ORNL/CDIAC-132
                                                                        NDP-077
     CARBON DIOXIDE, HYDROGRAPHIC, AND CHEMICAL DATA OBTAINED
     DURING THE R/V KNORR CRUISES 138-3, -4, AND -5 IN THE SOUTH PACIFIC
     OCEAN  (WOCE SECTIONS P6E, P6C, AND P6W, MAY 2 - JULY 30, 1992)
                         Contributed by
     Kenneth M. Johnson*, Meredith Haines**, Robert M. Key***, Craig Neill*,
     Bronte Tilbrook****, Rick Wilke*, and Douglas W. R. Wallace*****
     *Department of Applied Science, Brookhaven National Laboratory, New York, U.S.A.
     **Department of Marine Science, University of South Florida, Florida, U.S.A.
     ***Department of Geosciences, Princeton University, Princeton, New Jersey, U.S.A.
     ****Division of Oceanography, Commonwealth Scientific and Industrial Research
         Organisation,  Hobart, Tasmania, Australia
     *****Forschungsbereich Marine Biogeochemie, Institut fuer Meereskunde
          Universitaet Kiel, Kiel, Germany
                  Prepared by Alexander Kozyr
           Carbon Dioxide Information Analysis Center
                  Oak Ridge National Laboratory
                  Oak Ridge, Tennessee, U.S.A.
                    Date Published: August 2001
                        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
     ACRONYMS
     ADCP     acoustic Doppler current profiler
     BOD      biological oxygen demand
     BNL      Brookhaven National Laboratory
     14C      radiocarbon
     CALFAC   calibration factor
     CDIAC    Carbon Dioxide Information Analysis Center
     CFC      chlorofluorocarbon
     CO2      carbon dioxide
     CTD      conductivity, temperature, and depth sensor
     CSIRO    Commonwealth Scientific and Industrial Research Organisation
     CRM      certified reference material
     CUV      Catholic University Valparaiso
     DOE      U.S. Department of Energy
     FTP      file transfer protocol
     GC       gas chromatograph
     GLODAP   Global Ocean Data Analysis Project
     GMT      Greenwich mean time
     GSV      gas sampling valve
     IAPSO    International Association for the Physical Sciences of the Ocean
     JGOFS    Joint Global Ocean Flux Study
     LDEO     Lamont-Doherty Earth Observatory
     nm       nautical mile
     NDP      numeric data package
     NOAA     National Oceanic and Atmospheric Administration
     ODF      Ocean Data Facility
     ONR      Office of Naval Research
     OSU      Oregon State University
     pCO2     partial pressure of CO2
     PMEL     Pacific Marine Environmental Laboratory
     PSS      Practical Salinity Scale
     PU       Princeton University
     QA       quality assurance
     QC       quality control
     R/V      research vessel
     RSMAS    Rosenstiel School of Marine and Atmospheric Sciences
     SIO      Scripps Institution of Oceanography
     SOMMA    Single-Operator Multiparameter Metabolic Analyzer
     TALK     total alkalinity
     TCO2     total carbon dioxide
     UW       University of Washington
     VFC      voltage to frequency converter
     WHOI     Woods Hole Oceanographic Institution
     WHPO     WOCE Hydrographic Program Office
     WOCE     World Ocean Circulation Experiment
     WHP      WOCE Hydrographic Program
               
                            ABSTRACT
 Johnson, K. M., M. Haines, R. M. Key, C. Neill, B. Tilbrook, R. Wilke, D. W. R. Wallace.
     2001.  Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V
     Knorr Cruises 138-3, -4, and -5 in the South Pacific Ocean (WOCE Sections P6E, P6C,
     and P6W, May 2 - July 30, 1992), A. Kozyr (ed.).  ORNL/CDIAC-132, NDP-077.  Carbon
     Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department
     of Energy, Oak Ridge, Tennessee.
     This data documentation discusses the procedures and methods used to measure total
     carbon dioxide (TCO2) and partial pressure of carbon dioxide (pCO2) at hydrographic stations
     during the research vessel (R/V) Knorr oceanographic cruises 138-3, -4, and -5 in the South
     Pacific Ocean (Section P6).  The work was divided into three legs designated as P6E, P6C,
     and P6W which correspond to cruises 138-3, -4, and -5, respectively.  Conducted as part of the
     World Ocean Circulation Experiment (WOCE), the P6 section began in Valparaiso, Chile, on
     May 2, 1992, and ended 81 days later in Sydney, Australia, on July 30, 1992.  Measurements
     made along WOCE Section P6 included pressure, temperature, salinity [measured by a
     conductivity, temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, silicate,
     nitrate, nitrite, phosphate, radiocarbon (14C), TCO2, and pCO2.
     TCO2 was measured coulometrically by use of two Single-Operator Multiparameter
     Metabolic Analyzers (SOMMAs).  The precision and accuracy of the measurements was
     1.65 mol/kg.  The pCO2 in discrete samples was measured using a headspace-equilibration
     technique and gas chromatography with precision of ~1 to 2%.  The CO2-related measurements
     aboard the R/V Knorr were supported by the U.S. Department of Energy.
     The P6 data set is available free of charge as a numeric data package (NDP) from the
     Carbon Dioxide Information Analysis Center.  The NDP consists of three oceanographic data
     files, three station inventory files, two FORTRAN 90 data retrieval routine files, a readme file,
     and this printed documentation that describes the contents and format of all files as well as the
     procedures and instructions for accessing the data.
     Keywords: carbon dioxide; TCO2; pCO2; coulometry; gas chromatography; World Ocean
     Circulation Experiment; Pacific Ocean; hydrographic measurements; carbon cycle.
               
                                           PART 1: OVERVIEW     
                                     1. BACKGROUND INFORMATION
     The World Ocean Circulation Experiment (WOCE) Hydrographic Program (WHP) was a
     major component of the World Climate Research Program, whose overall goal was to obtain a
     better understanding of the ocean's role in climate and climatic changes resulting from both
     natural and anthropogenic causes.  The need for this experiment arose from the serious concern
     over the rising atmospheric concentrations of carbon dioxide (CO2) and their effect on the heat
     balance of the global atmosphere.  The increasing concentrations of these gases may intensify
     the earth's natural greenhouse effect and alter the global climate in ways that are not well
     understood.  Carbon in the oceans is unevenly distributed because of poorly characterized and
     complex circulation patterns and biogeochemical cycles.  Although total carbon dioxide (TCO2)
     was not an official WOCE measurement, a coordinated effort, supported in the United States
     by the Department of Energy (DOE) and National Oceanic and Atmospheric Administration
     (NOAA), was made on WOCE cruises through 1998 to measure the global spatial and
     temporal distributions of TCO2 and other related parameters.  Goals were to estimate the
     meridional transport of inorganic carbon in a manner analogous to the estimates of oceanic
     heat transport (Bryden and Hall 1980; Brewer et al. 1989; Holfort et al. 1998; Roemmich and
     Wunsch 1985) and to build a database suitable for carbon-cycle modeling and the estimation of
     anthropogenic CO2 increase in the oceans.  The CO2 Survey took advantage of the sampling
     opportunities provided by the WHP cruises during this period, and the final data set is
     expected to cover on the order of 23,000 stations.  Wallace (2001) has recently reviewed the
     goals, conduct, and initial findings of the Joint Global Ocean Flux Study (JGOFS)/WOCE
     Global CO2 Survey.
     This report discusses carbonate system parameters TCO2 and the partial pressure of CO2
     (pCO2) measured aboard the research vessel (R/V) Knorr on the three legs comprising WOCE
     Zonal Section P6.  The section began in Valparaiso, Chile, on May 2, and ended in Sydney,
     Australia, on July 20, 1992, with stops at Easter Island, Chile, and Auckland, New
     Zealand.  The P6 Section was divided into three legs (P6E, P6C, and P6W) and scientists from
     Brookhaven National Laboratory (BNL) were responsible for the carbonate system
     measurements on all of these legs.  The Chief Scientists, scientific crew, and CO2 measurement
     groups from BNL were exchanged after each leg.  Based on the measurements from these
     sections and the data from other Pacific sections occupied during the WOCE Survey (Lamb et
     al. 2001), the large-scale three-dimensional distribution of temperature, salinity, and chemical
     constituents including the carbonate system parameters will be mapped.  Knowledge of these
     parameters and their initial conditions will allow determination of heat and water transports as
     well as carbon transport.  An understanding of these transports will contribute to the
     understanding of processes that are relevant for climate change.
     The work aboard the R/V Knorr was supported by the U.S. DOE under contract DE-
     ACO2-76CH00016.  The authors are grateful to the Sonderforschungsbereich 460 at the
     University of Kiel, which was lead by Dr. F. Schott, and funded by the Deutsche
     Forschungsgemeinschaft, for their support and assistance in completing the written
     documentation.  The authors would also like to acknowledge the invaluable assistance of the
     members of the CO2 measurement group with whom they have lost contact in the years
     intervening since the P6 section was done.  Without the help of Victoria (Nee) Coles, David
     Hunter, and Kevin Wills this work could not have been completed.
                             2. DESCRIPTION OF THE EXPEDITION
     2.1  R/V Knorr:  Technical Details and History
     The R/V Knorr, built in 1969 by the Defoe Shipbuilding Company in Bay City,
     Michigan, is owned by the U.S. Navy.  It was turned over to the Woods Hole Oceanographic
     Institution in 1971 for operation under a charter agreement with the Office of Naval Research
     (ONR).  It was named for E. R. Knorr, a hydrographic engineer and cartographer who in 1860
     held the title of Senior Civilian and Chief Engineer Cartographer of the U.S. Navy Office.  Its
     original length and beam were 245 and 46 feet, respectively.  Beginning on February 6, 1989,
     it underwent a major mid-life retrofit or "jumbo-izing" at the McDermott Shipyard in Amelia,
     Louisiana.  A midsection was added to the ship to stretch its length by 34 feet to 279 feet, and
     fore and aft azimuthing propulsion systems were added to make it one of the most
     maneuverable and stable ships in the oceanographic fleet while on station.  By the time it was
     returned to the Woods Hole Oceanographic Institution in late 1991, the retrofit had consumed
     32 months.  The P6 Section was the first scientific cruise after the retrofitting.  The R/V Knorr
     was designed for a wide range of oceanographic operations, possesses anti-roll tanks and an ice
     strengthened bow, and like its sister ship, the R/V Melville, it is used for ocean research and
     routinely carries scientists from many different countries.  Table 1 provides a list of technical
     characteristics of the R/V Knorr, while Table 2 provides individual cruise information,
     parameter measured, institution, and responsible personnel.
          
       Table 1.  Technical Characteristics of the R/V Knorr
         Ship name:     R/V Knorr
         Call Sign:     KCEJ
         Basic Dimensions:
         Gross registered tonnage   2518 T
         Displacement               2958 lT
         Overall length              279 ft
         Beam                         46 ft
         Draught (maximum)          16.5 ft
         Service speed                12 kn
         Maximum speed              14.5 kn
         Minimum speed               0.1 kn
         Main Deck Clear length      126 ft
         Personnel
         Crew:       24
         Scientists: 34
         Main engine   4 ->  Mak6M 322 = 4  1000 kW at 750 rpm
         Propulsion    Twin Lips diesel-electric, azimuthing stern thrusters, 1500 SHP
         Bow thruster  Lips retractable azimuthing 900 SHP
         Fuel capacity 160,500 gallons
         Maximum cruise duration   60 days (12,000 nm)
         Nautical equipment :      Integrated navigation system
                                   Potable water generator
                                   2 instrument hangars
                                   Winches: 1 heavy duty trawl with 30,000 ft of  inch wire
                                            2 hydrographic, both with 30,000 ft of hydrowire
                                   Hydraulic cranes on the starboard side aft and midships
                                   Scientific storage space of 1,320 ft2
                                   Portable van space
                                   Machine shop
                                   Fume hoods
                                   Uninterruptable power supply
                                   Air conditioning
                                   Library/lounge,
                                   3680 ft2 of laboratory space for multidisciplinary research
     Table 2.  R/V Knorr Cruise Information, Parameter Measured, Institution, and
               Responsible Personnel
                                                         Cruise number
                               138-3 (Leg P6E)           138-4 (Leg P6C)           138-5 (Leg P6W)
     Ports of call           Valparaiso, Chile        Easter Islands, Chile     Auckland, New Zealand
     	                     Easter Islands, Chile    Auckland, New Zealand     Sydney, Australia
    Dates                    May 2-May 26             May 30-July 7             July 13-July 31
    Chief Scientist          Dr. H. Bryden, WHOI      Dr. M. McCartney, WHOI    Dr. J. M. Toole, WHOI
    Parameter                                         Responsible personnel
    ADCP*                    M. Kosro, OSU            M. Kosro, OSU             M. Kosro, OSU
                                                      S. Pierce, OSU            S. Pierce, OSU
    Chilean Observer         S. Marchant, CUV
    Chlorofluorocarbons      R. Weiss, SIO            R. Weiss, SIO             R. Weiss, SIO
    (CFCs)                   K. Sullivan, RSMAS       F. Van Woy, SIO           F. Van Woy, SIO
    CTD**, salinity          H. Bryden, WHOI          M. McCartney, WHOI        J. Toole, WHOI
                             M. Schwartz, WHOI        M. Schwartz, WHOI
    Nutrients                L. Gordon, OSU           L. Gordon, OSU            L. Gordon, OSU
                             A. Ross, OSU             J. Jennings, OSU          J. Jennings, OSU
                             H. Garcia, OSU
    Oxygen                   G. Knapp, WHOI           M.Stalcup, WHOI           G. Knapp, WHOI
    PCO2                     C. Neill, BNL            M. Haines, BNL            V. Coles, BNL
     	                     K. Johnson, BNL          R. Wilke, BNL             K. Johnson, BNL
    Radiocarbon (14C)        R. Key, PU               R. Key, PU                R. Key, PU
     	                     R. Rotter, PU            G. McDonald, PU           G. McDonald, PU
    TCO2                     K. Johnson, BNL          R. Wilke, BNL             K. Johnson, BNL
                             K. Wills, BNL            D. Hunter, BNL            D. Hunter, BNL
    Tritium, Helium          B. Jenkins, WHOI         B. Jenkins, WHOI          B. Jenkins, WHOI
     	                     M. Mathewson, WHOI       S. Birdwhistell, WHOI     M. Mathewson, WHOI
    Underway pCO2            R. Weiss, SIO            R. Weiss, SIO              R. Weiss, SIO
     Participating  institutions:
     Brookhaven National Laboratory, Upton, NY (BNL);
     Commowealth Scientific and Industrial Research Organisation, Australia (CSIRO);
     Catholic University, Valparaiso, Chile (CUV); Oregon State University, Corvallis, OR (OSU);
     Princeton University, Princeton, NJ (PU);
     Rosensteil School of Marine and Atmospheric Science, University of Miami, Miami, FL (RSMAS);
     Scripps Institution of Oceanography, University of California, San Diego, CA (SIO);
     University of Washington, Seattle, WA (UW); and Woods Hole Oceanographic Institution, Woods Hole, MA (WHOI).
     ___________________________________________
     *Acoustic Doppler current profiler.
     **Conductivity, temperature, and depth sensor.
     2.2 Brief Cruise Summary
     The P6 Section really began in mid-April 1992 in Jacksonville, Florida, when BNL
     personnel (K. M. Johnson, R. Ramirez, and R. Wilke) placed two Single-Operator
     Multiparameter Metabolic Analyzers (SOMMA, S/Ns 004 and 006) and a gas chromatograph
     (GC) system for measuring discrete pCO2 aboard the R/V Knorr.  The ship was berthed in
     Jacksonville for the final adjustments following its first shake-down cruise after refitting.
     The BNL CO2 group trucked its scientific gear to Jacksonville to save the cost and trouble of
     shipping it to Chile.  Preliminary operational tests of the measurement systems were made,
     customs declarations filled out, and the instruments were secured for transit to Valparaiso
     before the BNL group departed ship.  The equipment placed on board the ship in Jacksonville
     was used for the entire P6 Section so that subsequent staging was minimal.
     The BNL CO2 group, consisting of K. M. Johnson, C. Neill, and K. Wills, departed New
     York on April 28, 1992, and arrived in Santiago, Chile, on the 29th.  Upon arrival to the pier,
     the R/V Knorr was docking, and the group boarded the ship almost immediately and began the
     testing of the SOMMA and pCO2 GC systems placed aboard in Jacksonville.  A number of
     problems developed during the testing phase.  The SOMMAs were plagued with contamination
     and noise from unknown sources.  Trouble-shooting was interrupted temporarily while a CO2
     group moved aboard the ship on May 1, 1992, and the P6E Leg began with the departure of
     the ship from Valparaiso at 0900 on May 2 under the command of Captain Carl Swanson with
     Harry Bryden as Chief Scientist.
     Trouble-shooting and repair continued, and two serious problems with the SOMMA
     systems were determined.  The first finding was that very brief electrical surges were
     spontaneously causing the 8-port gas sample valve used in the gas calibration procedure to
     attempt to switch from the "load" to the "inject" position.  The surges were not powerful
     enough to cause the valve to actually switch or cause the operator to hear the valve trying to
     switch, but they were strong enough to enable "cross talk" between the valve ports.  Cross-talk
     momentarily connects the calibration gas, in this case pure CO2, to the carrier gas line, and the
     unwanted sporadic introduction of CO2 into the analytical stream interfered with sample
     titrations.  This was only discovered after three very frustrating days by resting the palm of the
     hand on the gas sample valve chassis.  In this way the silent and spontaneous surges could be
     felt through the metal valve cover.  This problem was corrected by placing an uninterruptable
     power supply (UPS) in-line and by unplugging the gas sample valve from the mains when it
     was not needed.  This left a second problem a much smaller, steadier, but still unsatisfactory
     source of noise manifesting itself as an unacceptably high blank.  This noise resulted because
     the carrier gas cylinders of N2 were stored in a hangar external to the laboratory containing the
     SOMMA systems.  Futhermore, thermoplastic lines (in some cases as long as 50 feet) were
     used to connect the cylinders to the SOMMA systems.  These lines apparently allowed enough
     air (containing CO2) to diffuse through the tubing walls, thus interfering with the sample
     titrations.  This problem was corrected by relocating the cylinders within the laboratory to
     within 6 to 10 feet of the SOMMAs.  This relocation along with the installation of the normal
     CO2 scrubbers in the carrier gas lines reduced the blank to satisfactory levels.  The pCO2
     system also got off to a rocky start resulting from some initial software problems that required
     some code to be rewritten.
     The first WOCE CTD station on P6E was station No. 4 with a depth of only 100 m at 32
     30' S and 71 30' W.  Stations 1 through 3 were not included in Section P6E so that there
     were 69 WOCE CTD stations on this leg.  A CO2 group collected samples at 34 of the 69
     stations (~ 50%).  
    Some 1,043 individual water samples along with 98 duplicates and 92 samples for a certified
     reference material (CRM) were analyzed for TCO2.  The pCO2 was determined on 323 of these
     samples.  Because of initial set-up problems, the pCO2 sampling could not begin until
     Station 23.
     As the analytical work proceeded during P6E, the members of the CO2 group became
     aware of an additional problem with one of the SOMMA systems (S/N 004).  In this case, the
     recovery of the CO2 calibration gas during the gas calibration procedure was approximately
     0.2% lower than expected based on prior experience with these systems (99.4 vs 99.6%).  This
     lower recovery was associated with an analytical difference between the measured and CRM
     TCO2 of +3 to -4 mol/kg (measured amount minus certified amount).  This suggested that the
     gas-calibration was in error, however, the problem was identified and corrected.  The relief
     measurement group was asked to bring a spare gas sample valve with them to Easter Island for
     installation at the conclusion of the P6E Leg.
     The ship's operations following the retrofit were not without incident.  In addition to the
     power surges mentioned, at least 2 complete power black-outs were experienced, the ship
     vibrated strongly, and there was noticeable buckling of specific deck plates.  The vibration was
     of particular concern because of the possibility of damage to the computer hard disks.  With
     the exception of the power outages, these problems did not cause any instrumental downtime.
     A lack of fuel availability on Easter Island required conservation measures such as lower ship
     speeds for the P6 Legs.
     The P6E Leg ended with the anchoring of the R/V Knorr at 0800 on May 26, 1992, off
     the village of Hanga Roa on Easter Island.  The first measurement group went ashore after
     lunch and obtained accommodations.  The second measurement group consisting of R. Wilke,
     D. Hunter, and M. Anderson came aboard as the first group left.  They carried with them some
     badly needed replacement parts including a gas sample valve, a refrigerated bath, silver
     electrodes, and fittings.  Change-over between the groups took place on May 28 and 29, and
     the equipment was ready when the ship pulled anchor and departed on Leg P6C on May 30,
     1992, with Mike McCartney as the Chief Scientist.
     The second leg, P6C, which crossed the Southwest Pacific Basins and occupied stations
     from the East Pacific Rise ridge crest to the Kermadec Islands, began with Station 73 which
     was a reoccupation of the last station of the P6E Leg (72).  Both Stations 73 and 74 are co-
     located with Station 72.  The leg continued along 32 30' S from 112 40' W until 178 55' E,
     the location of Station 184.  Thereafter P6C angled northward and ended with Station 188 at
     31 05' S and 177 32' E.  During this leg, additional duplicate stations were made such that
     Station 141 was co-located with 142 and 187 with 188.  The CTD results from station 112 are
     unreliable because of the failure of the CTD.  Of the 113 CTD stations occupied during P6C,
     109 are unique WOCE stations.  The CO2 group collected samples at 51 of the 109 stations
     or 47%.  1739 samples along with 157 duplicates and 162 CRM were analyzed for TCO2.
     Discrete measurements of pCO2 were made on 314 of these samples.
     With respect to the TCO2 systems, the gas sample valve for system 004 was replaced
     before the start of section P6C.  However, the recovery of the CO2 calibration gas did not
     improve, and it remained constant and slightly low (99.4%) as on the first Leg P6E.  No
     additional repairs were attempted.  Otherwise sampling and analysis for the carbonate system
     parameters remained routine.  Unfortunately, of the three legs comprising the P6 Section the
     P6C measurement group experienced the worst weather, and it was the longest of the three
     legs.  The pCO2 system experienced numerous problems indicated by a loss of precision as
     this leg went on.  Modifications were made in coordination with the shore-based BNL
     measurement group members, but precision continued to decline such that the last station run
     on P6C was Station 125 on June 19, 1992.  In addition to poor precision, other problems
     reported included component temperature changes as a result of lack of sufficient insulation
     and traffic through the area where GC was located, exhaustion of the H2 generator's silica gel
     scrubber, unprogrammed gas sample valve switching in the GC (further evidence of electrical
     problems), dirty valve rotors, very rough weather that made trouble-shooting very difficult, and
     finally a thorough cleaning of the GC hardware on June 26 that resulted in the loss of all
     response upon restart.  Daily efforts were made to bring the system back and response was
     gradually restored.  It was not until the Knorr docked in Auckland and replacement parts
     brought by the relief crew were installed that the system was restored to function for the last
     Leg (P6W).  Hence, pCO2 was not determined between Stations 126 and 190.  The P6C
     station work concluded on July 4, and the R/V Knorr arrived at Auckland on July 7.
     The relief crew from BNL, consisting of K. M. Johnson and V. Coles, were joined in
     Auckland by Bronte Tilbrook from the CSIRO Division of Oceanography located in Tasmania,
     Australia.  Change-over and coordination between the relieved and relief groups occurred
     between July 7 and July 9.  Complaints from several sources about the electric power on board
     ship on both Legs P6E and P6C lead to the acquisition and installation of a harmonic filter for
     the ship's "clean power" supply.  Repairs were also made to one of the CTD winches.  The
     ship departed from Auckland to take on fuel for the third and final Leg (P6W) at 0900 on July
     13, 1992, with John Toole as Chief Scientist and Carl Swanson as Master.  At 1600, following
     fueling, the R/V Knorr headed north and picked up where P6C left off with Station 189 which
     is co-located with Stations 188, 187, and 190.  It continued northward to 30 05' S and 176
     30' E.  From 176 30' E the cruise continued along 30 05' S to the Australian coast finishing
     with Station 246 at 153 29' E.  This station was followed by several additional CTD
     calibration stations (247 267) which are not considered or included in the WOCE data sets.
     During P6W, additional duplicate casts were made such that Station 233 is co-located with
     234, Station 246 with 247, and Stations 237 through 246 are co-located with Stations 248
     through 257 and 258 through 267, so that of the 78 CTD stations occupied during P6W, only
     55 represent unique WOCE stations.  The CO2 group collected samples at 22 of these 55
     stations (40%), and 502 water samples along with 47 duplicates and 41 CRM were
     analyzed for TCO2.  Discrete measurements of pCO2 were made on 171 of these samples
     beginning with station 191.  On this leg only one SOMMA (S/N 006) was used.  The station
     work concluded on July 29, and the R/V Knorr arrived in Sydney on July 30, 1992 after
     uniformly good working conditions.
    As on previous cruises, not all stations could be sampled for TCO2 and pCO2 parameters
     because of the lack of the time required for analysis.  With 46% of the P6 stations sampled
     and profiled for TCO2, the goal of 50% coverage was essentially achieved.  The coverage for
     pCO2 was considerably less (25%).  The standard WOCE parameters (temperature, oxygen,
     nutrients, and salinity) were analyzed on all samples, and the carbonate system samples were
     normally drawn in conjunction with the tracer samples which included He, 14C, and the CFCs.
     Sampling frequency was at least every 30 nautical miles, but shorter intervals as a function of
     bathymetry shallow waters or changing depths required more stations were common,
     especially on P6W.  A minimum vertical depth resolution was maintained at 200 m throughout
     the P6 section.  Table 3 presents a summary of the carbonate system measurements made on
     the WOCE section P6.
     Table 3.  The number of stations sampled for carbonate system parameters (CSP) and
       the number of CSP determinations on WOCE Section P6
     ____________________________________________________________________________________
     |  Leg  |          Stations	 |     Number of  CSP  Determinations            |
     |_______|___________________________|_______________________________________________|
     |	     |    CTD  |   CSP  |   %    |   Discrete   |  Duplicate  |  CRM   | Total   |
     |_______|_________|________|________|______________|_____________|________|_________|
                                       TCO2 Measurements
        P6E       68       34       50         1043            98         92       1233
        P6C      109       51       47         1739           157        162       2058
        P6W       55       22       40          502            47         41        590
        Totals	 232*     107       46         3284           302        295       3881
                                       pCO2 Measurements
        P6E       68       21       31          323            27          0        350
        P6C      109       22       20          314            73          0        387
        P6W       55       16       29          171            35          0        206
        Totals	 232*      59       25          808           135          0        943
     ____________________________________________________________________________________
     *Excludes duplicate and test CTD stations.  On the P6C Leg one station (112) was
     thrown out because of a CTD malfunction so severe that the data could not be recovered.
                    3. DESCRIPTION OF VARIABLES AND METHODS
     3.1 Hydrographic Measurements
     Position and depth were manually logged every 10 minutes on the P6 Section.  A
     thermosalinograph (Falmouth Scientific Instruments) was mounted on the bow ~ 3 m below
     the surface and operated on all legs except the latter stages of Leg P6C.  An underway
     fluorometer was operated on Legs P6E and P6C, until it also failed toward the end of Leg P6C
     and was not used again.  Water samples were collected using a 36-position underwater frame
     and 10-L sample bottles designed and constructed by the Ocean Data Facility (ODF) at SIO.
     Modified Neil Brown MkIII CTD instruments mounted on the 36-bottle frame were used for
     data acquisition.  The CTD (Nos. 7, 9, and 10) were supplied by the WHOI Group with No.
     10 being used for the bulk of the work.  CTDs 7 and 9 were used only very sparingly on Leg
     P6C when CTD 10 required electronic repairs.  On the other legs their use was largely
     restricted to test stations.  Small shifts between the pre- and post-cruise pressure and
     temperature CTD calibrations were found, but the P6 CTD data have been corrected according
     to procedures given by Millard et al. (1992), and the CTD salinity data have been empirically
     corrected to conform to the bottle salinity.  The prescribed WOCE sample order was as
     follows: CFCs, helium, oxygen, CO2, nutrients, tritium, and salinity.  Surface currents were
     measured continually during the cruise with a hull-mounted ADCP, and current profiles were
     also made during the CTD casts with an ADCP mounted on the rosette frame.
     Some problems were experienced with the CTD/rosette systems.  The CTD oxygen sensor
     functioned poorly on Leg P6E particularly in the top several 100 m probably because of
     cavitation of a specially installed pump used to circulate water past the sensor.  This pump was
     not used on Legs P6C or P6W.  Problems with the data acquisition software were noted and
     corrected on Leg P6E.  CTD No. 10 failed on Leg P6C at Station 75, and CTD No 9. was
     used through Stations 76-85 while CTD 10 was repaired.  Careful post-cruise verifications
     using the complete bottle data sets have been carried out, and the sample pressures and salinity
     assigned for each sample are to our knowledge correct.
     Bottle salinity was measured on every water sample using 2 Guildline Autosal Model
     8400A salinometers.  The instruments (No. 10 and 11) were furnished by WHOI.  The
     measurements were made in a climate-controlled portable laboratory secured to the deck of the
     ship.  The temperature of the laboratory was kept at 22  1C.  Salinity samples were the last
     water samples drawn from the rosette.  The bottles and caps were rinsed twice and filled to 
     inch of the neck to leave an air space for expansion.  The samples were thermally equilibrated
     in the laboratory before measurement (5-6 h).  The salinometers were standardized with
     International Association for the Physical Sciences of the Ocean (IAPSO) Standard Sea Water
     (Batch P116), and a description of the salinity measurement is given by Knapp et al. (1990).
     Salinometer 11 was used until June 18 when it began to give intermittently higher results
     during the standardization.  From this point on salinometer 10 was used.  The precision of the
     salinity determination was the mean difference between duplicate salinity samples.  For
     samples taken at less than and greater than 3000 m the precision was 0.0012 (n = 107) and
     0.0011 (n = 23), respectively.
     Bottle oxygen was measured on 50-mL aliquots of all P6 water samples by a modified
     Winkler titration technique (Knapp et al. 1990) using a computer-controlled titrator with
     amperometric end-point detection in a constant-temperature laboratory.  Oxygen bottles were
     rinsed twice with sample water and carefully filled to overflowing to avoid air bubbles.  Next
     the reagents were added (1 mL each of the MnCl2 and NaI-NaOH ), and the bottles shaken.
     Following thermal equilibration they were titrated with 0.01 sodium thiosulphate.  The
     precision of the oxygen determination calculated from the mean difference and the standard
     deviation of the mean difference for 121 pairs of duplicate oxygen samples was  0.70 to 
     0.87 mol/kg (n = 98) for depths <3000 m and  0.52 to  0.39 mol/kg (n = 23) for depths
     >3000 m.
     Phosphate, nitrate, nitrite, and silicate were determined on every bottle drawn from
     Stations 3 through 257.  The nutrient concentrations were determined on samples collected in
     high-density polyethylene 30-mL tubes that were directly transferred to an autoanalyzer
     (AlpKem, Model 300 Rapid Flow Analyzer) according to procedures given by anonymous
     (1985) and Gordon et al. (1992; 1994).  Samples were transferred to a climate-controlled
     laboratory and were analyzed within a few hours of collection.  Standards and reagents were
     provided by the OSU group, and working standards (i.e., solutions having nitrate, nitrite,
     phosphate, and silica concentrations similar to those of the Pacific deep and bottom waters)
     were prepared from stock solutions every 4 to 7 days.  Standard and stock solutions were kept
     refrigerated.  Precision was measured by the difference between duplicate samples taken from
     the same rosette bottle analyzed one after the other (not separated in time) or at the start and
     end of the run (separated in time).  Together the differences between replicate analyses is the
     short-term precision, which includes short-term instrumental drift as well as random error.  The
     mean standard deviations or short-term precision for the replicate analyses made on the three
     P6 Legs are: silicic acid 0.16 to 0.035 mol/L; nitrite/nitrate 0.05 to 0.01 mol/L
     phosphate 0.011 to 0.006 mol/L.  Long-term precision was estimated by comparing "old"
     working standard solutions made on the previous station with freshly made working standards
     (i.e., "new" standard solutions made for the current station).  The long-term precision for the
     three P6 Legs are: silicic acid 0.21 to 0.028 mol/L (n = 284); nitrate  0.087 to 0.019
     mol/L (n = 284); phosphate 0.015 to 0.0006 mol/L (n = 241); and nitrate  0.015 to
      0.007 mol/L (n = 284).
     Problems with the nutrient analyses included nonlinearity for the nitrate/nitrite on Leg
     P6E through Station 112 on Leg P6C at which time a plumbing error was discovered and
     corrected.  Post-cruise corrections have been applied to the nitrate/nitrite data through Station
     112.  In addition, the phosphate analysis was lost from Stations 171 through 188 on Leg P6C
     when noise rendered the phosphate channel unusable.  This was corrected in Auckland prior to
     Leg P6W when the air injection phasing board was replaced.
     3.2 Total Carbon Dioxide Measurements
     TCO2 was determined using two automated dynamic headspace sample processors
     (SOMMAs) with coulometric detection of the CO2 extracted from acidified samples.  A
     description of the SOMMA Coulometry System and its calibration can be found in Johnson et
     al. (1987); Johnson and Wallace (1992); and Johnson et al. (1993).  A schematic diagram of
     the SOMMA analytical system and sequence may be found in earlier publications (Johnson et
     al. 1993), and further details concerning the coulometric titration can be found in Huffman
     (1977) and Johnson et al. (1985).  Samples were collected in 300-mL precombusted (450C for
     24 h) glass standard Biological Oxygen Demand (BOD) bottles, poisoned with 200-uL of a
     50% saturated solution of HgCl2, and analyzed for TCO2 within 24 hours of collection (DOE
     Hand Book of Methods, 1994).  Before analysis, they were stored in a refrigerator in darkness
     at ~15C until analyzed.  Analyses of duplicate samples separated in time by up to 8 hours
     showed no evidence of any significant biological consumption or production of CO2 during
     storage under the above conditions.  CRMs were routinely analyzed according to DOE
     prescribed methods (1994).  The CRMs were supplied by Dr. Andrew Dickson of the SIO, and
     during Section P6 batches 10 and 11 were used.  The certified values for batch 10 were S =
     34.5722 and Certified TCO2 = 1960.67  0.39 mol/kg (n = 5).  The corresponding numbers
     for batch 11 were S = 38.5 and TCO2 = 2188.77  0.56 mol/kg (n = 5).  The CRM TCO2
     concentration was determined by Vacuum-Extraction/Manometry in the laboratory of C. D.
     Keeling at SIO.
     Seawater introduced from an automated "to-deliver" pipette into a stripping chamber was
     acidified, and the resultant CO2 from continuous gas extraction was dried and coulometrically
     titrated on a model 5011 UIC Coulometer with a maximum titration current of 50 mA in the
     counts mode [the number of pulses or counts generated by the Coulometer's voltage to
     frequency converter (VFC) during the titration was displayed].  In the coulometer cell, the acid
     (hydroxyethylcarbamic acid) formed from the reaction of CO2 and ethanolamine was titrated
     coulometrically (electrolytic generation of OH-) with photometric endpoint detection.  The
     product of the time and the current passed through the cell during the titration (charge in
     Coulombs) is related by Faraday's constant to the number of moles of OH- generated and thus
     to the moles of CO2 that reacted with ethanolamine to form the acid.  The age of each titration
     cell was logged from its birth (time that electrical current is applied to the cell) until its death
     (time when the current is turned off).  The age was measured in minutes from birth
     (chronological age) and in mgC titrated since birth (carbon age).
     Each system was controlled with an IBM-compatible personal computer equipped with
     two RS232 serial ports (coulometer and barometer), a 24-line digital Input/Output (I/O) card
     (solid state relays and valves), and an Analog to Digital (A/D) card (temperature, conductivity,
     and pressure sensors).  The A/D cards were manufactured by Real Time Devices (State
     College, Pa.).  The temperature sensors (model LM34CH, National Semiconductor, Santa
     Clara, Calif.), with a voltage output of 10 mV/F built into the SOMMA were calibrated
     against thermistors certified to 0.01C (PN CSP60BT103M, Thermometrics, Edison, N.J.)
     using a certified mercury thermometer as a secondary standard.  These sensors monitored the
     temperature of SOMMA components including the pipette, the gas sample loops, and the
     coulometer cell.  The SOMMA software was written in GWBASIC Version 3.20 (Microsoft
     Corp., Redmond, Wash.), and the instruments were driven from an options menu appearing on
     the PC monitor.  Since the coulometers operated in the counts mode, conversions and
     calculations were made using the SOMMA software rather than the programs and the constants
     hardwired into the coulometer circuitry.
     The "to-deliver" volumes (Vcal) of the sample pipettes were determined (calibrated)
     gravimetrically prior to the cruise and were checked periodically during the cruise by
     collecting aliquots of deionized water dispensed from the pipette into preweighed serum
     bottles.  The serum bottles were crimp sealed and weighed immediately during the on-shore
     laboratory calibrations, or were returned to shore and reweighed on a model R300S (Sartorius,
     Gttingen, Germany) balance as soon as possible.  The apparent weight (g) of water collected
     (Wair) was corrected to the mass in vacuo (Mvac) from
                        Mvac = Wair + Wair (0.0012 / d - 0.0012 / 8.0) ,
     where 0.0012 is the sea level density of air at 1 atm, d is the density of the calibration fluid at
     the pipette temperature and sample salinity, and 8.0 is the density of the stainless steel weights.
     The "to-deliver" volume was
                                       Vcal = Mvac / d .
     The calibration volumes (Vcal) at the calibration temperature (tcal) of the SOMMA System
     pipettes for the the three P6 Sections are given in Table 4.
     Table 4.  The "to-deliver" pipette volume (Vcal) and calibration temperature (tcal) for the
               SOMMA-Coulometer systems used on WOCE Section P6
     ___________________________________________________________
     Leg  |  System*   |   Vcal   |   St. Dev.  |   n  |   tcal|
          |            |   (mL)	  |    (mL)     |      |   (C)|
     ___________________________________________________________
      P6E      004       25.5192      0.0069        6    14.93
      P6C      004       25.5195      0.0059        8    15.62
      P6E      006       29.6813      0.0000        2    15.83
      P6C      006       29.6768      0.0045       17    14.86
      P6W      006       29.6668      0.0030        8    14.87
     ____________________________________________________________
     *Note that system 004 was not used during the third Leg P6W.
     The sample volume (Vt) at the pipette temperature was calculated from the expression
                               Vt = Vcal [1 + av (t - tcal)] ,
     where av is the coefficient of volumetric expansion for Pyrex-type glass (1  10^-5/C) and t is
     the temperature of the pipette at the time of a measurement.  Table 4 shows a small decrease
     in Vcal for system 006 over time.  This is consistent with other systems used daily for periods
     exceeding 30 days (Johnson et al. 1998a).  The mean pipette temperature (t) during the P6
     cruise was 15.12  0.41C (n = 3580).
     The Coulometers used to detect CO2 were periodically electronically calibrated as
     described in Johnson et al, (1993, 1996) and DOE (1994) throughout the P6 Section.  For the
     calibration, at least two levels of current (usually 50 and 2 mA) were passed through an
     independent and very precisely known resistance (R) for a fixed time.  The voltage (V) across
     the resistance was continuously measured, and the instantaneous current (I) across the
     resistance was calculated from Ohm's law and integrated over the calibration time.  Then the
     number of pulses (counts) accumulated by the VFC during this time was compared with the
     theoretical number computed from the factory calibration of the VFC [frequency = 105 pulses
     (counts) generated per second at 200 mA] and the measured current.  If the VFC was perfectly
     calibrated at the factory, the electronic calibration procedure would yield a straight line passing
     through the origin with an intercept (Int_ec) of 0 and a slope (Slope_ec) of 1.  The factory-
     calibration of the VFC and the value of the Faraday (96489 Coulomb/mol) yields a scaling
     factor of 4.82445  103 counts/mol, and the theoretical number of micromoles of carbon
     titrated (M) after extraction from water samples or the gas loops was
                      M = [Counts / 4824.45 - (Blank  Tt) - (Int_ec  Ti)] / Slope_ec ,
     where Tt was the length of the titration in minutes, Blank is the system blank in mol/min,
     Intec the intercept in mol/min, and Ti the time in minutes during the titration where current
     flow was continuous.  Note that the slope obtained from the electronic calibration procedure
     applied for the entire length of the titration but the intercept correction applied only for the
     period of continuous current flow (usually 3 to 4 min) because the electronic calibration can
     only be carried out for periods of continuous current flow.  The results of the electronic
     calibrations are given in Table 5.
     Table 5.  Electronic calibration coefficients for SOMMA-Coulometer systems 004 and 006
               on WOCE Section P6
     _______________________________________________________________________
     |Leg   |    System    |    Slope_ec      |     Int_ec   |   Period     |
     |      |              |                  |    mol/min  |              |
     _______________________________________________________________________
      P6E          004          1.000587           0.000049    May 2-May 7
      P6E          004          1.000524           0.000394    May 8-May 18
      P6E          004          0.999905           0.000372    May 19-May 22
      P6E,C        004          0.999708           0.000745    May 23-June 5
      P6C          004          0.999693           0.001237    June 6-June 17
      P6C          004          0.999733           0.001298    June 18-July 6
      P6E          006          0.999567           0.000164    May 2-May 9
      P6E          006          0.999673           0.000017    May 10-May 22
      P6E          006          0.999589           0.000170    May 23-May 30
      P6C          006          0.999708           0.000823    May 31-June 5
      P6C          006          0.999716           0.001146    June 6-June 12
      P6C          006          0.999554           0.001439    June 13-June 28
      P6C          006          0.999638           0.001564    June 29-July 14
      P6W          006          0.999659           0.000339    July 15-July 30
     __________________________________________________________________________
     The SOMMA-Coulometry systems were also calibrated with pure CO2 (calibration gas)
     using hardware consisting of an 8-port gas sampling valve (GSV) with two sample loops of
     known volume (determined gravimetrically by the method of Wilke et al. 1993) connected to
     the calibration gas through an isolation valve with the vent side of the GSV plumbed to a
     barometer.  When a gas loop was filled with CO2, the mass (moles) of CO2 contained therein
     was calculated by dividing the loop volume (V) by the molar volume of CO2 at the ambient
     temperature (T) and pressure (P).  The molar volume of CO2 [V(CO2)] was calculated
     iteratively from T, P, and the first viral coefficient B(T) for pure CO2:
                          V(CO2) = RT / P  (1 + B(T) / V(CO2) .
     The gas calibration factor (CALFAC) the ratio of the calculated mass to that determined
     coulometrically was used to correct the subsequent titrations for small departures from 100%
     recoveries (DOE 1994).  Pressure was measured with a barometer, model 216B-101 Digiquartz
     Transducer (Paroscientific, Inc., Redmond, Wash.) that is factory-calibrated for pressures
     between 11.5 and 16.0 psia.  The standard operating procedure was to make gas calibrations
     daily for each newly prepared titration cell [normally, one cell per day and three sequential
     calibrations per cell at a carbon age of 3 to 6 mgC with the result of the third calibration taken
     as the CALFAC if consistent with the second (i.e., agreement to  0.1% or better)].  The
     CALFAC data for the P6 section are summarized in Table 6.
     Table 6.  The mean gas calibration factors (CALFAC) obtained during the WOCE Section P6
     _____________________________________________________________
     |Leg    |    Cells   |       CALFAC     |     Carbon Age     |
     |       |     (n)	  |    Mean  S.D.   |  Mean  S. D. (MgC)|
     _____________________________________________________________
                 System 004 (CRM-based calibration)
      P6E          21      1.004037  0.000777     10.1  9.3
      P6C          21      1.003932  0.000538     10.9  8.3
                 System 006 (pure-CO2 calibration)
      P6E          24      1.004632  0.000555      5.4  1.6
      P6C          30      1.004535  0.000988      8.5  3.2
      P6W          18      1.004129  0.000755      6.7  1.8
     ______________________________________________________________
     For water samples, the TCO2 concentration in mol/kg was calculated from
                  TCO2  =  M  CALFAC  (1 / (Vt  p))  dHg ,
     where p is the density of seawater in g/mL at the measurement temperature and sample
     salinity calculated from the equation of state given by Millero and Poisson (1981) and dHg is
     the correction for sample dilution with bichloride solution (for P6 dHg = 1.00066).
     As noted above, the daily CALFAC determined for System 004 on the P6E Leg was too
     high (indicating lower recovery of CO2), and when substituted into the last equation it led to
     over-estimates of the CRM TCO2 concentration by 3 to 4 mol/kg (> or = 0.1%).  Unfortunately, the
     cause of this problem was not discovered until a later cruise aboard the R/V Meteor (WOCE
     Section A10) in early 1993 when a leaky plumbing fitting was found and replaced on System
     004 as described by Johnson et al. (1998b).  For convenience, the line carrying the calibration
     gas (CO2) to the GSV had been plumbed (prior to the P6 Section) with a tee connection on the
     upstream side of the GSV with one branch connected to the GSV through an isolation valve
     (IV) and the other branch to a Quick-Connect Fitting (Swagelok, Crawford Fitting).  This
     plumbing configuration facilitated the rapid connection of the calibration gas to an external
     flow-meter and flow rate adjustments, however, the quick-connect fitting apparently allowed a
     very small of amount of air to infiltrate into the calibration gas line slightly diluting the
     calibration gas.  The Quick-Connect and tee fittings were replaced early on the A10 Section
     and System 004 was successfully gas-calibrated thereafter.
     For the P6E and P6C Legs, a "CRM-based calibration factor" was also calculated for
     System 004 by taking the resulting counts for the first CRM analyzed on each cell and
     substituting it along with the certified TCO2 into the last equation and solving it for CALFAC.
     At the end of each leg, a leg-specific mean CRM-based CALFAC was calculated for System
     004, and these data along with the mean CALFAC determined for System 006 are also given
     in Table 6.  The TCO2 measurements from sample analyses made on SOMMA 004 were
     calculated using the mean CRM-based CALFAC shown in Table 7, while TCO2 on SOMMA
     006 was calculated using the CALFAC determined daily using pure-CO2 gas for each new cell
     born according to DOE (1994).
     Taken together, Tables 4 ("to-deliver" pipette volume), 5 (electronic calibration), and 6
     (gas or CRM calibration) show that the response of Systems 004 and 006 remained constant
     throughout the three legs of the P6 Section.  In addition, water samples were collected
     periodically in duplicate and one of the duplicates was analyzed on each system (see Table 4).
     The SOMMA 006 was equipped with a conductance cell (Model SBE-4, Sea-Bird
     Electronics, Inc., Bellevue, Wash.) for the determination of a salinity measurement as
     described by Johnson et al. (1993).  Whenever possible SOMMA and CTD salinity were
     compared to ensure that the salinity of the analyzed samples matched the CTD salinity.  The
     agreement between CTD and SOMMA salinity was 0.04 or better, and several mistrips of the
     Niskin bottles were quickly identified using this comparison.
     Quality Control-Quality Assurance (QC-QA) was assessed from the results of 293 CRM
     analyses made on Systems 004 and 006.  The mean differences between the measured and
     certified TCO2 (measured amount minus certified amount) were calculated for each leg, and
     the mean differences are summarized in Table 7.  The individual differences for the Section P6
     are plotted in Fig. 5 (see online document).
     Table 7.  The mean analytical difference ( TCO2 = measured - certified) and the
               standard deviation of the differences between measured and certified TCO2
               on WOCE Section P6
      _______________________________________________________________
      |Leg    |   System   |   CRM   | delta TCO2  |  St. Dev.  |  n |
      |       |            | (Batch) | (mol/kg)   | (mol/kg)  |    |
      _______________________________________________________________
      P6E          004       10, 11       -0.37         1.37      48
      P6C          004       10, 11       +0.04         1.72      86
      Total/Mean                          -0.11         1.61     134
      P6E          006       10, 11       +0.52         1.35      43
      P6C          006       10, 11       -0.43         1.43      75
      P6W          006       10, 11       -0.54	        1.06      41
      Total/Mean	                  -0.20	        1.39     159
     Overall/Total/Mean	                  -0.16         1.49     293
     ________________________________________________________________
     The accuracy of the CRM analyses was much better than 1 mol/kg on both systems
     throughout the P6 Section, and the overall mean difference is -0.16 mol/kg (n = 293).  The
     precision of the CRM determination on the P6 Section is the standard deviation of the
     difference between determined and certified TCO2 (1.49 mol/kg).  The imprecision of the
     CRM analyses was slightly higher on the P6C Section for both systems, whereas the best
     precision was obtained on the final Leg P6W on System 006.  There were two CRM analyses
     during Section P6 that were considered to be outliers, and these results have not been included
     in Table 7 or Fig. 5.  An outlier was defined as an analytical difference between the measured
     and Certified TCO2 which exceeds 5.0 mol/kg.  The two outliers were measured on System
     006: CRM No. 171 on June 6 at a carbon age of 38.8 mgC; and CRM No. 170 on June 21 at
     an age of 8.6 mgC.  Additional CRMs were analyzed on both cells to within 1 mol/kg of the
     certified TCO2 even at very advanced carbon ages (55.5 and 46.1 mgC, respectively).  Hence,
     the cause of the outlier values was likely not the behavior of the coulometric titration or cell,
     but may have been related to a temporary problem with the sample delivery system (pipette).
     Alternatively, the CRM may have been compromised during preparation or storage.  Sample
     duplication with these cells was observed to be excellent, and accordingly the data obtained
     with them has been included in the data set described herein.
     The second phase of the QC-QA procedure was the assessment of sample precision on
     each system (single-system precision) and the assignment of an overall precision to the P6
     TCO2 samples.  This was the second cruise where two independent SOMMA systems were
     deployed side-by-side, and the conventions employed for the estimation of precision given for
     WOCE Sections A1E and A10 data (Johnson et al. 1996; 1998b) have been retained in
     Table 8.
     Table 8.  Summary of sample precision for TCO2 analyses made during WOCE
               Section P6.
    ___________________________________________________________________________________________
    |        |           Mean Absolute Difference               | The Pooled Standard Deviation|
    |        |__________________________________________________|______________________________|
    | System | sigma(bs) |  S. D.  |  K | sigma(bn)|  S. D.|  K |  Sp2  |   K  |   n  |   d.f. |
    |        |___________|_________|    |__________|_______|____|       |      |      |        |
    |        |       mol/kg       |    |        mol/kg        |mol/kg|      |      |        |
    |________|_____________________|____|_______________________|_______|______|______|________|
                                        Single-System Precision
       004        0.94       0.84    73      0.83      1.19   8    0.89    86     186     100
       006        0.73       0.66   194      0.53      0.53  28    0.71   198     398     202
       All        0.78       0.72   267      0.61      0.71  36    0.76   284     586     302
                                           Sample Precision
       P6         1.90       1.58    24                            1.65    37      74      37
     ___________________________________________________________________________________________
     The single-system precision was determined from samples with duplicates analyzed on the
     same system (either 004 or 006).  The sample precision was calculated using duplicates that
     were analyzed on both systems (004 and 006).
     Single-system and sample precision have been separately assessed in Table 8 as:
     - "between-sample" precision [sigma(bs)] which is the mean absolute difference between
         duplicates (n = 2) drawn from the same Niskin bottle;
     
      - "between-Niskin" precision [sigma(bn)] which was the mean absolute difference between
         duplicates (n = 2) drawn from two different Niskin bottles closed at the same depth;
     
      -  the pooled standard deviation (Sp2) calculated according to Youden (1951) where K
         was the number of samples with duplicates analyzed, n was the total number of
         replicates analyzed from K samples, and n - K was the degrees of freedom (d.f.).
     Single-system precision provides a measure of drift in system response during a sequence
     of sample analyses.  This is because the time elapsed between duplicate analyses on the same
     system using the same coulometer cell was deliberately kept at between 3 and 12 hours.  Any
     temporal drift in system response would therefore be reflected in the single-system precision by
     decreased precision of the duplicate analyses.  Sample precision, on the other hand, provides
     an estimate of overall sample precision for the section(s) independent of which analytical
     system was used.  It was estimated because TCO2 data were measured using two separate
     systems during the cruise.  Sample precision is the most conservative estimate of precision,
     incorporating several sources of random or systematic (bias) error including errors associated
     with the inability to gas calibrate System 004.
     It should be noted that the sample precision calculation includes the results for some
     samples (K = 13) that were analyzed in triplicate (i.e., two replicates analyzed on one system
     and the third on the second system).  For these cases, the mean of the two replicate analyses
     was used for calculating Sp2.  Averaging the replicate results reduced the degrees of freedom
     term by making n = 1 for each system no matter how many replicates were actually run on
     each system.  Without averaging (d.f. = 50), Sp2 was 1.50 mol/kg, whereas with averaging
     (Table 8, d.f. = 37) Sp2 increased to 1.65 mol/kg.  For the P6 Section, the more conservative
     estimate of 1.65 mol/kg was chosen as the precision of the TCO2 determination.  This was
     in excellent agreement with the precision of the CRM determination (1.49 mol/kg).
     As with other sections completed by the BNL measurement group using SOMMA-
     Coulometer systems run in parallel, the sample precision was slightly less precise than the
     single-system precision (1.65 mol/kg vs < 1.0, respectively).  This indicates that any error
     introduced from changes in system response (drift) during the coulometer cell lifetime were
     within the overall precision of the method. The excellent agreement between "between-sample"
     and "between-Niskin" precision suggests that there were no significant analytical effects caused
     by the gas exchange with the overlying headspace of the Niskin bottles during the on-deck
     sampling.  This is consistent with the data collected during other cruises (Johnson et al. 1996;
     1998b).  The P6 sample precision (1.65 mol/kg) was also in good agreement with the
     sample precision for the BNL WOCE Sections A1E (1.65 mol/kg), A10 (1.92 mol/kg),
     A8 (1.17 mol/kg), and the North Atlantic sections (1.59 mol/kg).
     The difference between sample and single-system precision may be the result, in part, of
     the inability to perform daily gas-calibrations on System 004 during P6.  Use of a single
     average CALFAC for an entire leg may, for example, have masked real cell-to-cell variations
     in CALFAC.  This would have the effect of increasing imprecision but not necessarily altering
     overall accuracy (the positive and negative differences would cancel) as is suggested by Table
     9.  Table 9 provides additional proof of the overall accuracy and the absence of a bias between
     the two systems.  Each system yields, within statistical precision, the same result for the same
     samples even though one system (006) was gas-calibrated daily and the other (004) was not
     (see also Tables 6, 7, and 8).  Table 6 shows that the two calibration procedures gave stable
     and nearly identical results during the entire P6 Section.  However, analyzing independent
     water sample duplicates on each system is the definitive test for accuracy, precision,  and the
     calibration procedures used.  The accuracy of System 004 was validated in this way.  This is
     similar to the situation previously described for the A10 Section (Johnson et al. 1998b) where
     only one of the two systems used possessed a gas-calibration unit and the gas-calibrated system
     served as the reference system.
     Table 9.  The mean TCO2 and the mean analytical difference (TCO2 = 006   004) for
               TCO2 from CRM and water samples analyzed on both systems (004 and 006)
               during WOCE Section P6
     ____________________________________________________________________________
    | Comparison  |                         Mean                                 |
    |             |______________________________________________________________|
    |             | System 004 TCO2  | System 006 TCO2  | delta TCO2 (006 - 004) |
    |             |    mol/kg (n)   |    mol/kg (n)   |        mol/kg (n)     |
    |_____________|__________________|__________________|________________________|
     CRM (Batch 10)  1960.63 (59)       1960.24 (73)              -0.39
     CRM (Batch 11)  2188.76 (75)       2188.84 (85)              +0.08
     Water samples   2171.58 (37)       2170.97 (37)              -0.61
     ____________________________________________________________________________
     The final step in the QC-QA procedure was the ship-to-shore comparison.  Here sample
     duplicates (commonly called the "Keeling Samples") were analyzed "in real time" at sea by
     continuous gas extraction/coulometry and later, after shipment and storage, on-shore by
     vacuum extraction/manometry at the laboratory of C. D. Keeling at SIO (Guenther et al. 1994).
     The "Keeling Samples" were collected in specially provided threaded 500-mL glass bottles
     with 4 mL of headspace volume, poisoned with 100 L of a saturated HgCl2 solution, and then
     sealed air-tight with a greased ground glass stopper that was secured to the bottle with a
     threaded plastic screw cap.  The latter was bored out to fit over the top of the stopper and
     mated to the bottle threads so that an air-tight seal was made by gently tightening the cap until
     a secure seal between the stopper and bottle was achieved. This procedure was carried out with
     21 samples collected at 15 stations during P6.  The results of the comparison are given in
     Table 10.
     The mean ship-to-shore analytical difference was -2.64 mol/kg (n = 21).  The lower ship-
     based results for P6 are consistent with the ship-to-shore comparisons from Sections A9, A1E,
     and A10 previously reported (Johnson et al. 1995; 1996; 1998b).  This negative bias for water
     samples was greater than the sample precision and the analytical difference observed for the
     CRM analyses (Wallace 2001).  The reason for the tendency of the ship-based results to be
     lower than the shore-based results is not known at this time.
         In aggregate, Tables 7-10 show an internally consistent data set with excellent accuracy,
     high single-system precision (<1.0 mol/kg), and a slightly higher imprecision for the sample
     precision (1.65 mol/kg).  Based on Tables 7-10 and following the precedent of previous
     data submissions no correction for instrumental bias or CRM analytical differences has been
     applied to the sample data.  Fig. 6 (see omline document) summarizes the analytical results
     as a contour section plot of the TCO2 data from the WOCE Section P6 along 32.5 S.
     Table 10.  Comparison of the shipboard analyses of TCO2 by coulometry and the shore-
                based reference analyses by manometry on duplicate samples.
     (The manometric analyses were completed by February of 1995 in the laboratory of
     C.D. Keeling at SIO)
     _________________________________________________________________________________
    |Station  |  Date | Niskin | Depth | TCO2 (P6) | TCO2 (SIO)  | delta TCO2 (P6-SIO)|
    |         |       |        |  (m)  |  mol/kg  |   mol/kg   |       mol/k       |
    |_________|_______|________|_______|___________|_____________|____________________|
         32      5/12      5    3006.9    2300.19      2302.70          -2.51
         42*     5/15      8    3002.2    2294.39      2301.94          -7.55
         46      5/16     36      18.6    2022.48      2023.65          -1.17
         58      5/20     36       5.4    2016.23      2018.44          -2.21
         58      5/20      5    3002.1    2294.45      2294.34          +0.11
         68      5/23     36      12.2    2014.30      2014.72          -0.42
         68      5/23      1    2771.9    2298.66      2302.19          -3.53
         85      6/04     36      20.3    2010.10(2)** 2014.15          -4.05
         98*     6/08     36      19.2    2015.00(2)   2017.40          -2.40
         98*     6/08      7    2998.1    2298.90      2301.49          -2.59
        123      6/18     35      61.3    2025.20      2027.79          -2.59
        123      6/18     12    3117.9    2305.70      2310.94          -5.24
        144      6/24     35      61.3    2033.70      2036.34          -2.64
        144*     6/24     12    3007.5    2313.10      2316.60          -3.50
        170      7/01     15    3041.2    2288.80      2290.42          -1.62
        184      7/04     23      44.5    2045.50(2)   2049.16          -3.66
        188      7/05     31    3029.0    2309.80      2311.48          -1.68
        231      7/22     24      20.2    2005.20(2)   2009.57          -4.37
        231      7/22      2    3135.3    2269.00      2272.61          -3.61
        233      7/23     10    3001.6    2266.90      2268.49          -1.59
        237      7/24     10    3004.6    2269.30      2267.89          +1.41
     ___________________________________________________________________________________
        Mean                                                            -2.64
        S. D.                                                            1.92
        n                                                                  21
     ___________________________________________________________________________________
     *Analyzed on System 004.
     **Indicates TCO2 is the mean of 2 analyses (the SIO TCO2 values are always the mean of 2
       analyses).
    3.3 Discrete pCO2 Measurements
    Samples for discrete pCO2 analyses were collected by overfilling 60-mL precalibrated
    serum bottles in the same manner as for oxygen and TCO2.  During Section P6 and following
    the static-headspace procedure of Johnson et al. (1990) for CH4, a plastic pipette tip was
    inserted into the bottles making a water-tight seal at the bottle mouth.  Then the bottles were
    inverted so that the volume of water displaced into the pipette was decanted.  Next, the pipette
    was quickly withdrawn and the bottles were crimp-sealed leaving a headspace (gas phase)
    volume in each bottle of (nominally) 5 mL and a liquid phase of (nominally) 55 mL,
    constituting a closed or static system.  The pipette method yields a highly reproducible
    headspace volume, and the headspace and water volume for each (numbered) serum bottle was
    determined gravimetrically prior to the cruise.  The bottles were prepared and sealed outside on
    deck at the CTD site usually within 1 minute of collection.  The atmospheric pressure was
    measured just prior to sealing so that the pre-equilibrated serum-bottle gas phase contained air
    at a known mixing ratio of CO2 (determined regularly throughout the cruise) at a known total
    pressure (P).  The initial liquid phase temperature was taken to be the potential temperature (T)
    of the sample.  The bottles were laid in a thermostatted shaking water bath and equilibrated, by
    shaking, for 3 h at 20C.  After equilibration, the serum-bottle gas phase was displaced by a
    brine solution to flush and fill a gas sample loop whose contents were analyzed by gas
    chromatography.  The mole fraction of CO2 in the gas phase (xCO2eq) was determined after the
    catalytic conversion of CO2 to CH4 with a flame ionization detector through comparison with a
    calibration curve based on CO2 in air standards.  These standards were subsequently
    intercalibrated with standards maintained by Taro Takahashi and Dave Chipman at the Lamont-
    Doherty Earth Observatory (LDEO).
    Erroneously, in the original work (Johnson et al. 1990), no provision was made to measure
    the total gas phase pressure in the serum bottle after equilibration (Peq).  Because Peq was not
    measured during WOCE Section P6, it had to be estimated.  This was done by first calculating
    the moles of N2, O2, and Ar in the liquid phase prior to equilibration using potential
    temperature, the measured O2 concentrations, and by assuming that each water sample was
    saturated at the surface with N2 and Ar with moist air at 1 atm at the potential temperature of
    the sample.  Next, the total number of moles of each gas in the introduced gas phase was
    calculated.  Hence the total number of moles of each gas present in the closed system (serum-
    bottle) was known.  After equilibration, a small correction for glass expansion and the phase
    ratio volume change caused by the change in temperature during equilibration (usually
    warming) was applied.  The partial pressure of each gas at the equilibration temperature (20C)
    was then calculated from the total number of moles for each gas, and these gas partial pressures
    along with the equilibrium partial pressure of water vapor were summed to give Peq in the
    headspace after equilibration.  Then xCO2eq and Peq were multiplied to convert xCO2eq to pCO2
    hereafter called pCO2eq.  Subsequent laboratory tests (C. Neill and D. Wallace, unpublished
    data) confirmed that the serum bottles were not subject to leakage and that the predicted
    pressure closely matched the actual headspace pressure.  The close correspondence between
    measured and predicted headspace pressure has also been confirmed during extensive field tests
    (see Neill et al. 1997).
    TCO2 was measured on an unequilibrated duplicate sample, and the TCO2 of the liquid
    phase after equilibration (repartioning of CO2 between the gas and liquid phases) was calculated
    using a mass balance approach (hereafter designated TCO2eq).  The carbonate alkalinity (CA) of
    the equilibrated sample was calculated using pCO2eq and TCO2eq with the thermodynamic
    constants of Roy et al. (1993) and software developed by Lewis and Wallace (1998).  Because
    carbonate alkalinity is conserved during the equilibration, the derived CA (mol/kg) is the in
    situ value prior to equilibration.  Hence both the in situ TCO2 (measured independently by
    coulometry) and CA are known for each sample prior to the equilibration, and these two
    parameters were used to calculate the sample in situ pCO2 at the equilibration temperature
    using the Lewis and Wallace (1998) software and the Roy et al. (1993) constants.  The pCO2 in
    atm is reported at the equilibration temperature and the equilibration temperature is also
    reported.  Subsequently, the nutrient data became available and Total Alkalinity (TALK) was
    also calculated for each sample according to DOE procedures (1994) using the software given
    by Lewis and Wallace (1998).  TALK values are not reported in this NDP.
    The precision of the pCO2 determination and the TALK calculated from pCO2 and TCO2
    was assessed, when possible, according to the same procedures used for TCO2.   The precision
    of the pCO2 determination and the derived TALK is given in Table 11 as follows:
    - "between-sample" precision [sigma(bs)] for pCO2, which is the mean absolute difference between
       duplicates (n = 2) of K samples drawn from the same Niskin bottle;
    - the pooled standard deviation (Sp2) for pCO2, calculated according to Youden (1951) where
      K was the number of samples with duplicates analyzed (n> or=2), n was the total number of
      replicates analyzed from K samples, and n-K was the degrees of freedom (d.f.);
    - the geometric mean (GM) of the relative standard deviation (Rel. S. D.) for pCO2 from K
      samples with duplicates (n>or=2) analyzed where the Rel. St. Dev. (%) was:
      (S. D. / mean)  100;
    
    - the pooled standard deviation (Sp2) for TALK calculated according to Youden (1951) from
      K pCO2 samples with duplicates analyzed (n>or=2), with n being the total number of TALK
      calculated from K samples with n-K degrees of freedom; and
    
    - the Rel. S. D. (%) for TALK calculated as (Sp2 / mean TALK)  100.
    Table 11. Summary of sample precision for pCO2 and the derived TALK
                       for WOCE Section P6
    ______________________________________________________________________________________
    |Leg  |  sigma(bs) (K)  |  Sp2   | K  |  n  |  d.f. | GM (K) | TALK (Sp2) | Rel. S. D.|
    |     |     (atm)     |(atm) |    |     |       |   (%)  | (mol/kg) |    (%)    |
    |_____|_________________|________|____|_____|_______|________|____________|___________|
      P6E      13.4 (19)       12.8    21    48    27    0.70 (21)    2.36        0.10
      P6C      23.5 (45)       19.8    55   127    72    0.97 (55)    3.82        0.16
      P6W      16.0 (32)       15.2    32    66    34    0.88 (33)    3.08        0.13
      All      19.0 (96)       17.4   109   243   134    0.88 (109)   3.39        0.14
    ______________________________________________________________________________________
    In all, duplicates for 109 of the 808 pCO2 samples were taken during WOCE Section P6.
    Based on these samples, the sample precision (Sp2) for pCO2 was 17.4 atm.  Because of the
    large dynamic range of the pCO2 measurements (>1000 atm), the geometric mean of the Rel.
    S. D. was considered to be the best measure of overall sample precision on a percentage basis
    (0.88%).  For the derived variable TALK, the sample precision (Sp2) was 3.39 mol/kg and
    the Rel. St. Dev. [(Sp2 / mean)  100] was 0.14%.  The corresponding result for TCO2 is
    approximately 0.08%.
    The best precision was found for P6E and the worst for P6C, which is consistent with the
    difficulties for the pCO2 system reported during the P6C cruise.  However, the precision for the
    TALK derived from the pCO2 and the greater imprecision of the TALK determination in
    comparison with the precision of the TCO2 determination, particularly for P6W (factor of 2),
    were consistent with results from other WOCE cruises (Millero et al. 1998).
    3.3.1 Crossover Analysis for pCO2 Measurements Made During WOCE Section P6
    Because the pCO2 method was still under development and because of the instrument
    difficulties experienced during the WOCE Section P6, additional QC-QA assessment was
    required.  Final results of the P6 pCO2 analyses were checked by comparing the deep water
    results with those obtained on other WOCE cruises that intersected the P6 line.  With this test
    it was assumed that deep and bottom water results have not changed at a given location over
    the relatively short time interval of a few years separating the different cruises.
    The stations selected for each crossover are those which are close to the crossover point
    and on which carbon measurements were made.  The number of stations selected was
    somewhat subjective but was such that sufficient measurements were present for the analysis
    without getting too far away from the crossover location.  In all cases the stations were within
    approximately 1 of latitude and longitude of the crossover point.  Table 12 lists the stations
    used for each crossover.
    Once the stations were chosen the results were plotted against potential density referenced
    to 3000 dbar (sigma3).  Only data from pressures greater than 2500 dbar were included in order to
    minimize the influence of possible lateral gradients.  A smooth curve was fitted to the
    combined station data from each leg so long as there were seven or more data points that could
    be used for the fit.  The fitting curve chosen was a "robust loess" function designed to
    minimize the influence of outliers (Feely et al. 1999).  In cases having fewer than 7 points,
    linear segments were used to "connect the dots."  Only data which had been marked with a
    quality control flag of 2 (good) or 6 (replicate) were included in the analyses.  Reported pCO2
    results were converted to fCO2 using the Weiss function (Weiss 1974) and the measured
    temperature prior to the comparison.  fCO2 values are not reported in this NDP.
    In order to quantitatively estimate the mean difference between legs, each of the two fitted
    curves was evaluated at 50 evenly spaced intervals covering the range of space common to the
    selected stations from both legs.  The 50 differences were then averaged.  Table 12 summarizes
    the mean differences and standard deviations for each crossover, and indicates the differences
    in terms of the cruise leg designations.
        Table 12.  WOCE Section P6 fCO2 crossover results
        __________________________________________________________________________
        |Crossover      Cruise 1    Stations   Cruise 2    Stations    Differences|
        |   no.*                                                                  |
        |_________________________________________________________________________|
             66a        P16S/P17S      179        P6W         108        6.7  8.6
             66c        P16A/P17A      119        P6W         108        7.6  11.3
             76            P18          73        P6E        56, 58    -12.9  6.4
             81           P19C         299        P6E      32, 34, 36    3.6  7.3
        ___________________________________________________________________________
    *Crossover number taken from the Global Ocean Data Analysis Project (GLODAP) list for the entire
     Pacific Ocean (Lamb et al. 2001).
    Samples from one of the intersecting cruises, P18, were analyzed by Rik Wanninkhof of
    the Atlantic Oceanographic and Meteorological Laboratory while the other three were analyzed
    by scientists from Taro Takahashi's group of LDEO.  Previous crossover tests have indicated
    that the P18 fCO2 results may be somewhat low as a result of minor sample loss, and the
    checks preformed at CDIAC tend to support that finding.  Differences between the P6 results
    and those measured by the LDEO group are well within the precision (Table 12) of the
    technique.
    Based on these checks, the prototype pCO2 method appears to have performed adequately,
    and no additional corrections to the pCO2 data have been made.  Nevertheless, the P6 Section
    work showed that the pCO2 method could be improved.  Before the next deployment in 1994,
    the pCO2 method incorporated automated and highly accurate measurements of P, Peq, and
    analytical temperatures throughout, rigorous control of the phase volume ratio and the
    headspace gas composition prior to equilibration, and new software (Neill et al. 1997).
    Figure 7 (see online document) summarizes the analytical results as a contour section plot of
    the pCO2 data from the WOCE Section P6.
    3.4 Radiocarbon Measurements
         During the R/V Knorr expedition along WOCE Section P6, 649 accelerator mass
    spectrometry (AMS) delta 14C samples were collected at 30 stations.  In addition 17 replicate
    measurements of 14C were performed.  Sampling of 14C during the cruise was carried out by the
    scientists from the Ocean Tracer Laboratory at Princeton University, with R. Key as the
    principal investigator for these data.  For a detailed description of the methods and
    instrumentation used for 14C measurements please read the reprint of pertinent literature: "P6
    Final Report for AMS 14C Samples" in Appendix A of omline documentation or hard copy.
    4. DATA CHECKS AND PROCESSING PERFORMED BY CDIAC
    An important part of the numeric data packaging 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 data obtained during the R/V Knorr cruise along WOCE Section P6 in the
    South Pacific Ocean.
    1. The final carbon-related data were provided to CDIAC by D. W. R. Wallace and K. M.
       Johnson of Brookhaven National Laboratory.  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 90 retrieval code was
       written and used to merge and reformat all data files.
    2. To check for obvious outliers, all data were plotted by use of 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. 8-13 in online doc.).
       Several outliers were identified and marked with the quality flags of "3" (questionable
       measurement) or "4" (bad measurement) (see File Descriptions in Part 2 of this
       documentation).
    3. To identify "noisy" data and possible systematic, methodological errors, property-property
       plots for all parameters were generated (Fig. 14 in online documentation), carefully examined,
       and compared with plots from previous expeditions in the Pacific Ocean.
    4. All variables were checked for values exceeding physical limits, such as sampling depth
       values that are 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; LATITUDE
       <  25.000 or >  32.000; LONGITUDE < 150.000 or >  80.000.
    6. Station locations (latitudes and longitudes) and sampling times were examined for
       consistency with maps and cruise information supplied by D. W. R. Wallace and K. M.
       Johnson of BNL.
    7. The designation for missing values, given as  9.0 in the original files, was changed to
       999.9 for the consistency with other oceanographic data sets.
           5.  HOW TO OBTAIN THE DATA AND DOCUMENTATION
    This database (NDP-077) 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 160.91.18.18
            Login: "anonymous" or "ftp"
            Password: your e-mail address
            ftp> cd pub/ndp077/
            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
    Anonymous.  1985.  RFA-300 Rapid Flow Analyzer Operation Manual.  Alpkem Corporation,
             Clackamas, Oregon, U.S.A.
    Brewer, P. G., C. Goyet, and D. Dyrssen.  1989.  Carbon dioxide transport by ocean currents
             at 25 N latitude in the Atlantic Ocean.  Science 246:477-79.
    Bryden, H. L., and M. M. Hall.  1980.  Heat transport by ocean currents across 25 N latitude
             in the North Atlantic Ocean.  Science 207:884.
    DOE (U.S. Deapartment of Energy).  1994.  Handbook of Methods for the Analysis of the
             Various Parameters of the Carbon Dioxide System in Sea Water. Version 2.0.
             ORNL/CDIAC-74.  A. G. Dickson and C. Goyet (eds.). Carbon Dioxide Information
             Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A.
    Feely, R. A., M. F. Lamb, D. J. Greeley, and R. Wanninkhof.  1999.  Comparison of the
             carbon system parameters at the global CO2 survey crossover locations in the North and
             South Pacific Ocean, 1990 1996. ORNL/CDIAC-115. Carbon Dioxide Information
             Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge,
             Tennessee, U.S.A.
    Gordon, L. I., J. C. Jennings, Jr., A. A. Ross, and J. M. Krest.  1992.  A suggested protocol for
             continuous flow automated analysis of seawater nutrients (phosphate, nitrate, nitrite and
             silicic acid) in the WOCE Hydrographic Program and the Joint Global Ocean Fluxes
             Study. Grp. Tech. Rpt. 92-1.  Chemical Oceanography Group, Oregon State University,
             College of Oceanography, Oregon, U.S.A.
    Gordon, L. I., J. C. Jennings, Jr., A. A. Ross, and J. M. Krest.  1994.  A suggested protocol for
             continuous flow automated analysis of seawater nutrients (phosphate, nitrate, nitrite and
             silicic acid) in the WOCE Hydrographic Program and the Joint Global Ocean Fluxes
             Study.  In WOCE Operations Manual.  WHP Office Report WHPO 91-1. WOCE Report
             No. 68/91.  Revision 1. Woods Hole, Mass., U.S.A.
    Guenther, P. R., C. D. Keeling, and G. Emanuele.  1994.  Oceanic CO2 measurements for the
             WOCE hydrographic survey in the Pacific Ocean, 1990-1991: Shore based analyses. SIO
             Reference Series, No. 94-28.  Scrips Institution of Oceanography, University of California
             San Diego, La Jolla, California, U.S.A.
    Holfort, J., K. M. Johnson, B. Schneider, G. Siedler, and D. W. R. Wallace.  1998.  Meridional
             transport of dissolved inorganic carbon in the South Atlantic Ocean.  Global
             Biogeochemical Cycles. 12:479-99.
    Huffman, E. W. D., Jr.  1977.  Performance of a new automatic carbon dioxide coulometer.
             Microchemical Journal 22:567-73.
    Johnson, K. M., A. E. King, and J. McN. Sieburth.  1985.  Coulometric TCO2 analyses for
             marine studies:  An introduction.  Marine Chemistry 16:61-82.
    Johnson, K. M., P. J. Williams, and L. Brandstroem, and J. McN. Sieburth.  1987.
             Coulometric  TCO2 analysis for marine studies:  Automation and calibration.  Marine
             Chemistry 21:117-33.
    Johnson, K. M., J. E. Hughes, P. L. Donaghay, and J. McN. Sieburth.  1990.  Bottle-calibration
             static head space method for the determination of methane dissolved in seawater.
             Analitical Chemistry 62:2408-12.
    Johnson, K. M., and D. W. R. Wallace.  1992.  The single-operator multiparameter metabolic
             analyzer for total carbon dioxide with coulometric detection.  DOE Research Summary
             No.  19.  Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory,
             Tenn., U.S.A.
    Johnson, K. M., K. D. Wills, D. B. Butler, W. K. Johnson, and C. S. Wong.  1993.
             Coulometric  total carbon dioxide analysis for marine studies: Maximizing the
             performance of an automated gas extraction system and coulometric detector. Marine
             Chemistry 44:167-87.
    Johnson, K. M., D. W. R. Wallace, R. J. Wilke, and C. Goyet.  1995.  Carbon dioxide,
             hydrographic, and chemical data obtained during the R/V Meteor Cruise 15/3 in the South
             Atlantic Ocean (WOCE Section A9, February March 1991).  ORNL/CDIAC-82,
             NDP-051.  Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory,
             Oak Ridge, Tenn., U.S.A.
    Johnson, K. M., B. Schneider, L. Mintrop, and D. W. R. Wallace.  1996.  Carbon dioxide,
             hydrographic, and chemical data obtained during the R/V Meteor Cruise 18/1 in the North
             Atlantic Ocean (WOCE Section A1E, September 1991).  NDP-056.  Carbon Dioxide
             Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn., U.S.A.
    Johnson, K. M., A. G. Dickson, G. Eischeid, C. Goyet, P. R. Guenther, R. M. Key, F. J.
             Millero, D. Purkerson, C. L. Sabine, R. G. Schotle, D. W. R. Wallace, R. J. Wilke, and
             C. D. Winn.  1998a.  Coulometric total carbon dioxide analysis for marine studies:
             Assessment of the quality of total inorganic carbon measurements made during the U.S.
             Indian Ocean CO2 Survey 1994 1996.  Marine Chemistry 63:21-37.
    Johnson, K. M., B. Schneider, L. Mintrop, and D. W. R. Wallace.  1998b.  Carbon dioxide,
             hydrographic, and chemical data obtained during the R/V Meteor Cruise 22/5 in the South
             Atlantic Ocean (WOCE Section A10, December 1992 January 1993).  NDP-066.  Carbon
             Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn.,
             U.S.A.
    Knapp, G. P., M. C. Stalcup, and R. J. Stanley.  1990.  Automated oxygen and salinity
             determination.  WHOI Technical Report No. WHOI-90-35.  Woods Hole Oceanographic
             Institution, Woods Hole, Mass., U.S.A.
    Lamb, M. F., C. L. Sabine, R. A. Feely, R. Wanninkhof, R. M. Key, G. C. Johnson, F. J.
             Millero, K. Lee, T.-H. Peng, A. Kozyr, J. L. Bullister, D. Greeley, R. H. Byrne, D. W.
             Chipman, A. G. Dickson, C. Goyet, P. R. Guenther, M. Ishii, K. M. Johnson, C. D.
             Keeling, T. Ono, K. Shitashima, B. Tilbrook, T. Takahashi, D. W. R. Wallace,
             Y. Watanabe, C. D. Winn, and C. S. Wong.  2001.  Consistency and synthesis of Pacific
             Ocean CO2 survey data, Deep-Sea Research (in press).
    Lewis, E. and D. W. R. Wallace.  1998.  Program developed for CO2 system calculations.
             ORNL/CDIAC-105. Carbon Dioxide Information Analysis Center, Oak Ridge National
             Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.
    Millard, R., G. Boud, and J. Toole.  1992.  Implementation of a titanium strain gauge pressure
             transducer for CTD applications. Deep-Sea Research 15:1009-21.
    Millero, F. J., and A. Poisson.  1981.  International one-atmosphere equation of state for sea
             water.  Deep-Sea Research 28:625-29.
    Millero, F. J., A. G. Dickson, G. Eischeid, C. Goyet, P. R. Guenther, K. M. Johnson, K. Lee,
             E. Lewis, D. Purkerson, C. L. Sabine, R. Key, R. G. Schottle, D. R. W. Wallace, and
             C. D. Winn.  1998.  Total alkalinity measurements in the Indian Ocean during the WOCE
             hydrographic program CO2 survey cruises 1994 1996.  Marine Chemistry 63:9-20.
    Neill, C., K. M. Johnson, E. Lewis, and D. W. R. Wallace.  1997.  Accurate headspace analysis
             of fCO2 in discrete water samples using batch equilibration.  Limnology & Oceanography
             42:1774-83.
    Roemmich, D., and C. Wunsch.  1985.  Two transatlantic sections: Meridional circulation and
             heat flux in the subtropical North Atlantic Ocean.  Deep Sea Research 32:619-64.
    Roy, R. N., L. N. Roy, K. M. Vogel, C. Porter-Moore, T. Pearson, C. E. Good, F. J. Millero,
             and D. M. Campbell.  1993.  The dissociation constants of carbonic acid in seawater at
             salinities 5 to 45 and temperatures 0 to 45C.  Marine Chemistry 44:249-67.
    Schlitzer, R.  2001.  Ocean Data View.  http://www.awi-bremerhaven.de/GEO/ODV. Online
             publication.  Alfred-Wegener-Institute for Polar and Marine Research. Bremerhaven,
             Germany.
    Wallace, D. W. R.  2001.  Storage and transport of excess CO2 in the oceans: The
             JGOFS/WOCE Global CO2 Survey.  In J. Church, G. Siedler, and J. Gould (eds.)., Ocean
             Circulation and Climate,  Academic Press, (in press).
    Weiss, R. F.  1974.  Carbon dioxide in water and seawater: The solubility of a non-ideal gas.
             Marine Chemistry 2:203-15.
    Wilke, R. J., D. W. R. Wallace, and K. M. Johnson.  1993.  A water-based, gravimetric method
             for the determination of gas sample loop volume.  Analitical Chemistry 65:2403-06.
    Youden, W. J.  1951.  Statistical Methods for Chemists.  Wiley, New York.
                            PART 2:
                   CONTENT AND FORMAT OF DATA FILES    
                   7. FILE DESCRIPTIONS
    This section describes the content and format of each of the nine files that comprise this
    NDP (see Table 13).  Because CDIAC distributes the data set in several ways (via the Web,
    CDIAC's online ordering system, or anonymous FTP), each of the nine files is referenced by
    both an ASCII file name, which is given in lowercase, bold-faced type (e.g., ndp077.txt), and a
    file number.  The remainder of this section describes (or lists, where appropriate) the contents
    of each file.
      Table 13.  Content, size, and format of data files
      File number, name,                                      Logical                    File size
      and description                                         records                     in bytes
    1. ndp077.txt:                                             1,881                      118,354
       a detailed description of the cruise network,
       the two FORTRAN 90 data-retrieval routines,
       and the six oceanographic data files
    2. stainv.for:                                                45                        1,337
       a FORTRAN 90 data-retrieval routine to read and
       print p6esta.dat (File 4), p6csta.dat (File 5), and
       p6wsta.dat (File 6)
    3. p6ecwdat.for:                                              54                        2,242
       a FORTRAN 90 data-retrieval routine to read and
       print p6e.dat (File 7), p6c.dat (File 8), and
       p6w.dat (File 9)
  4-6. p6esta.dat, p6csta.dat, p6wsta.dat:                        82                        6,146
       a listing of the station locations, sampling dates,       124                        9,338
       and sounding bottom depths for each station of the         90                        6,754
       WOCE Sections P6E, P6C, and P6W
  7-9. p6e.dat, p6c.dat, p6w.dat:                              2,353                      412,952
       hydrographic, carbon dioxide, and chemical data         3,982                      699,656
       from all stations occupied on WOCE Sections P6E,        1,564                      274,088
       P6C, and P6W
                                                              ______                    _________
       Total                                                  10,175                    1,530,867
    7.1 ndp077.txt (File 1)
    This file contains a detailed description of the data set, the two FORTRAN 90 data-
    retrieval routines, and the six 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 90 data-retrieval routine to read and print p6*sta.dat
    (Files 4-6).  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 p6*sta.dat in Sect. 7.4.
    c********************************************************************
    c* FORTRAN 90 data retrieval routine to read and print the files
    c* named "p6*sta.dat" (File 4-6).
    c********************************************************************
    c*Defines variables*
           INTEGER  stat, cast, depth
           REAL latdcm, londcm
           CHARACTER expo*9, sect*4, date*10, time*4
           OPEN (unit=1, file='p6*sta.dat')
           OPEN (unit=2, file='p6*.sta')
           write (2, 5)
    c*Writes out column labels*
     5     format (1X,'EXPOCODE',3X,'SECT',1X,'STNBR',2X,'CAST',9X,
         3 'DATE',2X,'TIME',2X,'LATITUDE',2X,'LONGITUDE',2X,
         4 '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 (A9, 3X, A4, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 3X,
         1 F7.3, 3X, F8.3, 3X, I4)
           write (2, 20) expo, sect, stat, cast, date, time,
         1 latdcm, londcm, depth
     20    format (A9, 3X, A4, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 3X,
         1 F7.3, 3X, F8.3, 3X, I4)
           GOTO 7
     999   close(unit=5)
           close(unit=2)
           stop
           end
    7.3 p6ecwdat.for (File 3)
    his file contains a FORTRAN 90 data-retrieval routine to read and print p6*.dat
    (Files 7-9).  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 p6*.dat in Sect. 7.5.
    c********************************************************************
    c* FORTRAN 90 data retrieval routine to read and print the files
    c* named "p6*.dat" (Files 7 9).
    c********************************************************************
    c*Defines variables*
           CHARACTER qualt*12, bot*7
           INTEGER sta, cast, samp
           REAL pre, ctdtmp, ctdsal, ctdoxy, theta, sal, oxy, silca
           REAL nitrat, nitrit, phspht, dc14, c14er, tco2, pco2, pco2tmp
           OPEN (unit=1, file='p6e.dat')
           OPEN (unit=2, file='p6e.data')
           write (2, 5)
    c*Writes out column labels*
     5     format (2X,'STNNBR',2X,'CASTNO',2X,'SAMPNO',2X,'BTLNBR',
         1 2X,'CTDPRS',2X,'CTDTMP',2X,'CTDSAL',2X,'CTDOXY',3X,'THETA',
         2 4X,'SALNTY',2X,'OXYGEN',2X,'SILCAT',2X,'NITRAT',2X,'NITRIT',
         3 2X,'PHSPHT',2X,'DELC14',2X,'C14ERR',2X,'TCARBN',4X,'PCO2',1X,
         4 'PCO2TMP',7X,'QUALT1',/,36X,'DBAR',2X,'ITS-90',2X,'PSS-78',
         5 1X,'UMOL/KG',2X,'ITS_90',4X,'PSS-78',1X,5('UMOL/KG',1X),
         6 1X,'/MILLE',2X,'/MILLE',1X,'UMOL/KG',4X,'UATM',3X,'DEG_C',12X,
         7 '*',/,25X,'*******',17X,2('*******',1X),10X,7('*******',1X),
         8 8X,2('*******',1X),19X,'*')
    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, dc14, c14er, tco2, pco2, pco2tmp, qualt
     10    format (5X, I3, 7X, I1, 6X, I2, 1X, A7, 1X, F7.1, 1X, F7.4,
         1 1X, F7.4, 1X, F7.1, 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, F7.1,
         3 1X, F7.1, 1X, F7.1, 1X, A12)
           write (2, 20) sta, cast, samp, bot, pre, ctdtmp,
         1 ctdsal, ctdoxy, theta, sal, oxy, silca, nitrat, nitrit,
         2 phspht, dc14, c14er, tco2, pco2, pco2tmp, qualt
     20    format (5X, I3, 7X, I1, 6X, I2, 1X, A7, 1X, F7.1, 1X, F7.4,
         1 1X, F7.4, 1X, F7.1, 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, F7.1,
         3 1X, F7.1, 1X, F7.1, 1X, A12)
           GOTO 7
     999   close(unit=1)
           close(unit=2)
           stop=2)
           stop
           end
    7.4 p6*sta.dat (Files 4-6)
    These files, p6esta.dat, p6csta.dat, and p6wsta.dat, provide station inventory information
    for each station occupied during the R/V Knorr cruise along WOCE Sections P6E, P6C, and
    P6W.  Each line in the files contains an expocode, section number, station number, cast
    number, sampling date (month/date/year), sampling time, latitude, longitude, and sounding
    depth.  The files are sorted by station number and can be read by using the following
    FORTRAN 90 code (contained in stainv.for, File 2):
           INTEGER stat, cast, depth
           CHARACTER expo*9, sect*4, date*10, time*4
           REAL latdcm, londcm
           read (1, 10, end=999) expo, sect, stat, cast, date, time,
         1 latdcm, londcm, depth
     10    format (A9, 3X, A4, 3X, I3, 5X, I1, 3X, A10, 2X, A4, 3X,
         1 F7.3, 3X, F8.3, 3X, I4)
    Stated in tabular form, the contents include the following:
    Variable             Variable     Variable        Starting     Ending
                           type         width          column      column
      expo               Character        9               1           9
      sect               Character        4              13          16
      stat                Numeric         3              20          22
      cast                Numeric         1              28          28
      date               Character       10              32          41
      time               Character        4              44          47
      latdcm              Numeric         7              51          57
      londcm              Numeric         8              61          68
      depth               Numeric         4              72          75
    The variables are defined as follows:
    expo       is the 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 p6*.dat (Files 7-9)
    These files, p6e.dat, p6c.dat, and p6w.dat, provide hydrographic, carbon dioxide, and
    chemical data for all stations occupied during the R/V Knorr cruise along WOCE Sections
    P6E, P6C, and P6W.  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, bottle oxygen, silicate, nitrate, nitrite, phosphate, del14C,
    del14C error, TCO2, pCO2, pCO2 temperature, and data-quality flags.  The files are sorted
    by station number and pressure and can be read by using the following FORTRAN 90 code
    (contained in p6ecwdat.for, File 3):
           CHARACTER qualt*12, bot*7
           INTEGER sta, cast, samp
           REAL pre, ctdtmp, ctdsal, ctdoxy, theta, sal, oxy, silca
           REAL nitrat, nitrit, phspht, dc14, c14er, tco2, pco2, pco2tmp
           read (1, 10, end=999) sta, cast, samp, bot, pre, ctdtmp,
         1 ctdsal, ctdoxy, theta, sal, oxy, silca, nitrat, nitrit,
         2 phspht, dc14, c14er, tco2, pco2, pco2tmp, qualt
     10    format (5X, I3, 7X, I1, 6X, I2, 1X, A7, 1X, F7.1, 1X, F7.4,
         1 1X, F7.4, 1X, F7.1, 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, F7.1,
         3 1X, F7.1, 1X, F7.1, 1X, A12)
    Stated in tabular form, the contents include the following:
                       Variable      Variable       Starting     Ending
    Variable             type         width          column      column
    sta                 Numeric          3               6           8
    cast                Numeric          1              16          16
    samp                Numeric          2              22          24
    bot                Character         7              26          32
    pre                 Numeric          7              34          40
    ctdtmp              Numeric          7              42          48
    ctdsal              Numeric          7              50          56
    ctdoxy              Numeric          7              58          64
    theta               Numeric          7              66          72
    sal                 Numeric          9              74          82
    oxy                 Numeric          7              84          90
    silca               Numeric          7              92          98
    nitrat              Numeric          7             100         106
    nitrit              Numeric          7             108         114
    phspht              Numeric          7             116         122
    dc14                Numeric          7             124         130
    c14er               Numeric          7             132         138
    tcarb               Numeric          7             140         146
    pco2                Numeric          7             148         154
    pco2tmp             Numeric          7             156         162
    qualt              Character        12             164         175
    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);
    dc14*      is the radiocarbon delta 14C (per mille);
    c14er      is the error of delta 14C (percent);
    tcarb*     is the total carbon dioxide concentration (mol/kg);
    pco2*      is the partial pressure of CO2 (atm);
    pco2tmp    is the temperature of equilibration of the pCO2 samples in equilibrator (C);
    qualt      is a 14-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.
                           APPENDIX A:
                 REPRINT OF PERTINENT LITERATURE
               (in online or printed documentation)