mL/min) into a tared, ground-glass stoppered mixing flask, and
     drained for an additional 5 s (monitored by a stop-watch) to allow the droplets of water to be
     delivered; the flask was then immediately stoppered and weighed on a Mettler AE240 balance. 
     Approximately 15-20 samples were collected per experiment.  The following references were used
     to correct the weighings:  1. Volume Properties of Ordinary Water.  2. Reductions of Weighings
     in Air to Vacuo for Brass Weights and a Water Density of 1.00.  Density of air used was 0.0012. 
     3.  Temperature Correction for Glass Volumetric Apparatus.
         The corrected volumes were then linearly regressed with temperature, and a calibration curve
     was established (typical r2 = 0.80).
         Schott-Duran glass 500-mL bottles were annealed at 450 C for 1 h, then cleaned in a
     dishwasher with commercial grade dishwashing detergent.  Prior to collection of samples, the solid
     ground-glass stoppers were coated with Type M Apiezon grease.
         Acid used to convert carbonate species to CO2 was a 1:10 solution of Baker reagent grade
     H3PO4.  All coulometric chemicals (cathode solution, anode solution, and KI) were purchased from
     UIC, Inc.
         Liquid standards were made up in a 0.7 M solution of KCl.  The standards were treated just
     as a seawater sample and were delivered through the pipet under the same conditions.  The
     standard used was Na2CO3 (Ultrex, Lot 935113); the KCl was reagent grade from Mallinkrodt.
         The Na2CO3 was prepared in the laboratory by baking at 260 270 C for 0.5 h, and desiccated
     overnight.  The standards were weighed into pre cleaned ground-glass stoppered vials with weights
     ranging from 0.20 to 0.25 g.  They were immediately stored in an evacuated desiccator with fresh
     Si gel until prepared.  The KCl was baked in a muffle furnace for 0.5 h at 260-270 C, and cooled
     in a desiccator overnight.
         The KCl solution and liquid standards were prepared in the following manner:  Milli-Q water
     was boiled in a 3-L boiling flask for 20 min to drive off CO2, then cooled overnight with a NaOH
     column attached to the neck of the flask.  A glove-box was purged with ultra-pure N2 for about
     20 min; in the glove box, the KCl was mixed with the CO2-free water in a clean 2-L volumetric. 
     Half of this solution was stored in a 1-L sample bottle with siphon tube and clamp and was used
     to determine blank values for the KCl (see following discussion).  The other half was used to
     make the Na2CO3 in a 1-L volumetric.  After the standard equilibrated, it was poured into a 1-L
     bottle with siphon tube and clamp.  This work was performed in an N2 environment in the glove
     box.
         The KCl solution was analyzed to determine a mean blank for the standard.  Being careful
     not to expose the KCl solution to the atmosphere, it was drawn into the pipet in the same way as
     a sample.  When handled in this way, the KCl blank was very constant, usually with a mean of
     around 6.0 +/- 0.3 ug C for an individual batch and an  over the cruise  mean of 6 +/- 1 ug C.
         The standards yielded a mean calibration factor of 99.6588% +/- 0.0600 (n = 25).
         A Certified Reference Material (CRM) was prepared and bottled by Dr. Andrew Dickson of
     the Scripps Institution of Oceanography (SIO).  The TCO2 concentration of the CRM was
     determined to be 2020 +/- 0.009 umol/kg by manometric technique in the laboratory of Dr. Charles
     Keeling of the SIO.  Bottles of the CRM were taken on the cruise and analyzed frequently to
     determine the accuracy and precision of the coulometric method; the results are reported in
     Table 1.  Throughout the cruise, the accuracy was determined to be within 0.15% and the
     precision was within 0.12%.  Replicates analyzed at three different stations throughout the cruise
     yielded a precision of +/- 0.05%.  The reported TCO2 data have been corrected to reflect the
     difference in accuracy to the CRM; the correction applied is +3 umol/kg TCO2.
         Samples were analyzed with the same method as standards, that is, 4.5 mLs of acid were
     dispensed into the reaction vessel, and 2-3 minutes were allowed to pass to purge CO2 from the
     acid.  Following that, the pipet was rinsed twice with the sample, and the third fill was isolated
     and used for analysis.  The sample was emptied into the reaction vessel, and allowed to drain for
     an additional 5 seconds (monitored via stopwatch) to allow droplets of water to be delivered.
     
     
     Table 1.  Certified Reference Material (batch 1) analyzed for total CO2 during 
               R/V Malcolm Baldrige CGC-90 Cruise
     
     

                               ----------------------
                                 Date          TCO2 
                                            (umol/kg)
                               ----------------------
                               24 Feb. 1990    2012
                               25 Feb. 1990    2024
                               27 Feb. 1990    2014
                                2 Mar. 1990    2015
                                5 Mar. 1990    2012
                                5 Mar. 1990    2016
                                6 Mar. 1990    2019
                                7 Mar. 1990    2019
                                8 Mar. 1990    2019
                               10 Mar. 1990    2015
                               11 Mar. 1990    2016
                               12 Mar. 1990    2016
                               13 Mar. 1990    2017
                               15 Mar. 1990    2017
                               16 Mar. 1990    2017
                               20 Mar. 1990    2017
                               29 Mar. 1990    2017
                               30 Mar. 1990    2014
                                2 Apr. 1990    2018
                                3 Apr. 1990    2014
                                5 Apr. 1990    2016
                                6 Apr. 1990    2017
                                7 Apr. 1990    2018
                                7 Apr. 1990    2018
                               11 Apr. 1990    2020
                               12 Apr. 1990    2017
                               --------------------
                                       Mean    2017
                                   Sta. Dev     2.5
                               --------------------

     
     
         Sigma-t and sigma-theta were calculated using standard UNESCO algorithms (Fofonoff and
     Millard 1983), and the CTD measured in situ temperature and bottle salinities.  When no bottle
     salinities were available or when they were defined as a questionable or unacceptable
     measurements, CTD salinities were used in the calculation.
           


     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. 
     Reviews involve examining the data for completeness, reasonableness, and accuracy.  Although
     they have common objectives, these reviews are tailored to each data set, often requiring extensive
     programming efforts.  In short, the QA process is a critical component in the value-added concept
     of supplying accurate, usable data for researchers. 
         The following summarizes the data QA checks and processing performed by CDIAC on the
     data obtained during the NOAA/PMEL R/V Malcolm Baldrige CGC-90 Cruise in the Southwest
     Pacific.
     
     1. These data were provided to CDIAC as two ASCII-formatted files and accompanying printed
        documentation (NOAA Data Report ERL PMEL-42) (Lamb et al. 1993).  A FORTRAN 77
        retrieval code was written and used to reformat the original files.
     
     2. To check for obvious outliers all data were plotted by use of a PLOTNEST.C program
        written by Stewart C. Sutherland, of the 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. 
        Several outliers were identified and flagged after consultation with the principal investigators.
     
     3. To generate a section profile plot of TCO2 concentrations along the 170 W, the
        PLOTSECT.C program written by Stewart C. Sutherland, LDEO was used.
     
     4. To identify  noisy  data and possible systematic methodological errors, property-property
        plots for all parameters were generated, carefully examined, and compared with
        plots from previous expeditions in the Southwest Pacific.
     
     5. To identify possible instrumentation drifts and methodological errors, the data
        intercomparison for reoccupied stations was provided.
     
     6. All variables were checked for values exceeding physical limits, such as sampling depth
        values that are greater than the given bottom depths.
     
     7. Station locations (latitudes and longitudes) and sampling dates were examined for consistency
        with maps and with cruise information supplied by Lamb et al. (1993).  
     
     8. The designation for missing values, given as "-99.00"  in the original files, was changed to
        "-999.90".
        
  
     
     
     5. HOW TO OBTAIN THE DATA AND DOCUMENTATION
     
      This data base is available upon request in machine-readable form, free-of-charge from
     CDIAC.  CDIAC will also distribute subsets of the data base as needed.  It can be acquired on
     9-track magnetic tape; 8-mm tape; 150-mB, quarter-inch tape cartridge; IBM-formatted floppy
     diskettes; or from CDIAC's anonymous File Transfer Protocol (FTP) area via Internet (see FTP
     address below).  Requests should include any specific media instructions (i.e., 1600 or 6250 BPI,
     labeled or nonlabeled, ASCII or EBCDIC characters, and variable- or fixed-length records; 3.5-
     or 5.25-inch floppy diskettes, high or low density; and 8200 or 8500 format 8-mm tape) required
     by the user to access the data.  Magnetic tape requests not accompanied by specific instructions
     will be filled on 9-track, 6250 BPI, standard-labeled tapes with EBCDIC characters.  Requests
     should be addressed to:
     
      Carbon Dioxide Information Analysis Center
      Oak Ridge National Laboratory
      Post Office Box 2008
      Oak Ridge, Tennessee 37831-6335
      U.S.A.
     
      Telephone:             (615) 574-0390 or (615) 574-3645
      Fax:                   (615) 574-2232
     
      Electronic Mail:       INTERNET: CDIAC@ORNL.GOV
      
     The data files can be also acquired from CDIAC's anonymous FTP account via Internet:
     
                 FTP to cdiac.esd.ornl.gov (128.219.24.36)
                 Enter "ftp" or "anonymous" as the userid
                 Enter your electronic mail address as the password (e.g., alex@alex.esd.ornl.gov )
                 Change to the directory  "/pub/ndp052" 
                 Acquire the files using the FTP "get" or "mget" command
     
     or World Wide Web URL:
     
                 http://cdiac.esd.ornl.gov/cdiac/
     
     
     6. REFERENCES
     
     Armstrong, F. A. J., C. R. Stearns, and J. D. H. Strickland.  1967.  The measurement of upwelling
       and subsequent biological processes by means of the Technicon Auto-Analyzer and associated
       equipment.  Deep-Sea Res. 14:381-89.
     
     Atlas, E. L., J. C. Callaway, R. D. Tomlinson, L. I. Gordon, L. Barstow, and P. K. Park.  1971. 
       A Practical Manual for Use of the Technicon Autoanalyzer Nutrient Analysis, revised. 
       Oregon State University Technical Report 215, Reference No. 71-22.
     
     Fofonoff, N. P., and R. C. Millard, Jr.  1983.  Algorithms for computation of fundamental
       properties of seawater.  UNESCO Technical Paper.
     
     Johnson, K. M., A. E. King, and J. McN. Sieburth.  1985.  Coulometric TCO2 analyses for marine
       studies; an introduction.  Mar. Chem. 16:61-82.
     
     Johnson, K. M., P. J. Williams, L. Brandstrom, and J. McN. Sieburth.  1987.  Coulometric total
       carbon analysis for marine studies:  automation and calibration.  Mar. Chem. 21:117-33.
     
     McTaggart K. E., D. Wilson, and L. J. Mangum.  1993.  CTD Measurements Collected on a
       Climate and Global Change Cruise along 170 N during February April 1990.  NOAA Data
       Report.  URL-PMEL-44.  Pacific Marine Environmental Laboratory, Seattle, Wash.
     
     Lamb M. F., R. A. Feely, L. Moore, and D. K. Atwood.  1993.  Total CO2 and Nitrate
       Measurements In the Southwest Pacific During Austral Autumn, 1990.  NOAA Data Report
       ERL PMEL-42.  Pacific Marine Environmental Laboratory, Seattle, Wash.
     
     Technicon Industrial Systems.  1977.  Nitrate and nitrite in water and seawater.  Technicon Auto-
       Analyzer II, Industrial Method No. 158 71W/A. Technicon Instrument Corporation,
       Tarrytown, N.Y.
     
     UNESCO Technical Papers in Marine Science.  1991.  Reference Materials for Oceanic Carbon
       Dioxide Measurements 60.
     
     
   

                                         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
     (Table 2).  Because CDIAC distributes the data set in several ways (e.g., via anonymous FTP,
     floppy diskette,  and on 9-track magnetic tape), each of the five files is referenced by both an
     ASCII file name, which is given in lower-case, bold-faced type (e.g., ndp052.txt), and a file number. 
     The remainder of this section describes (or lists, where appropriate) the contents of each file.  The
     files are discussed in the order in which they appear on the magnetic tapes.
     
     
               Table 2.  Content, size, and format of data files
     
                                        
       ------------------------------------------------------------------------------------ 
           File number, name,                Logical     File size    Block     Record
           and description                   records     in bytes     size      length
       ------------------------------------------------------------------------------------                                        
        1. ndp052.txt:                             954        50,859      8,000       80
           a detailed description
           of the cruise network, the
           two FORTRAN 77 data
           retrieval routines, and the
           two oceanographic data
           files
     
        2. stainv.for:                          30         1,062      8,000       80
           a FORTRAN 77 data retrieval
           routine to read and print
           cgc90sta.inv (File 4)
     
        3. cgc90dat.for:                        36         1,368      8,000       80
           a FORTRAN 77 data retrieval
           routine to read and print
           cgc90.dat (File 5)
     
        4. cgc90sta.inv:                        63         3,906      4,100       41
           a listing of the station locations,
           sampling dates, and sounding 
           bottom depths for each station
     
        5. cgc90.dat:                         1,224       134,640    16,000      160
           hydrographic, carbon dioxide,
           and nitrate data from 63 stations.
               
                                              _____        ______                             
           Total                              2,307       191,835
       -----------------------------------------------------------------------------------          
                                       
     



     7.1 ndp052.txt (File 1)
     
          This file contains a detailed description of the data set,  the two FORTRAN 77 data retrieval
     routines, and the two oceanographic data files.  It 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 data retrieval routine to read and print cgc90sta.inv (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 the 
     cgc90sta.inv file.
     
     c****************************************************************
     c* This is a FORTRAN 77 retrieval code to read and print the    *        
     c* file named "cgc90sta.inv" (File 4)                           *
     c**************************************************************** 
            INTEGER  sta, cast, dep 
            REAL lat, lon
            CHARACTER date*8, time*4
            OPEN (unit=1, file='cgc90sta.inv')
            OPEN (unit=2, file='pmel90sta.inv')
            write (2, 5)
     
      5     format (2X,'STANBR',1X,'CASTNBR',1X,'LATITUDE',1X,
          1 'LONGITUDE',6X,'DATE',4X,'TIME',3X,'DEPTH',/,18X,
          2 'DEC.DEG',3X,'DEC.DEG',5X,'D/M/Y',5X,'GMT',7X,'M',/)
     
      7     CONTINUE    
            read (1, 10, end=999) sta, cast, lat, lon, date, time,
          1 dep
      10    format (6X, I2, 5X, I3, 2X, F7.3, 2X, F8.3, 2X, A8, 4X,
          1 A4, 4X, I4)
       
            write (2, 20) sta, cast, lat, lon, date, time,
          1 dep
      20    format (6X, I2, 5X, I3, 2X, F7.3, 2X, F8.3, 2X, A8, 4X,
          1 A4, 4X, I4)
            GOTO 7
     
      999   close(unit=1)    
            close(unit=2)
            stop
            end
     
     
     
    
     
     
     7.3 cgc90dat.for (File 3)
     
          This file contains a FORTRAN 77 data retrieval routine to read and print cgc90.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 the
     cgc90.dat file.
     
     c****************************************************************
     c*  This is a FORTRAN 77 data retrieval code to read and format *
     c*  the file named "cgc90.dat" (File 5)                         *        
     c****************************************************************
       
            INTEGER  sta, samp, qcfl
            REAL pres, temp, theta, ctdsal, botsal, sigma, sigmat
            REAL no3, tco2
            OPEN (unit=1, file='cgc90.dat')
            OPEN (unit=2, file='pmel90.dat')
            write (2, 5)
     
      5     format (3X,'STANBR',3X,'SAMPID',3X,'CTDPRS',2X,'CTDTEMP',4X,
          1 'THETA',3X,'CTDSAL',3X,'BOTSAL',4X,'SIGMA',2X,'SIGMA-T',2X,
          2 'NITRATE',4X,'TCARB',3X'QC_FLAG',/,23X'DBAR',3X,'DEG(C)',
          3 3X,'DEG(C)',6X,'PSS',6X,'PSS',4X,'THETA',11X,'UMOL/KG',2X,
          4 'UMOL/KG',/,56X,'*******',20X,'*******',2X,'*******')
     
      7     CONTINUE
            read (1, 10,end=999) sta, samp, pres, temp, theta, ctdsal,
          1 botsal, sigma, sigmat, no3, tco2, qcfl
     
      10    format (7X,I2,4X,I5,3X,F6.1,3X,F6.3,3X,F6.3,3X,F6.3,1X,F8.3,
          1 3X,F6.3,3X,F6.3,1X,F8.3,2X,F7.1,7X,I3)
      
            write (2, 20) sta, samp, pres, temp, theta, ctdsal,
          1 botsal, sigma, sigmat, no3, tco2, qcfl
     
      20    format (7X,I2,4X,I5,3X,F6.1,3X,F6.3,3X,F6.3,3X,F6.3,1X,F8.3,
          1 3X,F6.3,3X,F6.3,1X,F8.3,2X,F7.1,7X,I3)
            GOTO 7
     
     999    close(unit=1)
            close(unit=2)
            stop
            end
     
     
     
      
     
     7.4 cgc90sta.inv (File 4)
     
          This file provides station inventory information for each of 63 stations occupied during the
     R/V Malcolm Baldrige CGC-90 Cruise.  There is one entry for each station. Each line contains
     a section number, cast number, latitude, longitude, sampling date (day/month/year), sampling time,
     and sounding depth of the station.  The file is sorted by station number and can be read using the
     following FORTRAN 77 code (contained in stainv.for, which is File 2):
     
            INTEGER  sta, cast, dep 
            REAL lat, lon
            CHARACTER date*8, time*4
            read (1, 10, end=999) sta, cast, lat, lon, date, time,
          1 dep
      10    format (6X, I2, 5X, I3, 2X, F7.3, 2X, F8.3, 2X, A8, 4X,
          1 A4, 4X, I4)
            
     Stated in tabular form, the contents include the following:
                                        
                                        
     -------------------------------------------------------------------------------
                             Variable        Variable         Starting       Ending
     Variable                  type            width           column        column
     -------------------------------------------------------------------------------                                    
     
     sta                      Numeric            2                7             8
     cast                     Numeric            3               14            16
     lat                      Numeric            7               19            25
     lon                      Numeric            8               28            35
     date                    Character           8               38            45
     time                    Character           4               50            53
     dep                      Numeric            4               58            61
     ------------------------------------------------------------------------------                                   
     
     where
     
     sta    is the station number;
     
     cast   is the cast number;
     
     lat    is the latitude of the station (in decimal degrees). 
            Stations in the Southern Hemisphere have negative latitudes;
     
     lon    is the longitude of the station (in decimal degrees). 
            Stations in the Western Hemisphere have negative longitudes
     
     date   is the date the station was sampled (day/month/year);
     
     time   is the time the station was sampled (Greenwich Mean Time);
     
     dep    is the sounding depth of the station (in m).
     


     7.5 cgc90.dat (File 5) 
     
            This file provides hydrographic, carbon dioxide, and nitrate data for the 63 stations occupied
     during R/V Malcolm Baldrige CGC-90 Cruise in the Southwest Pacific.  Each line of the file
     consists of a station number, sample ID, CTD pressure, CTD temperature, potential temperature,
     CTD salinity, bottle salinity, sigma-t, sigma-theta, nitrate, total CO2, and data quality flags.  The
     file is sorted by station number and pressure and can be read using the following FORTRAN 77
     code (contained in cgc90dat.for, which is File 3):
     
            INTEGER  sta, samp, qcfl
            REAL pres, temp, theta, ctdsal, botsal, sigma, sigmat
            REAL no3, tco2
            read (1, 10,end=999) sta, samp, pres, temp, theta, ctdsal,
          1 botsal, sigma, sigmat, no3, tco2, qcfl
      10    format (7X,I2,4X,I5,3X,F6.1,3X,F6.3,3X,F6.3,3X,F6.3,1X,F8.3,
          1 3X,F6.3,3X,F6.3,1X,F8.3,2X,F7.1,7X,I3)
       
     
     Stated in tabular form, the contents include the following:
     
                                        
     
                             Variable        Variable         Starting       Ending
     Variable                  type            width           column        column
                                        
     
     sta                      Numeric            2                8             9
     samp                     Numeric            5               14            18
     pres                     Numeric            6               22            27
     temp                     Numeric            6               31            36
     theta                    Numeric            6               40            45
     ctdsal                   Numeric            6               49            54
     botsal                   Numeric            8               56            63
     sigma                    Numeric            6               67            72
     sigmat                   Numeric            6               76            81
     no3                      Numeric            8               83            90
     tco2                     Numeric            7               93            99
     qcfl                     Numeric            3              107           109
                                        
     
     where
     
     sta     is the station number;
     
     samp    is the sample number;
     
     pres    is the CTD pressure (in dbar);
     
     temp    is the CTD temperature (in deg. C);
     
     theta   is the potential temperature (in deg. C);
     
     ctdsal  is the CTD salinity (in PSS);
     
     botsal* is the bottle salinity (in PSS);
     
     sigma   is sigma-theta (in sigma units);
     
     sigmat  is sigma-t (in sigma units);
     
     no3*    is the nitrate concentration (in umol/kg);
     
     tco2*   is the total carbon dioxide concentration (in umol/kg);
     
     qcfl    is an 3-digit variable that contains data quality flag codes for parameters flagged
             by an asterisk in the output file.
     
             Quality flags definitions:

             2            =  Acceptable measurement;
             3            =  Questionable measurement;
             5            =  Not reported;
             9            =  Sample not drown for this measurement from this bottle.
     
     
     
     
     
     8. VERIFICATION OF DATA TRANSPORT

     
            The data files contained in this numeric data package can be read by using the FORTRAN
     77 data retrieval programs provided.  Users should visually examine each data file to verify that
     the data were correctly transported to their systems.  To facilitate the visual inspection process,
     partial listings of each data file are provided in Tables 3 and 4.  Each of these tables contains the
     first and last five lines of a data file.
     
     
     
     
     Table 3.  Partial listing of  cgc90sta.inv  (File 4)
     
                                        
     
     First five lines of the file:
     
            2       2  -15.001  -170.005  24/02/90    0151    4817
            3       3  -16.472  -169.993  24/02/90    1238    5073
            4       4  -18.003  -170.007  24/02/90    2149    4929
            5       7  -20.012  -169.993  25/02/90    2049    5320
            7      10  -21.992  -169.997  26/02/90    1300    4839
     
     
     
     
     Last five lines of the file:
     
           64     105    0.000  -170.001  11/04/90    1400    5612
           65     106    0.500  -170.005  11/04/90    1837    5285
           66     107    1.001  -170.005  11/04/90    2145    5316
           67     108    2.005  -170.015  12/04/90    0308    5357
           68     109    5.001  -170.010  12/04/90    1655    7161
     
     
     
                                        
     Table 4.  Partial listing of  cgc90.dat  (File 5)
     
                                        
     
     First five lines of the file:
     
             2      222      3.0   28.197   28.196   35.525   35.527   22.729  
     22.729 -999.900   -999.9       259
             2      110      3.6   28.214   28.213   35.531 -999.900   22.727  
     22.726    0.391   1954.7       522
             2      109     18.2   28.152   28.147   35.531 -999.900   22.748  
     22.746 -999.900   2047.9       553
             2      108     39.0   28.043   28.034   35.522   35.527   22.782  
     22.779    0.391   1966.5       223
             2      219     47.7   27.715   27.704   35.521   35.513   22.879  
     22.876    0.391   -999.9       229
     
      
      
     
     
     
     Last five lines of the file:
     
            68    10945    196.6   14.442   14.413   34.595   34.613   25.801  
     25.795   18.641   2124.9       222
            68    10953    295.9    9.985    9.951   34.668   34.661   26.696  
     26.690 -999.900   2222.9       252
            68    10943    496.6    7.978    7.927   34.611 -999.900   26.979  
     26.972 -999.900   2263.0       552
            68    10942    695.1    6.208    6.145   34.558   34.553   27.181  
     27.173 -999.900   2292.0       253
            68    10941    996.9    4.493    4.413   34.568   34.564   27.396  
     27.387 -999.900   2310.1       252
       
     
     
     

                                        
                                       APPENDIX A


                               STATION INVENTORY
     
            This appendix lists station inventory information for the 63 sites occupied during R/V
     Malcolm Baldrige CGC-90 Cruise in the Southwest Pacific.  The meanings of the column
     headings in Table A-1 are as follows.
     
     STANBR       is the station number;
     
     CASTNBR      is the cast number;
     
     LATITUDE     is the latitude of the station (in decimal degrees). Stations in the Southern
                  Hemisphere have negative latitudes;
     
     LONGITUDE    is the longitude of the station (in decimal degrees). Stations in the Western
                  Hemisphere have negative longitudes;
     
     DATE         is the sampling date (day/month/year);
     
     TIME         is the sampling time [Greenwich Mean Time (GMT)];
     
     DEPTH        is the sounding bottom depth of each station (in m).
     
     
     
   
     
     
     Table A.1.  Station  inventory information for the 63 sites occupied during 
                 R/V Malcolm Baldrige CGC-90 Cruise
     
     
       STANBR CASTNBR LATITUDE LONGITUDE      DATE    TIME   DEPTH
                       DEC.DEG   DEC.DEG     D/M/Y     GMT       M
     
            2     1-2  -15.001  -170.005  24/02/90    0151    4817
            3       3  -16.472  -169.993  24/02/90    1238    5073
            4       4  -18.003  -170.007  24/02/90    2149    4929
            5     5-7  -20.012  -169.993  25/02/90    2049    5320
            7    9-10  -21.992  -169.997  26/02/90    1300    4839
            9   11-13  -25.022  -170.015  27/02/90    1837    5712
           10   14-15  -27.053  -170.015  28/02/90    0952    5316
           11   16-18  -30.005  -170.043  01/03/90    0441    5429
           12   19-21  -32.553  -170.052  02/03/90    0030    5568
           13   22-24  -35.023  -170.010  02/03/90    2115    5225
           14   25-26  -37.543  -170.037  03/03/90    1252    5170
           15   27-29  -40.028  -170.028  04/03/90    0706    4626
           16   30-31  -40.968  -170.483  04/03/90    1908    4323
           17      32  -41.490  -170.723  05/03/90    0041    3984
           18      33  -41.982  -170.983  05/03/90    0554    2974
           19   34-35  -42.478  -171.208  05/03/90    1225    1857
           20      36  -43.502  -170.853  05/03/90    1902    2904
           21      37  -43.985  -170.693  06/03/90    0054    4473
           22      38  -44.370  -170.328  06/03/90    0641    5108
           23   39-41  -46.045  -170.001  06/03/90    2207    5190
           24      42  -47.007  -170.013  07/03/90    0538    5252
           25   43-44  -48.022  -169.915  07/03/90    1509    5294
           26   45-47  -50.067  -170.070  08/03/90    0844    5279
           27   48-49  -51.967  -169.985  09/03/90    0027    5054
           28   50-51  -56.768  -170.068  10/03/90    0612    4822
           29   52-53  -60.010  -169.883  11/03/90    0502    4139
           30   54-55  -55.997  -174.168  12/03/90    2212    4970
           31   56-57  -53.948  -176.158  13/03/90    1304    5289
           32      58  -50.505  -179.395  15/03/90    0620    4448
           33      59  -49.492  -179.745  15/03/90    1420    2012
           34      60  -49.725  -179.998  16/03/90    0724    3111
           35      61  -49.848  -179.878  16/03/90    1146    4030
           36      62  -50.483  -179.357  18/03/90    0704    4458
           38      65  -34.648  -178.637  28/03/90    0948    6556
           39      66  -32.497  -178.313  28/03/90    2141    5091
           40      67  -32.510  -178.523  29/03/90    0237    4249
           41   68-69  -32.488  -178.767  29/03/90    1000    3003
           42      70  -32.483  -178.502  29/03/90    1257    4211
           43      71  -32.493  -178.297  29/03/90    1554    5004
           44   72-73  -32.510  -177.998  30/03/90    0029    6005
           45   74-75  -32.490  -175.502  30/03/90    1642    5556
           46      76  -32.480  -171.478  31/03/90    1104    5259
           47      77  -30.000  -170.007  01/04/90    0233    5532
           48   78-80  -25.020  -170.030  02/04/90    0857    5834
           49   81-82  -22.507  -170.008  03/04/90    0042    5645
           50   83-85  -20.025  -170.013  03/04/90    1926    5502
           51      86  -17.492  -170.005  04/04/90    0841    4848
           52   87-89  -15.005  -170.007  05/04/90    0438    4903
           53      90  -11.440  -169.608  05/04/90    2237    5216
           54      91  -10.102  -169.503  06/04/90    0700    5332
           55   92-93  -10.092  -170.000  06/04/90    1546    5260
           56      94  -10.088  -170.248  06/04/90    2053    5141
           57      95   -9.492  -170.213  07/04/90    0238    4515
           58   96-98   -5.013  -170.020  08/04/90    0526    5511   
           59      99   -2.005  -170.007  08/04/90    2116    5214
           60     100   -0.995  -170.020  09/04/90    0244    5435
           61     101   -0.498  -170.007  09/04/90    0605    5698
           62 102-104    0.000  -170.020  09/04/90    0931    5342
           64     105    0.000  -170.001  11/04/90    1400    5612
           65     106    0.500  -170.005  11/04/90    1837    5285
           66     107    1.001  -170.005  11/04/90    2145    5316
           67     108    2.005  -170.015  12/04/90    0308    5357
           68     109    5.001  -170.010  12/04/90    1655    7161
