ORNL/CDIAC-91 NDP-056 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) Contributed by Kenneth M. Johnson*, Bernd Schneider**, Lutger Mintrop***, and Douglas W. R. Wallace*, *Brookhaven National Laboratory Upton, New York, U.S.A. **Institut fur Ostseeforschung Rostock-Warnemunde, Germany ***Institut fur Meereskunde Kiel, Germany Prepared by Alexander Kozyr**** Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Oak Ridge, Tennessee, U.S.A. ****Energy, Environment, and Resources Center The University of Tennessee, Knoxville, Tennessee, U.S.A. Environmental Sciences Division Publication No. 4543 Date Published: July 1996 Prepared for the Global Change Research Program Environmental Sciences Division Office of Health and Environmental Research U.S. Department of Energy Budget Activity Numbers KP 05 02 00 0 and KP 05 05 00 0 Prepared by the Carbon Dioxide Information Analysis Center OAK RIDGE NATIONAL LABORATORY Oak Ridge, Tennessee 37831-6335 managed by LOCKHEED MARTIN ENERGY RESEARCH CORP. for the U.S. DEPARTMENT OF ENERGY under contract DE-AC05-96OR22464 ABSTRACT 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). ORNL/CDIAC-91, NDP-056. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tennessee. The North Atlantic Ocean is characterized by an intense meridional circulation cell carrying near-surface waters of tropical and subtropical origin northward and deep waters of arctic and subarctic origin southward. The related overturning is driven by the sinking of water masses at high latitudes. The overturning rate and thus the intensity of the meridional transports of mass, heat, and salt, is an important control parameter for the modeling of the ocean's role in climate. Certainly such estimates require more than one survey of the study area; therefore, the Research Vessel (R/V) Meteor Cruise 18/1 was one in a series of cruises in North Atlantic that started in March 1991 and continued until 1995 (Meincke 1993). This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO2) and total alkalinity (TALK) at hydrographic stations, as well as underway partial pressure of CO2 (pCO2) measured during the R/V Meteor Cruise 18/1 in the North Atlantic Ocean (Section A1E). Conducted as part of the World Ocean Circulation Experiment (WOCE) and North Atlantic Overturning Rate Determination, the cruise began in Reykjavik, Iceland, on September 2, 1991, and ended after 24 days at sea in Hamburg, Germany, on September 25, 1991. WOCE Zonal Section A1E began at 60 N and 42 30' W (southeast of Greenland) and continued southeast with a closely spaced series of hydrocasts to 52 20' N and 14 15' W (Porcupine Shelves). Measurements made along WOCE Section A1E included pressure, temperature, salinity, and oxygen measured by a conductivity, temperature and depth (CTD) sensor; bottle salinity; oxygen; phosphate; nitrate; nitrite; silicate; TCO2; TALK; and underway pCO2. A total of 61 CTD casts were made, including 59 bottle casts and 2 calibration stations. Replicate samples from seven Niskin bottles at five stations were also collected for later shore-based reference analyses of TCO2 and TALK by vacuum extraction and manometry in the laboratory of Dr. Charles D. Keeling, Scripps Institution of Oceanography; these results are also included in this report. TCO2 was measured by using an automated sample processor, to extract CO2 from seawater samples, coupled to a coulometer, to detect the extracted gas. The precision and accuracy of the system was +/-1.60 umol/kg. Samples collected for TALK were measured by using standard potentiometric techniques; precision was +/-2.0 umol/kg. Underway pCO2 was measured by infrared photometry; precision was +/-2 uatm. The R/V Meteor Cruise 18/1 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 FORTRAN 77 data retrieval routine files, a documentation file, and this printed documentation, which describes the contents and format of all files as well as the procedures and methods used to obtain the data. Keywords: carbon dioxide; World Ocean Circulation Experiment; North Atlantic Ocean; hydrographic measurements; nutrient measurements; carbon cycle PART 1: OVERVIEW 1. BACKGROUND INFORMATION To better understand the ocean's role in climate and climatic changes, several large experiments have been conducted in the past, and others are currently under way. The World Ocean Circulation Experiment (WOCE) is a major component of the World Climate Research Program. Although total carbon dioxide (TCO2) is not an official WOCE measurement, a coordinated effort, supported in the United States by the U.S. Department of Energy (DOE) and the National Oceanic and Atmospheric Administration, is being made on WOCE cruises to measure the global, spatial, and temporal distributions of TCO2 and other carbon-related parameters. The CO2 survey goals include estimation of the meridional transport of inorganic carbon in a manner analogous to the oceanic heat transport (Bryden and Hall 1980; Brewer et al. 1989; Roemmich and Wunsch 1985), evaluation of the exchange of CO2 between the atmosphere and the ocean, and preparation of a database suitable for both carbon-cycle modeling and the subsequent assessment of the anthropogenic CO2 increase in the oceans. The final data set is expected to cover ~23,000 stations in the Atlantic, Pacific, and Indian oceans. The Research Vessel (R/V) Meteor Cruise 18/1, from Reykjavik, Iceland, to Hamburg, Germany, from September 2 to 25, 1991, completed WOCE Zonal Section A1E. It was one of a series of cruises starting in 1991 that are contributing to the WOCE North Atlantic Overturning Rate Determination (WOCE-NORD) program. The WOCE-NORD program is coordinated jointly by the Bundesamt fur Seeschiffahrt und Hydrographie (Hamburg) and the Institut fur Meereskunde (Hamburg). The sampling strategy of WOCE-NORD is to combine seasonally repeated hydrographic sections between southern Greenland and Iceland with current measurements from moored arrays. Program objectives include the direct determination of the overturning rates and the intensity of the meridional transports of mass, heat, and salt. Section A1E was chosen to be south of the major wintertime convection regions so as to avoid both water mass formation processes and shallow topography, either of which could cause difficulties in calculating volume transports. This document describes the cooperative efforts of chemical oceanographers from Brookhaven National Laboratory (BNL) and the Institut fur Meereskunde Kiel (IFMK) to make high-quality CO2 measurements along the WOCE Section A1E. 2. DESCRIPTION OF THE RESEARCH VESSEL AND EXPEDITION 2.1 R/V Meteor: Technical Details and History The R/V Meteor is owned by the Federal Republic of Germany's Ministry of Research and Technology (BMFT), which financed its construction. It is operated by the German Research Foundation (DFG), which provides about 70% of its operating funds while BMFT supplies the remainder. DFG also plans the scientific cruises and appoints the chief scientists. The Operations Control Office of the University of Hamburg is responsible for management, logistics, execution, and supervision of ship operations. These functions are performed through cooperation with expedition coordinators and the managing owners, the Reedereigemeinschaft Forschungsschiffahrt GmbH, located in Bremen, Germany. The latter is responsible for hiring, provisioning, and coordinating ship maintenance. Used for ocean research primarily in the Atlantic and Indian Oceans, the R/V Meteor routinely carries scientists from many different countries. Construction of the Meteor was completed in 1986 in Travemunde, Germany. The basic features of the vessel are as follows: Port of registration Hamburg Call sign DBBH Classification GL+100A4E2+MC Auto Operator Institut fur Meereskunde, Universit t Hamburg Built 1985-1986 at Schlichting Werft, Travemunde, West Germany Basic dimensions: Gross registered tonnage 3990 Net registered tonnage 1284 Displacement 4780 t Overall length 97.50 m Beam 16.50 m Draught max. 5.60 m Service speed 12 kn Depth main deck 7.70 m Personnel Crew: 32; scientists: 30 Main engine 4 x Mak6M 322 = 4 x 1000 kW at 750 rpm Propulsion Diesel-electrical, tandem-motor = 2 x 1150 kW Fuel consumption ~12.0 t IFO-80 per day at service speed Maximum cruise duration 60 days Nautical equipment Integrated navigation system with data transfer to position computer, echosounder synchronization and supervision, and data-processing facility Science quarters 20 laboratories on the main deck with ~400 m2 of working space for multidisciplinary research R/V Meteor (I) was constructed in 1925, the first research and survey vessel of that name. Owned by the German navy, it was based in Wilhelmshaven. One of its first expeditions was the German Atlantic Ocean Expedition of 1925-27, which was organized by the Institute of Marine Research in Berlin. Thereafter, the vessel was used for German physical, chemical, and microbiological marine investigations and for German navy surveying and fisheries protection duties. R/V Meteor (II) was planned after the 1950s; it was operated by the Deutsche Forschungsgemeinschaft (German Science Community) in Bad Godesberg and by the Deutsches Hydrographisches Institut (German Hydrographic Institute) in Hamburg. Commissioned in 1964, R/V Meteor (II) participated in the International Indian Ocean Expedition. Multipurpose R/V Meteor (III), used on the cruise described in this documentation, was completed in 1986 and replaced R/V Meteor (II). Based in Hamburg, it is used for German ocean research worldwide and for cooperative efforts with other nations researching in this field. The vessel serves scientists of all marine disciplines in all of the world's oceans. 2.2 Cruise Information Information about the R/V Meteor 18/1 cruise is summarized as follows: Ship name Meteor Cruise/leg 18/1 Ports of call Reykjavik, Iceland to Hamburg, Germany Dates September 2 25, 1991 Funding support German Science Community; Federal Ministry of Research and Technology, Bonn, Germany; and U.S. Department of Energy (DOE) Chief Scientist Professor Dr. Jens Meincke, Institut fur Meereskunde, Universit t Hamburg, Germany Master Heinrich Bruns Parameters measured Institution Principal investigators CTD, Salinity, XBT BSH A. Sy Nutrients SIO J. Swift, D. Bos, D. Muus Oxygen SIO J. Swift, D. Bos, D. Muus CFCs UBP W. Roether, A. Putzka Tritium, He, 14C IUPH R. Bayer TCO2 BNL, IFMK K. Johnson, B. Schneider, A. Morak, R. Ramirez Underway pCO2 IFMK B. Schneider Total alkalinity (TALK) IFMK L. Mintrop, A. Korves ADCP IFMH M. Bersch, J. Meincke Rain gauges IFMK H.-J. Isemer Participating Institutions BNL Brookhaven National Laboratory, U.S.A. BSH Bundesamt fur Seeschiffahrt und Hydrographie, Germany IFMH Institut fur Meereskunde, Universit t Hamburg, Germany IFMK Institut fur Meereskunde, Universit t Kiel, Germany IUPH Institut fur Umweltphysik, Universit t Heidelberg, Germany SIO Scripps Institution of Oceanography, U.S.A. UBP Universitat Bremen, Fachbereich Physik, Germany 2.3 Cruise Summary The BNL CO2 group, consisting of K. M. Johnson and R. Ramirez, arrived in Reykjavik, Iceland, on August 29 and went aboard the next day to join the IFMH CO2 group members, Drs. Bernd Schneider and Lutger Mintrop. Dr. Jens Meincke was already aboard as Chief Scientist. Setting up of the equipment began on August 30 and was completed on the morning of September 2. The R/V Meteor departed Reykjavik at 11 a.m. on September 2, 1991. The ship immediately encountered rough weather conditions with gale force winds. Two test stations were completed during the transit across the Denmark Strait to the first station (no. 558) on the South-East Greenland shelf, which was reached on September 5. The earlier gale force winds were replaced by a quiet period characterized by humid air masses over cold water, which resulted in fog. The hydrocast routine was interrupted by winch and rosette bottle-release problems on September 6 and 7 and by currentmeter deployments on September 9, 10 ,11, 14, and 19. Bad weather forced several delays on September 13, when the pressure dropped to 980 hPa, wind gusted to 11 Beaufort, and waves rose to 8 m. This scenario was repeated on September 17, and the slowly receding sea conditions thereafter continued to plague the oceanographic work until the end of the hydrographic program of WOCE section A1E at station 622 on September 21. Each rough period was followed by reduced sampling on stations (12 bottles instead of 24 on each rosette), but these stations were restricted to short lines perpendicular to the WOCE line. The station locations are shown in Fig. 1 (printed documentation). Of the six stations (592, 593, 595, 606, 607, and 608) taken normal to the WOCE line, only station 607 was sampled for carbonate system parameters. XBT measurements were made at selected CTD stations in parallel with the CTD casts, and acoustic Doppler current profiles (ADCP) were made continuously from September 2 to September 22 to measure the instantaneous near-surface currents. Two single-operator multiparameter metabolic analyzers (SOMMAs) from BNL (hereafter the systems are designated BNL I and BNL II), one potentiometric alkalinity titrator from IFMK and one ifrared-based system for underway pCO2 measurements from IFMK, were on board for this cruise. A total of 583 TCO2 samples, normally in conjunction with tracer samples, were taken from 31 section stations, 1 test station (no. 557) and two calibration stations (nos. 581, 608) from a total of 59 bottle casts. Not all 59 stations could be sampled for tracers and TCO2 because of the limited time available for analysis. The standard WOCE parameters (oxygen, nutrients, and salinity) were sampled on all stations, and on approximately every other station these were augmented by the tracer samples for CFCs, carbonate, helium, tritium, and radiocarbon as the ship steamed eastward from the southeastern tip of Greenland to the coast of Ireland. The density of the CO2 sampling was fairly constant, ~2 stations per day; the underway pCO2 system operated continuously. Both electrical and mechanical problems were noted for each of the SOMMA coulometer systems. BNL II was most severely affected and was declared nonoperational on September 16, when the magnetic valves on the SOMMA chassis could no longer be operated reliably, the electronic calibration factor suddenly changed by +0.11% (a factor of 10 higher than the usual precision of +/-0.01%), and the communication between the keyboard and PC became erratic. The final Certified Reference Material (CRM) run on this date was 6 umol/kg lower than the certified value, and test sample duplication was equally poor. When this system was operated several months later in the laboratory, all components functioned satisfactorily, and it was impossible to determine the cause of the shipboard difficulties. BNL I experienced two serious problems. First, the BNL I coulometer was lost when the photodetector amplifier failed on September 7. Fortunately, a backup coulometer from Kiel was available, and it was immediately placed in service. Second, the gas calibration system apparently failed on September 10 as a result of cross-talk between the gas sample loops (CO2 leaking from one loop into the other through a surface scratch or scoring of the valve, which contaminated the carrier gas). This manifested itself as a very noisy system with a very high and unusable blank. The problem was corrected by disconnecting the gas sample valve from the system so that the carrier gas (N2) passed directly from the gas cylinder into the SOMMA stripper. Because of the rough weather, plans for a return voyage around the north of Scotland to Hamburg were changed, and the ship arrived in Hamburg on September 25, via the English Channel, where winds astern arising from a low pressure system near the Faeroe Islands hastened the return voyage. 3. DESCRIPTION OF VARIABLES AND METHODS The data file met18.dat (see descriptions of data files in Part 2) in this numeric data package (NDP) contains the following variables: station numbers; cast numbers; sample numbers; bottle numbers; CTD pressures, temperatures, and salinities; reversing thermometers readings; potential temperatures; bottle salinities; concentrations of dissolved oxygen, silicate, nitrate, nitrite, and phosphate; TCO2 and TALK concentrations; and quality flags. The station inventory file m18sta.inv contains expocodes, section numbers, station numbers, cast numbers, sampling dates (i.e., month, day, year), sampling times, latitude, longitude, and bottom depth for each station. The data file uwpco2.dat contains sampling dates (i.e., day, month, year), sampling times, latitude, longitude, sea surface salinity, sea surface temperature, and underway pCO2 measurements. Water samples were collected in 24 General Oceanics 10-L Niskin bottles mounted on a Neil Brown Mark III CTD instrument (S/N NB3) provided by IFMK. Data were acquired at a rate of 32 ms/cycle by using Oceansoft Rev. 3.1. Further details are given by Meincke (1993), and additional data concerning postcruise and precruise laboratory calibrations of the CTD temperature, pressure, conductivity, and oxygen sensors may be found in Siedler and Zenk (1992) and Ruhsam (1994). ADCP measurements to a depth of 300 m were made nearly continuously (with some breaks for rough weather and minor computer malfunctions) from September 2 to 22 with a hull-mounted system from RD Instruments (San Diego) that used a pulse frequency of 150 kHz. The rosette systems used with the CTD on this cruise experienced various mechanical and electrical problems such that tripping failures were not uncommon especially at stations 596-613. Repeated checks on board and several careful verifications with the complete bottle data sets were carried out, and the current pressures for each sample are considered correct by the responsible personnel. Reversing thermometers, both electronic (SIS, Kiel) and mechanical (Gohla Precision, Kiel), were also read at the completion of each cast. The processing and quality control of CTD and bottle data performed at BSH followed the guidelines published in the WOCE Operations Manual (WHPO 91-1, 1991). Salinity corrections were made by using bottle salinities measured 1-2 days after collection and determined on a Guildline Autosal model 8400A, which was standardized at each station with reference water (batch P112). Because of temporal conductivity sensor shifts, separate corrections were applied for stations 558-566, 567-602, and 603-622. The final salinity data are expected to be accurate to +/-0.002 on the Practical Salinity Scale (PSS). Bottle oxygen was determined by Winkler titration following the techniques of Carpenter (1965) and Culberson and Will (1991), by using standards and blanks run in seawater. Subsequently, all Winkler results were recalculated and verified by staff of Oceanographic Data Facility at SIO. The concentrations of nitrate, nitrite, phosphate, and silicate dissolved in seawater were determined for samples collected in high-density polyethylene screw-capped bottles by using a Technicon Autoanalyzer according to procedures given in Hager et al. (1972) and Atlas et al. (1971) and by using the spectrophotometric methods of Armstrong et al. (1967) and Bernhardt and Wilhelms (1967). The analyses were completed within 24 h of sampling, including storage at 6 C for no more than 15 h. Preweighed standards were used to prepare the working standards on board ship. The TCO2 concentration was determined by using two SOMMAs described and designed by K. M. Johnson and coworkers (Johnson et al. 1985, 1987; Johnson and Wallace 1992). Along with 158 duplicates, 583 individual samples (total analyzed = 741) from 33 stations (Fig. 2 in printed documentation) were collected in 300-mL, precombusted (450 C for 24 h) BOD bottles and immediately poisoned with HgCl2, according to DOE's Handbook of Methods for the Analysis of the Various Parameters of the Carbon Dioxide System in Sea Water (DOE 1994). Before analysis the BOD bottles were kept in darkness in a cold room until thermally equilibrated to the analytical temperature. Dr. Andrew Dickson of SIO supplied 61 CRMs (DOE 1994), which were also analyzed (37 on BNL I and 24 on BNL II). The CRMs were from Batch 7 (B7), which was a filtered sterile salt solution (S = 37.12) spiked with Na2CO3, and analyzed for TCO2 by vacuum extraction and manometry in the laboratory of C. D. Keeling at SIO. The certified TCO2 value was 1926.41 +/-0.82 umol/kg (n = 13). Seawater introduced from an automated "to deliver" pipette into a stripping chamber was acidified, and the resultant CO2, after drying, was coulometrically titrated on a model 5011 UIC coulometer. In the coulometer cell, the hydroxyethylcarbamic acid that formed from the reaction of CO2 and ethanolamine was titrated coulometrically (electrolytic generation of OH-) with photometric end point detection. The product of the time and the current passed through the cell during the titration was 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 SOMMA- coulometer system was calibrated with pure CO2 through the use of hardware consisting of an eight-port gas sampling Valve (GSV) with two sample loops connected to a source of pure CO2 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 ambient (T) and (P). The molar volume of CO2 [V(CO2)] was calculated iteratively from an expression using the instantaneous barometric pressure (P), loop temperature (T), gas constant (R), and the first virial coefficient B(T) for pure CO2: V(CO2) = RT / P[1 + B(T) / V(CO2)] . (1) The ratio of the calculated mass to the mass determined coulometrically was the gas calibration factor (CALFAC) used to correct the subsequent titrations for small departures from 100% theoretical response (DOE 1994). The volume of the loops was determined gravimetrically with deionized water by the method of Wilke et al. (1993). The standard operating procedure was to make gas calibrations daily or for each new titration cell used (normally one cell per day). Before the cruise, the to deliver volume (TDV) of the SOMMA sample pipette was determined (calibrated) gravimetrically at 20 C with milli-Q deionized water, which had been degassed with Helium. The thermostatted sample pipette was filled with water at the same temperature, and then discharged into preweighed 50-mL serum bottles which were reweighed on a model R300S (Sartorius, G ttingen, Germany) balance. The apparent weight (g) of water collected (Wair) was corrected to the mass in vacuo (Mvac) from the following equation: Mvac = Wair + Wair(0.0012/d - 0.0012/8.0) , (2) 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. TDV was calculated by using the following equation: TDV = Mvac/d . (3) This procedure was repeated at sea, except the serum bottles were crimp-sealed and reweighed on shore within 3 weeks of collection. The precruise TDV of the pipette for system BNL I was 28.7108 mL at 20 C. During the cruise the pipette temperature was kept at ~10.2 C +/- 0.3 C. The calculated TDV at 10.2 C (TDVT2) was 28.7080 mL: TDV(T2) = TDV(T1) [1 + a(v) (T2 - T1)] , (4) where a(v) is the coefficient of volumetric expansion for pyrex-type glass (1 x 10(-5) C(-1)), T2 is the measurement temperature, and T1 is the calibration temperature. The corresponding results for the BNL II pipette were 29.6954 and 29.6925 mL, respectively. During the cruise, eight TDV samples were collected at 10.2 C from the BNL I pipette and sealed for reweighing. The TDV from these weighings was 28.6845 +/- 0.0058 mL (0.02%), which differed from the calculated TDV of 28.7080 mL by -0.0235 mL, or -0.082%. For the BNL II pipette, 11 samples were taken at 10.2 C which gave a TDV of the 29.6712 +/- 0.0065 mL (0.02%), which differed from the calculated TDV of 29.6925 mL by -0.0213 mL, or -0.072%. Because the original laboratory calibration took place at 20 C, and all of the analytical work aboard ship was done at 10.2 C +/- 0.3 C we have used the latter (shipboard) results for TDV to calculate the TCO2 values (i.e., for BNL I, TDV = 28.6845 mL at 10.2 C; for BNL II, TDV = 29.6712 mL at 10.2 C). These data confirmed the current practice of ensuring identical calibration and analytical temperatures because it appeared that just correcting for glass expansion was not adequate to describe the TDV at temperatures significantly different from the calibration temperature (see also DOE 1994). An IBM-compatible personal computer with two RS232 serial ports, one 24-line digital input/output port, and one analog-to-digital port was used to control the coulometer, barometer, solid state control relays, and temperature sensors, respectively. The temperature sensors (model LM34CH, National Semiconductor, Santa Clara, California), with a voltage output of 10 mV/ F built into the SOMMA, were calibrated against thermistors certified to 0.01 C (PN CSP60BT103M, Thermometrics, Edison, New Jersey) by using a certified mercury thermometer as a secondary standard. These sensors monitored the pipette, gas sample loop, and the coulometer cell temperatures. The barometer, model 216B-101 Digiquartz Transducer (Paroscientific, Inc., Redmond, Washington), was factory-calibrated for pressures between 11.5 and 16.0 psia. The SOMMA software was written in GWBASIC Version 3.20 (Microsoft Corp., Redmond, Washington), and the instrument was driven from the computer. The analytical method for determination of TCO2 concentration in seawater used during R/V Meteor Cruise 18/1 differed from the technique described in an earlier data report (Johnson et al. 1995) for R/V Meteor Cruise 15/3 (March 1991), during which an electronic calibration procedure was used to check the theoretical response of the coulometers's voltage to frequency converter (VFC) as described in Johnson et al. (1993) and DOE (1994). 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, electronic calibration yielded a straight line passing through the origin (intercept = 0) with a slope of 1. Calibrations and titrations were done with the coulometer in the counts mode (the total charge passed during a titration was displayed as the number of counts accumulated by the VFC). From the factory calibration of the VFC and the value of the Faraday (96489 Coulomb/mol), a scaling factor of 4.82445 103 counts/ mol was derived, and the theoretical number micromoles of carbon titrated (M) was determined by the following equation: M = [counts/4824.45 - (Blank x T(T) ) - (ECint x I(T))]/ECslope ,(5) where T(T) is the length of the titration in minutes, Blank is the system blank in umol/min, ECint is the intercept from electronic calibration in mol/min, IT the time of continuous current flow in minutes, and ECslope is the slope from electronic calibration. Note that the slope obtained from the electronic calibration procedure applied for the entire length of the titration, but the intercept applied only for the period of continuous current flow (usually 3-4 min). The TCO2 concentration in umol/kg was calculated with the following equation: C(T) = [M x (CALFAC) x (1000/TDV(T) x p)] x 1.00017 , (6) where CT is the TCO2, CALFAC is the gas calibration factor, TDV(T) is the "to deliver" volume of the pipette in mL at the analytical temperature, p is the density of seawater in kg/L from the equation of state (Millero and Poisson 1981), and 1.00017 corrects for the dilution of the sample by the 100 uL of HgCl2 solution added to the sample bottle. As a consequence of the coulometer and gas calibration problems described in Sect. 2.3, BNL I was operated between September 13 and September 23 without a functioning gas calibration system. For TCO2 calculations starting on September 13, the mean CALFAC of 1.002844 (n = 7) obtained for the period September 4-10 was used. No samples were run on BNL I on September 11 and 12. BNL II was continuously operated between September 4 and 15, and calculations were made with the daily gas calibration factors for that instrument. No samples were run on BNL II after September 15. The results of the CRM analyses are shown in Table 1. Table 1. Summary of CRM TCO2 analyses made aboard the R/V Meteor during Cruise 18/1 (September 1991) with two SOMMA-Coulometer Systems (BNL I and BNL II). The CRMs were from Batch 7 and had a salinity of 37.12 and a certified TCO2 of 1926.41 +/- 0.82 umol/kg (n = 13). ____________________________________________________________________________________ System No. Mean SD R. S. D. Difference Period (n) ------(umol/kg)----- (%) found-certified (1991) ____________________________________________________________________________________ BNL I(a) 14 1926.19 0.89 0.05 -0.22 4-10 September BNL I(b) 23 1925.66 1.46 0.08 -0.75 13-23 September BNL II 24 1926.90 1.65 0.09 +0.49 4-15 September Combined 61 1926.27 1.52 0.08 -0.14 4-23 September ____________________________________________________________________________________ (a) Period with functioning gas calibration unit (September 4 10). (b) Period without a functioning gas calibration unit (September 13 22). This was the first cruise during which two SOMMA systems were used side-by-side to analyze samples from the same profile and measurements of system precision and bias were made in addition to the CRM analyses. The system precision data are given in Table 2. For these data, "within-sample" precision was the average difference between two replicates analyzed from the same sample bottle, "between-sample" precision was the average difference between duplicate sample bottles taken from the same Niskin bottle, "between-Niskin" precision was the average difference between single sample bottles taken from two Niskin bottles closed at the same depth, and Sp2 was the pooled standard deviation calculated from multiple "between-sample" replicates (n > 2; stations 557, 581, and 608) of the same sample analyzed on the same instrument (instrument specific) or from replicates of the same sample analyzed on each instrument (method specific). The Sp2 was the square root of the pooled variance, according to Youden (1951): (see in printed documentation) (7) Table 2. Summary of sample precision for TCO2 analyses made aboard the R/V Meteor during Cruise 18/1 September 4 15, 1991 with two SOMMA-Coulometer Systems (BNL I and BNL II). The mean precision data are given as the mean of the absolute values of the mean differences between two duplicates analyzed on the same instrument from n samples. See text for explanation of Sp2. _______________________________________________________________________________________ System Mean bottle precision (+/-umol/kg) Sp2 Within-sample (n) Between-sample (n) Between-Niskin (n) (k,n) _______________________________________________________________________________________ BNL I 0.77 (18) 0.73 (31) 0.39 (12) 1.49 (3,26) BNL II 1.10 (19) 0.83 (3) 0.65 (3) 1.68 (2,26) Cruise totals 0.93 (37) 0.79 (34) 0.52 (15) 1.65 (34,93) ________________________________________________________________________________________ For the instrument specific Sp2, k is the number of samples where more than two replicates were analyzed on the same instrument, and n is the total number of replicates analyzed from k samples. The method specific Sp2 was calculated from 34 samples (k) for which at least one replicate was analyzed on each instrument [93 replicates (n) analyzed between the two instruments]. If more than one replicate was analyzed on the same instrument, the mean was used to calculate Sp2 according to the equation from Youden (1951), (Eq. 7). Thus n(j) = k x 2 (68 instead of 93). This treatment reduces the degrees of freedom (n(j) - k) to 34 from 59 (93 - k) and yield the most conservative estimate of precision for a single measurement, irrespective of the instrument it was made on. Overall sample precision (method specific Sp2) was +/-1.65 umol/kg which agreed very well with the precision of the CRM analyses on both instruments (+/-1.52 umol/kg, n = 61, Table 1). Note that BNL I, as a rule, gave slightly better precision than BNL II and that the other precision estimates were consistently better than Sp2. However, the higher value of +/-1.65 umol/kg was considered to be the most conservative estimate of analytical precision because it included all sources of error random and systematic encountered over several days. System bias was also checked by comparing the calibration station (no. 581) samples from a depth of ~2033 m on both instruments over several days. For BNL I, the mean result was 2159.07 +/-0.61 umol/kg (n = 5, analyzed between September 12 and 16), and the corresponding result for BNL II was 2158.26 +/-1.18 umol/kg (n = 12, analyzed between September 11 and 13). The absolute value of the difference was 0.81 umol/kg with BNL I giving a slightly higher result. The mean difference and the absolute value of the mean difference between duplicate analyses for the 34 samples in Table 2 were calculated and are summarized in Table 3. Table 3. Summary of TCO2 analyses for duplicate samples, for which one of the duplicates was analyzed on SOMMA-Coulometer System BNL I and the other was analyzed on BNL II aboard the R/V Meteor during Cruise 18/1 __ _______________________________________________________________________________ Comparison BNL I (n) BNL II (n) Difference (I - II) Abs (I II) __________________________________________________________________________________ CRM 1926.32 (19) 1926.90 (24) -0.58 0.58 Station 581 2159.07 (5) 2158.26 (12) +0.81 0.81 Samples, other 2126.73 (34) 2128.38 (34) -1.65 1.87 --------- ------ Mean -0.47 1.09 __________________________________________________________________________________ Table 3 shows that BNL I gave slightly lower results in comparison with BNL II for the CRM and most samples but that this trend was reversed for the test station (581) samples. The difference between the overall mean difference (-0.47 umol/kg) and the mean absolute value of the absolute differences (1.09 umol/kg) suggests that it would be difficult to assign a uniform instrument bias for the duration of the cruise, and accordingly, no correction of any kind for instrumental bias has been applied to the data. In effect, it has been decided to accept a conservative estimate of precision that includes an estimate of bias (+/-1.65 umol/kg, Table 2) for any single measurement instead of applying a bias correction to the data from either instrument. In aggregate, Tables 1 3 indicate that a single TCO2 measurement is accurate and precise to +/-1.6 umol/kg. As a final estimate of data quality, duplicate samples from seven Niskin bottles at five stations were collected for later shore-based reference analyses of TCO2 by vacuum extraction/manometry performed in the laboratory of Dr. Charles Keeling at SIO. The results are given in Table 4, in which the BNL data are compared with the SIO results (Guenther et al. 1994). All samples except the shallow sample from station 580 are clearly consistent with our estimate of accuracy and precision, given previously. Temperature sensors were not included in the CRM shipping crates (as is now standard operating procedure), so the temperature history of these samples between cold storage aboard ship and their arrival at SIO was not known. Table 4 supersedes Tables 3e and 5e from Guenther et al. (1994). Table 4. Comparison of shipboard analyses of TCO2 by coulometry (BNL) during the R/V Meteor Cruise 18/1 and the shore-based reference analyses of TCO2 by manometry on duplicate samples in the laboratory of C. D. Keeling at SIO. The reference analyses were made February March 1994. ______________________________________________________________________________ Station Sample Niskin Depth TCO2 (BNL) TCO2 (SIO) Differ. Salinity no. date no. (m) (umol/kg) (umol/kg) BNL-SIO differ(a) _______________________________________________________________________________ 575 09.09.91 24 10 2088.25 2087.98 + 0.27 + 0.002 575 09.09.91 13 1095 2152.24 2154.55 - 2.31 - 0.019 580 10.09.91 23 27 2085.75 2094.58 - 8.83 - 0.003 580 10.09.91 1 2367 2157.52 2160.00 - 2.48 - 0.003 581(b) 10.09.91 2 2033 2158.48 2158.73 - 0.25 - 0.004 596 14.09.91 14 690 2167.83 2167.74 + 0.09 - 0.005 603 16.09.91 1 4063 2202.42 2203.84 - 1.42 - 0.001 -------- -------- Mean differences - 2.13 - 0.005 _______________________________________________________________________________ (a) The difference between the ship s CTD sample salinity and the salinity measured at SIO. (b) Calibration station. The BNL result is the mean of 17 analyses on the two systems between September 11 and 16. Note that six of the seven differences were within the analytical precision of the methods, and salinities agreed to within 0.005, with evaporative losses ruled out. Total Alkalinity samples were collected in 500-mL bottles with the same precautions as for TCO2. Samples were stored in the dark at 4 C and analyzed within 24 h. Samples were transferred into a closed titration cell with a volume of ~120 mL and titrated at 25 C +/- 0.1 C with 0.1 M HCl containing 0.6 M NaCl. The titration cell was based on the systems described by Bradshaw and Brewer (1988) and Millero et al. (1993). The potential was followed with an electrode pair consisting of a ROSS (Orion Inc.) glass pH electrode and a ROSS AgCl reference electrode connected to a high-precision digital voltmeter. The titration was controlled by a computer, which waited for stable emf-readings before adding the next acid increment. The titration curve was analyzed with a modified GRAN-plot method described by Stoll et al. (1993), using the carbonic acid constants of Goyet and Poisson (1989), and taking into account the silicate and phosphate concentrations of the sample to obtain the titration alkalinity. The precision of the method was +/-2.0 umol/kg, which was determined by replicate analysis of samples. Standardization was accomplished with NaCO3 standards in NaCl solutions corrected for the blank arising from impurities in the salt. Underway pCO2 was measured by using the method of Schneider et al. (1992). Surface seawater was continuously pumped along the cruise track (Fig. 3 in the printed documentation) at a rate of 200 300 mL/min into a glass equilibrator with a volume of ~300 mL. The seawater was equilibrated with continuously circulating air entering the bottom of the equilibrator through a frit from a closed-loop system. This system included a heat exchanger to keep the air at sample temperature, a filter and water trap, and an infrared (IR) analyzer (Siemens, Ultrmat 5F) for the determination of the CO2 content of the equilibrated air. The infrared analyzer and equilibrator temperature sensor were connected to a computer or to an analog recorder for data display and preservation. The time constan for the equilibration was ~3 min, which corresponded to a spatial resolution of 0.5 mile with the ship steaming at 10 knots. Atmospheric air was periodically measured, and the system was calibrated every 12 h through the use of calibration gases with CO2 mixing ratios of 252.5 and 412.8 ppm (v). Pressure corrections were made for the effect of water vapor on total pressure in the equilibrator and the pressure at the inlet of the IR analyzer; the correction for the difference between in situ temperature and measuring temperature was made according to Gordon and Jones (1973). Figure 4 (in the printed documentation) presents the plots of the underway sea surface salinity, temperature, and pCO2 measured during R/V Meteor Cruise 18/1. 4. DATA CHECKS AND PROCESSING PERFORMED BY CDIAC An important part of the NDP process at the Carbon Dioxide Information Analysis Center (CDIAC) involves the quality assurance (QA) of data before distribution. Data received at CDIAC are rarely in a condition that would permit immediate distribution, regardless of the source. To guarantee data of the highest possible quality, CDIAC conducts extensive QA reviews that involve examining the data for completeness, reasonableness, and accuracy. Although they have common objectives, these reviews are tailored to each data set, often requiring extensive programming efforts. In short, the QA process is a critical component in the value-added concept of supplying accurate, usable data. The following summarizes the data processing and QA checks performed by CDIAC on the data obtained during the R/V Meteor Cruise 18/1 in the North Atlantic Ocean. 1. Carbon-related data and preliminary hydrographic measurements were provided to CDIAC by K. M. Johnson and D. W. R. Wallace of BNL. The final hydrographic and chemical measurements and the station information files were provided by the WOCE Hydrographic Program Office after quality evaluation. A FORTRAN 77 retrieval code was written and used to merge and reformat all data files. 2. To check for obvious outliers, all data were plotted using a PLOTNEST.C program written by Stewart C. Sutherland of 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. 5 and 6 in the printed documentation). 3. To identify noisy data and possible systematic, methodological errors, property-property plots for all parameters were generated (Fig. 7 in the printed documentation) and carefully examined. 4. All variables were checked for values that exceeded physical limits, such as sampling depth values exceeding the given bottom depths. 5. Dates, times, and coordinates were checked for bogus values (i.e., values of MONTH that were <1 or >12; DAY values <1 or >31; YEAR values < or > 1991; TIME values <0000 or >2400; LAT values <49.000 or >65.000; LONG values < 43.000 or >-3.000). 6. Station locations (latitudes and longitudes) and sampling times were examined for consistency with maps and with cruise information supplied by K. M. Johnson and D. W. R. Wallace, BNL. 7. The designation for missing values, given as 9.0 in the original files, was changed to 999.9. 5. HOW TO OBTAIN THE DATA AND DOCUMENTATION This database is available on request in machine-readable form, without charge, from CDIAC. CDIAC will also distribute subsets of the database as needed. It can be acquired on 9-track magnetic tape; 8-mm tape; 150-mB, 1/4-in. tape cartridge; IBM-formatted floppy diskettes; or from CDIAC's anonymous File Transfer Protocol (FTP) area through the Internet (see FTP address below). Requests should include any specific media instructions required by the user to access the data (i.e., 1600- or 6250-BPI, labeled or nonlabeled tapes, ASCII or EBCDIC characters, variable- or fixed-length records; 3.5- or 5.25-in. floppy diskettes, high or low density; 8200 or 8500 format, 8-mm tape). Magnetic tape requests not accompanied by specific instructions will be filled on 9-track, 6250-BPI, standard-labeled tapes with EBCDIC characters. Requests should be send to the following address: Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Post Office Box 2008 Oak Ridge, Tennessee 37831-6335 U.S.A. Telephone: (423) 574-0390 or (423) 574-3645 Fax: (423) 574-2232 Electronic Mail: cdiac@ornl.gov The data files can also be acquired from CDIAC's anonymous FTP area through the Internet by following these steps: FTP to cdiac.esd.ornl.gov (128.219.24.36), Enter ftp or anonymous as the user ID, Enter your electronic mail address as the password (e.g., alex@alex.esd.ornl.gov ), Change to the directory /pub/ndp056 , and Acquire the files by using the FTP get or mget command. The data files can also be acquired through CDIAC's World Wide Web site at the following address: http://cdiac.esd.ornl.gov/oceans/home.html 6. REFERENCES Armstrong, F. A. J., C. R. Stearns, and J. D. H. Strickland. 1967. The measurement of upwelling and subsequent biological processes by means of the Technicon Autoanalyzer and associated equipment. Deep-Sea Res. 14:381-89. Atlas, E. L., S. W. Hager, L. L. Gordon, and P. K. Park. 1971. A Practical Manual for Use of the Technicon Autoanalyzer in Seawater Nutrient Analyses, Revised. Technical Report 215, Reference 71-22. Oregon State University, Department of Oceanography. Bernhardt, H., and A. Wilhelms. 1967. The continuous determination of low level iron, soluble phosphate and total phosphate with the AutoAnalyzer (R). Technicon Symposia, Vol. I, 385-89. Bradshaw, A. L., and P. G. Brewer. 1988. High precision measurements of alkalinity and total carbon dioxide in seawater by potentiometric titration-1. Presence of unknown protolyte(s). Mar. Chem., 23:69-86. 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. Carpenter, J. H. 1965. The Chesaspeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol. Oceanogr. 10:141-43. Culberson, C. H., and R. T. Will. 1991. A comparison of methods for the determination of dissolved oxygen in seawater. WHP Office Report, WHPO 91-2. DOE (U.S. Department of Energy). 1994. Handbook of methods for the analysis of the various parameters of the carbon dioxide system in sea water. Ver. 2. ORNL/CDIAC-74. A. G. Dickson and C. Goyet (eds.). Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn. Gordon, L. I., and L. B. Jones. 1973. The effect of temperature on carbon dioxide partial pressure in seawater. Mar. Chem. 1:317-22. Goyet, C., and A. Poisson. 1989. New determination of carbonic acid dissociation constants in seawater as a function of temperature and salinity. Deep-Sea Res. 36:1635-54. Guenther, P. R., C. D. Keeling, and G. Emanuele III. 1994. Oceanic CO2 Measurements for the WOCE Hydrographic Survey in the Pacific Ocean, 1990 1991: Shore Based Analyses. SIO Reference Series, Ref. No. 94-28. University of California, San Diego, Calif. Hager, S. W., E. L. Atlas, L. G. Gordon, A. W. Mantyla, and P. K. Park. 1972. A comparison at sea of manual and autoanalyzer analyses of phosphate, nitrate, and silicate. Limnol. Oceanogr. 17:931 37. 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, Oak Ridge, Tenn. Johnson, K. M., A. E. King, and J. M. Sieburth. 1985. Coulometric TCO2 analyses for marine studies: An introduction. Mar. Chem. 16:61-82. Johnson, K. M., J. M. Sieburth, P. J. B. Williams, and L. Br ndstr m. 1987. Coulometric TCO2 analysis for marine studies: Automation and calibration. Mar. Chem. 21:117-33. 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. Mar. Chem. 44:167-87. Johnson, K. M., D. W. R. Wallace, R. 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). Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, Oak Ridge, Tenn. Meincke, J. (ed.). 1993. WOCE-NORD 1991, Cruise No. 18, 2 September 26 - September 1991. METEOR-Berichte No. 93-1. Institut fur Meereskunde, Universitat Hamburg, Germany. Millero, F. J., and A. Poisson. 1981. International one-atmosphere equation of state for sea water. Deep-Sea Res. 28:625-29. Millero, F. J., J.-Z. Zhang, K. Lee, and D. M. Campbell. 1993. Titration alkalinity of seawater. Mar. Chem. 44:153-65. Roemmich, D., and C. Wunsch. 1985. Two transatlantic sections: Meridional circulation and heat flux in the subtropical North Atlantic Ocean. Deep-Sea Res. 32:619-64. Ruhsam, C. M. 1994. WHP One-Time Section A9 Data Report. WOCE Special Analysis Center, Bundesamt f r Seeschiffahrt and Hydrographie, Hamburg, Germany (unpublished manuscript). Schneider, B., K. Kremling, and J. C. Duinker. 1992. CO2 partial pressure in northeast Atlantic and adjacent shelf waters: Processes and seasonal variability. J. Mar. Systems 3:453-63. Siedler, G., and W. Zenk. 1992. WOCE Sudatlantik 1991, Reise Nr. 15, 30 Dezember 1990 23 Marz 1991. METEOR-Berichte 92-1. Universitat Hamburg, Germany. Stoll, M. H. C., J. W. Rommets, and H. J. W. De Baar. 1993. Effect of selected calculation routines and dissociation constants on the determination of total carbon dioxide in seawater. Deep-Sea Res. 40:1307-22. 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. Anal. Chem. 65:2403-06. WOCE Operations Manual. 1991. WHP Office Report 90-1. Rev.1. Unpublished Manuscript. WOCE Hydrographic Programme Office. Woods Hole Oceanographic Institution, Woods Hole, Mass. (unpublished manuscript). 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 seven files that compose this NDP (Table 5). Because CDIAC distributes the data set in several ways (e.g., by anonymous FTP, on floppy diskette, on 9-track magnetic tape), each of the five files is referenced by both a file number and an ASCII file name, which is given in lower-case, bold-faced type (e.g., ndp056.txt). The remainder of this section describes or lists the contents of each file. The files are discussed in the order presented in Table 5. Table 5. Content, size, and format of data files ___________________________________________________________________________ File number, name, Logical File size Block Record and description records in bytes size length ___________________________________________________________________________ 1. ndp056.txt: 1,411 83,319 8,000 80 A detailed description of the cruise network, the three FORTRAN 77 data retrieval routines, and the three oceanographic data files 2. stainv.for: 36 1,249 8,000 80 A FORTRAN 77 data retrieval routine to read and print met18sta.inv (File 5) 3. met18dat.for: 44 1,892 8,000 80 A FORTRAN 77 data retrieval routine to read and print met18.dat (File 6) 4. uwpco2.for: 36 1,218 8,000 80 A FORTRAN 77 data retrieval routine to read and print uwpco2.dat (File 7) 5. met18sta.inv: 76 5,598 4,100 41 A listing of the station locations, sampling dates, and sounding bottom depths for all stations 6. met18.dat: 1,224 192,149 16,000 160 Hydrographic, carbon dioxide, and nutrient data from all stations 7. uwpco2.dat: 2,122 132,833 16,000 120 Underway pCO2 data collected along the cruise track _____ _______ Total 4,964 426,254 _______________________________________________________________________________ ndp056.txt (File 1) This file contains a detailed description of the data set, the three FORTRAN 77 data retrieval routines, and the three oceanographic data files. It exists primarily for the benefit of individuals who acquire this database as machine-readable data files from CDIAC. stainv.for (File 2) This file contains a FORTRAN 77 data retrieval routine to read and print met18sta.inv (File 5). The following is a listing of this program. For additional information regarding variable definitions, variable lengths, variable types, units, and codes, please see the description for met18sta.inv. c**************************************************************** c* FORTRAN 77 data retrieval routine to read and print the * c* file named "met18sta.inv" (File 5) * c**************************************************************** INTEGER stat, cast, depth CHARACTER date*6, expo*8, sect*3, time*4 REAL latdcm, londcm OPEN (unit=1, file='met18sta.inv') OPEN (unit=2, file='m18stat.inv') write (2, 5) 5 format (2X,'R/V METEOR CRUISE 18 LEG 1',5X,'WOCE LINE A1E',/, 1 2X,'EXPOCODE',2X,'SECT',2X,'STNNBR',2X,'CASTNO',5X,'DATE', 2 3X,'TIME',5X,'LATDCM',5X,'LONDCM',3X,'DEPTH',/) read (1, 6) 6 format (/////////////) 7 CONTINUE read (1, 10, end=999) expo, sect, stat, cast, date, time, 1 latdcm, londcm, depth 10 format (2X, A8, 3X, A3, 5X, I3, 7X, I1, 3X, A6, 3X, A4, 5X, 1 F6.3, 4X, F7.3, 4X, I4) write (2, 20) expo, sect, stat, cast, date, time, latdcm, 1 londcm, depth 20 format (2X, A8, 3X, A3, 5X, I3, 7X, I1, 3X, A6, 3X, A4, 5X, 1 F6.3, 4X, F7.3, 4X, I4) GOTO 7 999 close(unit=1) close(unit=2) stop end met18dat.for (File 3) This file contains a FORTRAN 77 data retrieval routine to read and print met18.dat (File 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 met18.dat. c**************************************************************** c* FORTRAN 77 data retrieval routine to read and print the * c* file named "met18.dat" (File 6). * c**************************************************************** CHARACTER bot*3, qualt*10 INTEGER sta, cast, samp REAL pre, ctdtmp, theta, revtmp, ctdsal, salt, oxygen, silcat REAL nitrat, nitrit, phspht, tcarb, talk OPEN (unit=1, file='met18.dat') OPEN (unit=2, file='met18.data') write (2, 5) 5 format (2X,'STNNBR',2X,'CASTNO',2X,'SAMPNO',2X,'BTLNBR',2X, 1 'CTDPRS',4X,'CTDTMP',3X,'REVTMP',4X,'CTDSAL',5X,'THETA',4X 2 'SALNTY',2X,'OXYGEN',2X,'SILCAT',2X,'NITRAT',2X,'NITRIT',2X, 3 'PHSPHT',2X,'ALKALI',2X,'TCARBN',6X,'QUALT1',/,36X,'DBAR', 4 4X,'ITS-90',3X,'ITS-90',4X,'PSS-78',7X,'DEG',4X,'PSS-78',1X, 5 7('UMOL/KG',1X),10X,'*',/,25X,'*******',30X,'*******',13X, 6 8('*******',1X),10X,'*') read (1, 6) 6 format (/////////////) 7 CONTINUE read (1, 10, end=999) sta, cast, samp, bot, pre, ctdtmp, 1 revtmp, ctdsal, theta, salt, oxygen, silcat, nitrat, nitrit, 2 phspht, talk, tcarb, qualt 10 format (5X, I3, 7X, I1, 6X, I2, 5X, A3, 2X, F6.1, 1X, F9.4, 1 1X, F8.3, 1X, F9.4, 1X, F9.4, 1X, F9.4, 2X, F6.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, A10) write (2, 20) sta, cast, samp, bot, pre, ctdtmp, 1 revtmp, ctdsal, theta, salt, oxygen, silcat, nitrat, nitrit, 2 phspht, talk, tcarb, qualt 20 format (5X, I3, 7X, I1, 6X, I2, 5X, A3, 2X, F6.1, 1X, F9.4, 1 1X, F8.3, 2X, F9.4, 1X, F9.4, 1X, F9.4, 2X, F6.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, A10) GOTO 7 999 close(unit=1) close(unit=2) stop end uwpco2.for (File 4) This file contains a FORTRAN 77 data retrieval routine to read and print uwpco2.dat (File 7). 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 uwpco2.dat. c**************************************************************** c* FORTRAN 77 data retrieval routine to read and print the * c* file named "uwpco2.dat" (File 7) * c**************************************************************** INTEGER day, month, year CHARACTER time*5 REAL latdcm, londcm, salt, temp, pco2 OPEN (unit=1, file='uwpco2.dat') OPEN (unit=2, file='uwpco2.data') write (2, 5) 5 format (2X,'R/V METEOR CRUISE 18 LEG 1',5X,'WOCE LINE A1E',/, 1 4X,'DATE',6X,'TIME',3X,'LATDCM',4X,'LONDCM',3X,'SURFSAL', 2 1X,'SURFTMP',2X,'PCO2',/) read (1, 6) 6 format (/////////////) 7 CONTINUE read (1, 10, end=999) day, month, year, time, latdcm, 1 londcm, salt, temp, pco2 10 format (I2, 2X, I1, 2X, I4, 2X, A5, 3X, F6.3, 3X, F7.3, 3X, 1 F7.4, 2X, F5.2, 2X, F5.1) write (2, 20) day, month, year, time, latdcm, 1 londcm, salt, temp, pco2 20 format (I2, 2X, I1, 2X, I4, 2X, A5, 3X, F6.3, 3X, F7.3, 3X, 1 F7.4, 2X, F5.2, 2X, F5.1) GOTO 7 999 close(unit=1) close(unit=2) stop end met18sta.inv (File 5) This file provides station inventory information for each of the 61 stations occupied during the R/V Meteor Cruise 18/1. Each line of the file contains an expocode, section number, station number, cast number, sampling date, sampling time, latitude, longitude, and sounding depth. The file is sorted by station number and can be read by using the following FORTRAN 77 code (contained in stainv.for, File 2): INTEGER stat, cast, depth CHARACTER date*6, expo*8, sect*3, time*4 REAL latdcm, londcm read (1, 10, end=999) expo, sect, stat, cast, date, time, 1 latdcm, londcm, depth 10 format (2X, A8, 3X, A3, 5X, I3, 7X, I1, 3X, A6, 3X, A4, 5X, 1 F6.3, 4X, F7.3, 4X, I4) Stated in tabular form, the contents include the following: _________________________________________________________________________________ Variable Variable Variable Starting Ending type width column column _________________________________________________________________________________ expo Character 8 3 10 sect Character 3 14 16 stat Numeric 3 22 24 cast Numeric 1 32 32 date Character 6 36 41 time Character 4 45 48 latdcm Numeric 6 54 59 londcm Numeric 7 64 70 depth Numeric 4 75 78 _________________________________________________________________________________ where expo is the expocode of the cruise (i.e., 06MT18/1); sect is the WOCE section number (i.e., A1E); stat is the station number (values range from 558 to 622); cast is the cast number; date is the sampling date (month/day/year); time is the sampling 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). met18.dat (File 6) This file provides hydrographic, carbon dioxide, and chemical data for the 61 stations occupied during R/V Meteor Cruise 18/1. Each line consists of a station number; cast number; sample number; bottle number; CTD pressure and temperature; potential temperature; reversing thermometer reading; CTD salinity; bottle salinity; concentrations of oxygen, silicate, nitrate, nitrite, phosphate, total carbon dioxide, and total alkalinity; and data quality flags. The file is sorted by station number and pressure and may be read by using the following FORTRAN 77 code (contained in met18dat.for, File 3): CHARACTER bot*3, qualt*10 INTEGER sta, cast, samp REAL pre, ctdtmp, theta, revtmp, ctdsal, salt, oxygen, silcat REAL nitrat, nitrit, phspht, tcarb, talk OPEN (unit=1, file='met18.dat') OPEN (unit=2, file='met18.data') write (2, 5) read (1, 10, end=999) sta, cast, samp, bot, pre, ctdtmp, 1 revtmp, ctdsal, theta, salt, oxygen, silcat, nitrat, nitrit, 2 phspht, talk, tcarb, qualt 10 format (5X, I3, 7X, I1, 6X, I2, 5X, A3, 2X, F6.1, 1X, F9.4, 1 1X, F8.3, 2X, F9.4, 1X, F9.4, 1X, F9.4, 2X, F6.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, A10) 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 23 24 bot Character 3 30 32 pre Numeric 6 35 40 ctdtmp Numeric 9 42 50 revtmp Numeric 8 52 59 ctdsal Numeric 9 61 69 theta Numeric 9 71 79 salt Numeric 9 81 89 oxygen Numeric 6 92 97 silcat Numeric 7 99 105 nitrat Numeric 7 107 113 nitrit Numeric 7 115 121 phspht Numeric 7 123 129 talk Numeric 7 131 137 tcarb Numeric 7 139 145 qualt Character 10 148 157 _________________________________________________________________________________ where 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 (deg. C); revtmp is the reversing thermometer reading (deg. C); ctdsal*is the CTD salinity [on the Practical Salinity Scale (PSS)]; theta is the potential temperature (deg. C); salt* is the bottle salinity; oxygen*is the oxygen concentration (umol/kg); silcat*is the silicate concentration (umol/kg); nitrat*is the nitrate concentration (umol/kg); nitrit*is the nitrite concentration (umol/kg); phspht*is the phosphate concentration (umol/kg); talk* is the total alkalinity concentration (umol/kg) ; tcarb* is the total carbon dioxide concentration (umol/kg); qualt is a 10-digit character variable that contains data quality flag codes for parameters flagged by an asterisk (*) in the output file. Quality flag definitions: 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. uwpco2.dat (File 7) This file contains underway pCO2 measurements taken along the cruise track during the R/V Meteor Cruise 18/1. Each line of the file contains a sampling date; sampling time; latitude; longitude; and measurements of sea surface salinity, temperature, and pCO2. The file is sorted by date and time and can be read by using the following FORTRAN 77 code (contained in uwpco2.for, File 4): INTEGER day, month, year CHARACTER time*5 REAL latdcm, londcm, salt, temp, pco2 OPEN (unit=1, file='uwpco2.dat') OPEN (unit=2, file='uwpco2.data') write (2, 5) read (1, 10, end=999) day, month, year, time, latdcm, 1 londcm, salt, temp, pco2 10 format (I2, 2X, I1, 2X, I4, 2X, A5, 3X, F6.3, 3X, F7.3, 3X, 1 F7.4, 2X, F5.2, 2X, F5.1) Stated in tabular form, the contents include the following: _______________________________________________________________________________ Variable Variable Variable Starting Ending type width column column _______________________________________________________________________________ day Numeric 2 1 2 month Numeric 1 5 5 year Numeric 4 8 11 time Character 5 14 18 latdcm Numeric 6 22 27 londcm Numeric 7 31 37 salt Numeric 7 41 47 temp Numeric 5 50 54 pco2 Numeric 5 57 61 _______________________________________________________________________________ where day is the sampling day; month is the sampling month; year is the sampling year; time is the sampling 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); salt is the sea surface salinity; temp is the sea surface temperature (deg. C); pco2 is the sea surface pCO2 (uatm). 8. VERIFICATION OF DATA TRANSPORT The data files contained in this NDP can be read by using the FORTRAN 77 data retrieval programs provided. Users should visually examine each data file to verify that the data were correctly transported to their systems. To facilitate the visual inspection process, partial listings of each data file are provided in Tables 6-8. Each of these tables contains the first and last five lines of a data file. Table 6. Partial listing of met18sta.inv (File 5) First five lines of the file: 06MT18/1 A1E 558 1 090591 1346 60.000 -42.507 185 06MT18/1 A1E 559 1 090591 1607 59.967 -42.175 504 06MT18/1 A1E 560 1 090591 1855 59.930 -41.853 1823 06MT18/1 A1E 561 1 090591 2242 59.895 -41.510 1898 06MT18/1 A1E 562 1 090691 0251 59.863 -41.200 2042 Last five lines of the file: 06MT18/1 A1E 618 2 092091 1657 52.335 -15.500 2834 06MT18/1 A1E 619 1 092091 2251 52.332 -15.218 1262 06MT18/1 A1E 620 1 092191 0220 52.333 -14.932 839 06MT18/1 A1E 621 1 092191 0508 52.337 -14.643 417 06MT18/1 A1E 622 1 092191 0737 52.333 -14.253 335 Table 7. Partial listing of met18.dat (File 6) First five lines of the file: 558 1 12 B44 7.9 6.7531 -999.900 34.7076 6.7524 34.7090 301.9 2.34 6.54 0.16 0.60 -999.90 2086.3 2222244492 558 1 13 B42 8.0 6.7531 -999.900 34.7065 6.7524 34.7090 301.4 2.54 6.54 0.17 0.57 -999.90 2087.5 2222244492 558 1 11 B46 8.5 6.7571 6.754 34.7066 6.7563 34.7090 302.4 2.34 6.54 0.16 0.60 -999.90 2086.5 2222244492 558 1 14 K7 8.7 6.7511 -999.900 34.7059 6.7503 34.7090 301.6 2.54 6.54 0.16 0.58 -999.90 2087.8 2222244492 558 1 10 B45 26.9 6.2526 -999.900 34.6606 6.2503 34.6650 302.9 2.73 7.23 0.18 0.63 2354.00 2091.5 2222244422 Last five lines of the file: 622 1 5 B49 149.2 10.0789 -999.900 35.4284 10.0614 35.4340 248.5 5.47 12.21 0.00 0.79 -999.90 -999.9 2222222299 622 1 4 B43 197.5 9.9849 9.988 35.4317 9.9619 35.4560 250.5 4.98 12.11 0.01 0.79 -999.90 -999.9 2222222299 622 1 3 K30 248.0 9.9720 -999.900 35.4517 9.9430 35.4560 251.1 4.98 11.82 0.00 0.77 -999.90 -999.9 2222222299 622 1 2 B46 296.4 9.8781 9.882 35.4570 9.8436 35.4610 241.3 7.32 12.50 0.01 0.86 -999.90 -999.9 2222222299 622 1 1 K31 316.0 9.8701 -999.900 35.4589 9.8333 35.4620 239.1 8.01 12.60 0.01 0.87 -999.90 -999.9 2222222299 Table 8. Partial listing of uwpco2.dat (File 7) First five lines of the file: 3 9 1991 20:20 62.666 -30.026 34.9400 9.13 294.3 3 9 1991 20:25 62.660 -30.057 34.9300 9.30 303.4 3 9 1991 20:30 62.655 -30.088 34.9267 9.37 307.9 3 9 1991 20:35 62.648 -30.120 34.9150 9.40 306.6 3 9 1991 20:40 62.640 -30.151 34.9133 9.40 305.3 Last five lines of the file: 22 9 1991 19:30 49.722 -4.782 35.3800 15.90 336.1 22 9 1991 21:00 49.747 -4.353 35.4600 15.70 340.2 22 9 1991 21:05 49.748 -4.329 35.4800 15.70 340.2 22 9 1991 21:10 49.750 -4.306 35.4950 15.65 337.2 22 9 1991 21:15 49.751 -4.282 35.4633 15.70 337.9