ORNL/CDIAC-113 NDP-066 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) Contributed by Kenneth M. Johnson,* Bernd Schneider,** Ludger Mintrop,*** and Douglas W. R. Wallace,* *Brookhaven National Laboratory Upton, New York, U.S.A. **Baltic Sea Research Institute Warnemünde, Germany ***Institute for Marine Sciences Kiel, Germany Prepared by Alexander Kozyr**** Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory Oak Ridge, Tennessee ****Energy, Environment, and Resources Center The University of Tennessee Knoxville, Tennessee, U.S.A. Environmental Sciences Division Publication No. 4814 Date Published: November, 1998 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 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, D. W. R. Wallace, and A. Kozyr (ed.). 1998 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). ORNL/CDIAC-113, NDP-066. 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 total alkalinity (TALK) at hydrographic stations, as well as the underway partial pressure of CO2 (pCO2) during the R/V Meteor Cruise 22/5 in the South Atlantic Ocean (Section A10). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Rio de Janeiro on December 27, 1992, and ended after 36 days at sea in Capetown, South Africa, on January 31, 1993. Measurements made along WOCE Section A10 included pressure, temperature, and salinity [measured by conductivity, temperature and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12), TCO2, TALK, and underway pCO2. The TCO2 was measured by using two Single-Operator Multiparameter Metabolic Analyzers (SOMMAs) for extracting CO2 from seawater samples that were coupled to a coulometer for detection of the extracted CO2. The overall precision and accuracy of the analyses was ±1.9 µmol/kg. Samples collected for TALK were measured by potentiometric titration; precision was ±2.0 µmol/kg. Underway pCO2 was measured by infrared photometry with a precision of ±2.0 µatm. The work aboard the R/V Meteor was supported by the U.S. Department of Energy under contract DE-ACO2-76CH00016, and the Bundesministerium für Forschung und Technologie through grants 03F0545A and MFG-099/1. The R/V Meteor Cruise 22/5 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. Instructions on how to access the data are provided. Keywords: carbon dioxide; coulometry; World Ocean Circulation Experiment; South Atlantic Ocean; hydrographic measurements; alkalinity; partial pressure of carbon dioxide; carbon cycle PART 1: OVERVIEW 1. BACKGROUND INFORMATION The World Ocean Circulation Experiment (WOCE) Hydrographic Program (WHP) is a major component of the World Climate Research Program whose overall goal is to better understand 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 concentration of carbon dioxide (CO2) and its effect on the heat balance of the global atmosphere. The increasing concentration of this gas may intensify the earth's natural greenhouse effect and alter the global climate in ways that are not well understood. CO2 in the oceans is unevenly distributed because of poorly characterized and complex circulation patterns and biogeochemical cycles. Although total CO2 (TCO2) is not an official WOCE measurement, a coordinated effort, supported in the United States by the U.S. Department of Energy (DOE), is being made on WOCE cruises through 1998 to measure the global spatial and temporal distributions of TCO2 as well as other related parameters. Goals of the survey are to estimate the meridional transport of inorganic carbon in a manner analogous to the oceanic heat transport estimates (Bryden and Hall 1980; Brewer et al. 1989; Roemmich and Wunsch 1985) and to build a database suitable for carbon- cycle modeling and the subsequent estimation of anthropogenic CO2 increase in the oceans. The CO2 survey is taking advantage of the sampling opportunities provided by the WHP cruises during this period. The final data set is expected to cover ~23,000 stations. This report discusses the results of the research vessel (R/V) Meteor Cruise 22/5 along the WOCE zonal section A10 (along ~30° S). The expedition started in Rio de Janeiro, Brazil, on December 27, 1992, and ended in Capetown, South Africa, on January 31, 1993. This section is one of four contiguous zonal sections (A8, A9, A10, and A11) completed in the South Atlantic Ocean during the WOCE survey. The large-scale three-dimensional distribution of temperature, salinity, and chemical constituents, including the carbonate system parameters, will be plotted using the data from these sections. Knowledge of these parameters and their initial conditions will enable researchers to determine heat and water transport as well as carbon transport. An understanding of this transport will contribute to the understanding of processes that are relevant to climate change. This section in the South Atlantic subtropical gyre is especially relevant to CO2 transport because it crosses both the Brazil and the Benguela boundary currents. This data documentation is the result of the cooperative efforts of chemical oceanographers from Brookhaven National Laboratory (BNL), U.S.A; Baltic Sea Research Institute [Institut für Ostseeforschung (IOW)], Germany; and the Institute for Marine Sciences of University of Kiel [Institut für Meereskunde Kiel (IfMK)], Germany to make high-quality CO2 measurements during the R/V Meteor expedition in South Atlantic Ocean. 2. DESCRIPTION OF THE EXPEDITION 2.1 R/V Meteor, Technical Details and History The R/V Meteor is owned by the Federal Republic of Germany through the 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 (the 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 exercised by direct 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. The Meteor was completed in 1986 in Travemunde, Germany. The basic features of the vessel follow: Port of registration Hamburg Call sign DBBH Classification GL+100A4E2+MC Auto Operator University of Hamburg, Institute for Ocean Research Built 1985 1986 at Schlichting Werft, Travemunde Basic dimensions: Gross registered tonnage 3990 Net registered tonnage 1284 Displacement 4780 t Length overall 97.50 m Beam 16.50 m Draught maximum 5.60 m Service speed 12 kn Depth main deck 7.70 m Personnel Crew: 32; scientists: 30 Main engine 4 × Mak6M 322 = 4 × 1000 kW at 750 rpm Propulsion Diesel-electrical, tandem-motor = 2 × 1150 kW Fuel consumption Approximately 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, echo sounder synchronization and supervision, and data-processing facility Science quarters 20 laboratories on the main deck with ~400 m2 of working space for multidisciplinary research 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 1927, 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 navy surveying and fisheries protection duties. Meteor (II) was planned after the 1950s; it was operated by the Deutsche Forschungsgemeinschaft (German Science Community) in Bad Godesberg and the Deutsches Hydrographisches Institut (German Hydrographic Institute) in Hamburg. Commissioned in 1964, Meteor (II) participated in the International Indian Ocean Expedition. Multipurpose Meteor (III), used for the cruise described in this documentation, was completed in 1986, replacing Meteor (II). Based in Hamburg, it is used for German ocean research worldwide and for cooperative efforts with other nations in this field. The vessel serves scientists of all marine disciplines in all of the world's oceans. 2.2 R/V Meteor Cruise 22/5 Information R/V Meteor Cruise 22/5 information follows: Ship name Meteor Cruise/leg 22/5 WOCE Section A10 Location Rio de Janeiro, Brazil, to Capetown, South Africa Dates December 27, 1992, to January 31, 1993 Funding German Science Community; Federal Ministry of Research and Technology, Bonn, Germany; and U.S. DOE Chief Scientist Dr. Reiner Onken, IfMK Master Martin Kull Parameters measured Institution Principal investigators CTD,(1) salinity, XBT,(2) and XCP,(3) IfMK R. Onken Nutrients IOW, IfMK B. Schneider, and H. Johannsen Oxygen IOW, IfMK B. Schneider, and H. Johannsen Chlorofluorocarbons (CFCs) UBT(4) W. Roether, and A. Putzka Tritium, helium, and radiocarbon UBT W. Roether, and A. Putzka TCO2 BNL, IOW K. Johnson, and B. Schneider TALK IfMK L. Mintrop Underway pCO2 IOW B. Schneider ADCP5 IfMK R. Onken _________________________________________________ (1)Conductivity, temperature, and depth sensor. (2)Expendable bathythermograph. (3)Expendable current profiler. (4)University of Bremen, Tracer Oceanography Laboratory. (5)Acoustic Doppler current profiler. 2.3 Brief Cruise Summary On December 26, 1992, K. Johnson of BNL arrived in Rio de Janeiro, where he joined Drs. B. Schneider and L. Mintrop and their CO2 group consisting of A. Morak, U. Karbach, A. Korves, and J. Morlang who were already onboard the R/V Meteor. Setting up of the equipment began immediately with the coulometry systems located in the Universal Laboratory, the underway pCO2 system in the Geo-Laboratory, and the alkalinity system in one of the ship's chemistry laboratories. The R/V Meteor departed Rio de Janeiro at 6 p.m. on December 27, 1992. Work began almost immediately with ADCP and XBT measurements across the Brazil Current and the occupation of test station no. 620. Then R/V Meteor headed to waypoint B and once again crossed the Brazil Current, where additional ADCP and XBT measurements were made. After R/V Meteor crossed the Brazil Current for the second time, the ship began the hydrographic stations at waypoint C. Between waypoints C and B the interval between stations was ~10 nm, and after waypoint B it rose to ~30 nm. The CO2 sampling began at the test station no. 620. The 30° S parallel was reached at waypoint D, and for the next few weeks the R/V Meteor sailed eastward along the 30° S parallel, passing over portions of the Vema Channel, the eastern part of the Rio Grande Rise, the Argentine Basin, the southern Brazil Basin, the Mid- Atlantic Ridge, the Angola Basin, the Walvis Ridge, and the Cape Basin. There was a small interruption in the work schedule to allow a New Year's Eve celebration. On January 8, nets laid by Spanish fishing boats on the western edge of the Rio Grande Rise caused the R/V Meteor detour. (However, this meeting with the fishing boats also resulted in a trade between captains in which the R/V Meteor received fresh swordfish and tuna). A small northward jog was made over the Walvis Ridge in order to sample around topographical features. The intervals between stations as the ship steamed eastward varied between 9 and 45 nm to limit the difference between the bottom depth at consecutive station depths to 1000 m. At 11° 30' E, the ship veered slightly to the east-northeast in order to avoid the South African 200-nm exclusion zone because permission to sample in these waters had not been obtained. After this turn, the station resolution was reduced to 20 nm until the last station on the African shelf at a depth of ~200 m. The measurement phase concluded on January 28, 1993, and the R/V Meteor steamed to Capetown, where it arrived on the afternoon of January 30. Aside from some light rain and intermittent cloudiness at the beginning of the cruise, the weather remained mostly sunny with summer temperatures and calm seas throughout. Closer to the coast of Africa, swells of ~5 m originating from subantarctic low-pressure areas were experienced but without any loss of work time. Two Single-Operator Multiparameter Metabolic Analyzers (SOMMAs) were used for measuring TCO2 concentration during this cruise. One was supplied by BNL and another by the IfMK. In addition, two potentiometric alkalinity titrators from IfMK were run in parallel, and an infrared (IR)-based system for measuring underway pCO2 belonging to IfMK was deployed. The TCO2 concentration in 1425 samples was analyzed from 57 of 100 CTD stations (57%) occupied during the cruise (Fig. 2). In addition, 116 coulometric measurements for the Certified Reference Material (CRM) and duplicate analyses were made during the cruise. The TALK concentration in 665 samples was determined by potentiometric titration during the cruise. Not all stations could be sampled for TCO2 and TALK because of the time required for analysis; however, the goal of 50% station coverage for CO2 samples was surpassed, and on average 1.5 stations were sampled per day by the CO2 group. The standard WOCE parameters (oxygen, nutrients, and salinity) were analyzed on all samples, and the tracer samples included CFC's, helium, tritium, and radiocarbon. The underway pCO2 system operated continuously. 3. DESCRIPTION OF VARIABLES AND METHODS 3.1 Hydrographic Measurements Water samples were collected with a General Oceanics rosette equipped with twenty-four 10-L Niskin bottles mounted on a Neil Brown Mark III CTD instrument provided by the IfMK. For stations deeper then 3500 m, two separate CTD/rosette casts were launched. For stations with a depth less then 3500 m, one CTD/rosette cast of up to 24 bottles was lowered. Surface currents down to 300 m, surface temperature, and surface salinity were measured continuously during the cruise with a hull-mounted ADCP and a thermosalinograph. In between CTD stations, XBTs were routinely launched. Over the boundary currents, XBTs were launched every half hour, and over the Benguela Current, the XBT launches were supplemented with free-falling XCPs. No serious problems were experienced with the CTD/rosette systems during the cruise. Repeated checks on board and several careful verifications using the complete bottle data sets have been carried out, and the sampling pressures have been assigned to each sample. Reversing thermometers of both the electronic (SIS, Kiel) and the mechanical (Gohla Precision, Kiel) types were also read at the completion of each cast. The processing and quality control of CTD and bottle data followed the published guidelines in the WOCE Operations Manual (WHPO 91-1, 1991). The CTD pressure, temperature, and conductivity data were processed and corrected according to laboratory calibrations. Pressure values are expected to be accurate to ±3 dbar; temperature values to ±0.002°C. Salinity for selected Niskin bottles (about one in every three) was also determined on a Guildline Autosal model 8400A that was standardized weekly with International Association for the Physical Sciences of the Ocean (IAPSO) water. These data were also used to process the CTD data, and the final salinity data are expected to be accurate to ±0.002. Bottle oxygen was determined by Winkler titration after the technique of Carpenter (1965) with the modifications of Culberson et al. (1991), using standards and blanks run in seawater. The precision of the analyses determined from parallel analyses (n = 10) of samples at and well below saturation is ±0.4%. The concentrations of nitrate, nitrite, phosphate, and silicate dissolved in seawater were determined for samples collected in high-density polyethylene screw-capped bottles by a continuous-flow method with an autoanalyzer. Precision was as follows: silicate, ±1.3%; phosphate, ±1.5%; and nitrite/nitrate, ±1.1%. Preweighed standards were used to prepare the nutrient working standards aboard the ship. 3.2 TCO2 Measurements The TCO2 was determined by using two automated dynamic headspace sample processors SOMMA 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). Details concerning the coulometric titration procedure can be found in Huffman (1977) and Johnson et al. (1985). Samples were collected in 300-mL precombusted (450°C for 24 h) glass standard Biological Oxygen Demand (BOD) bottles and analyzed for TCO2 during the cruise. During the cruise the samples were not poisoned with HgCl2 as per normal operating procedure (DOE 1994), but they were analyzed within 24 h of collection. Before analysis, samples were kept in darkness in a cold room and subsequently thermally equilibrated for at least 3 h to the analytical temperature. Analyses of duplicate samples separated in time by up to 8 h showed no evidence of any significant biological consumption or production of CO2 during storage. The CRMs were supplied by Dr. A. Dickson of Scripps Institution of Oceanography (SIO) (DOE 1994) and were also routinely analyzed. CRMs from batches 7 and 11 were available for this work (batch 7: S = 37.120, TCO2 = 1926.41 ± 0.82 µmol/kg; batch 11: S = 38.5, TCO2 = 2188.77 µmol/kg). The CRMs were made from filtered sterile salt solutions spiked with Na2CO3, and their TCO2 concentrations were determined by vacuum-extraction/manometry in the laboratory of Dr. C. D. Keeling at SIO. Seawater introduced from an automated "to deliver" (TD) 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. The coulometers were adjusted to give a maximum titration current of 50 mA, and they were run 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 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 from the acid. Each system was controlled with an IBM-compatible personal computer equipped with two RS232 serial ports, a 24-line digital input/output card, and an analog-to-digital card. The latter were manufactured by Real Time Devices (State College, Pa.). These were used to control the coulometer, barometer (BNL system only), solid-state control relays, and temperature sensors, respectively. 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 0.01°C (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, 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 personal computer (PC) monitor. With the coulometers operated in the counts mode, conversions and calculations were made by using the SOMMA software rather than the programs and the constants hardwired into the coulometer circuitry. The BNL SOMMA-coulometry system was calibrated with pure CO2 by using hardware that consisted 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)]. This GCV was 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 the ambient temperature and pressure. 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 that determined coulometrically, the gas calibration factor (CALFAC), 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.), which 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). The "to deliver" volume (Vcal) of the BNL SOMMA sample pipette was determined (calibrated) gravimetrically during the cruise by periodically collecting aliquots of deionized water dispensed from the pipette into preweighed serum bottles. The serum bottles were crimp sealed and returned to shore, where they were reweighed on a model R300S (Sartorius, Göttingen, Germany) balance. 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) , (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. Vcal was calculated by using the following equation: Vcal = Mvac/d . (3) The Vcal of the pipette for the BNL system was 20.6114 ± 0.0024 mL (n = 23) at a mean temperature of 14.67°C (hereafter the calibration temperature tcal). During the cruise, the mean pipette temperature was 14.95 ± 0.97°C, and the vast majority of samples were analyzed at a measurement temperature (t) that was within 1°C of this calibration temperature. The sample volume (Vt) at the measured pipette temperature was calculated from the expression Vt = Vcal [1 + av (t - tcal)] , (4) where av is the coefficient of volumetric expansion for pyrex-type glass ( 1 × 10-5 °C-1) and t is the temperature of the pipette at the time of a measurement. The BNL coulometer was periodically electronically calibrated as described in Johnson et al. (1993, 1996) and the DOE Handbook of Methods (1994). Briefly, 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 to the theoretical number computed from the factory-calibration of the VFC [frequency = 105 pulses (counts) generated/sec 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 (intercept = 0) with a slope of 1. For the BNL coulometer, the mean electronic calibration slope during the R/V Meteor Cruise 22/5 was 0.999616 ± 0.000056 (n = 12, r.s.d. = 0.006%) with an intercept of 0.000533 µmol/min. From the factory calibration of the VFC and the value of the Faraday (96489 Coulomb/mol), a scaling factor of 4.82445 × 103 counts/µmol was derived. The theoretical number of micromoles of carbon titrated (M) from samples or the gas loops was M = [Counts/4824.45 - (Blank × Tt) - (INTec × Ti)]/SLOPEec , (5) where Tt is the length of the titration in minutes, Blank is the system blank in µmol/min, INTec is the intercept from electronic calibration in µmol/min, Ti is the time in minutes during the titration where current flow was continuous, and SLOPEec 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 correction applied only for the period of continuous current flow (usually 3 4 min) because the electronic calibration can be carried out only for periods of continuous current flow. The TCO2 concentration in µmol/kg was calculated from TCO2 = M × CALFAC × [1/(Vt × p )] × dHg × CFcrm , (6) where p is the density of sea water in g/mL at the measurement temperature and sample salinity calculated from the equation of state given by Millero and Poisson (1981), dHg is the correction for sample dilution with bichloride solution (for this cruise dHg = 1.0 for the BNL and Kiel analyses because HgCl2 was not used), and CFcrm is a correction factor based on the daily liquid calibration by CRM analysis (CFcrm = 1.0 for all BNL analyses; no correction based on the CRM data). The BNL SOMMA-coulometry system was equipped with a conductance cell (Model SBE- 4, Sea-Bird Electronics, Inc., Bellevue, Wash.) for salinity measurement as described by Johnson et al. (1993). The conductance cell was factory calibrated, but SOMMA-measured salinities were continuously compared with the CTD salinities to ensure that the salinities of the analyzed samples matched the assigned salinities. Generally, agreement between CTD and SOMMA salinities was 0.02 or better. A leak in the gas calibration hardware of the BNL system was discovered on January 12, 1993. It affected the gas calibrations by diluting the CO2 calibration gas during the gas calibration procedure so that CALFACs determined between December 28, 1992, and January 12, 1993, were in error by approximately +0.1%. These CALFACs caused an error of +2 µmol/kg in the CRM analyses. Repairs were made on January 12, and from this point through January 28, daily CALFACs were determined and used to calculate the values of CRM and TCO2. The mean CALFAC for the period January 12-28 was 1.004270 ± 0.000818 (n = 12 ). This CALFAC was used to recalculate the values of CRM and TCO2 for the period from December 28 through January 11. The IfMK system did not possess a gas calibration system, and gas calibration was not carried out during the cruise. This IfMK system was calibrated at the IfMK in Kiel prior to the cruise with liquid standards (Na2CO3 solutions) according to the method of Goyet and Hacker (1992). A mean CALFAC (1.005 ± 0.07%) was obtained in the laboratory from the ratio (true TCO2 / measured TCO2). This value was used in Eq. 6 to calculate the CRM and TCO2 values throughout the cruise. During the calibration and at-sea work, the pipette volume, Vcal (also determined prior to the cruise), used for the IfMK system was 25.2347 mL at 20.02°C (see Eq. 4 ). This TD pipette volume was not redetermined gravimetrically during the cruise. Instead, an additional CFcrm based on the daily (cell-specific) CRM results was used to account for changes in pipette volume and/or system response by multiplying the TCO2 sample results by the ratio (see Eq. 6): CFcrm = CRM (certified) / CRM (measured) In summary, the IfMK system was calibrated as follows: a daily (cell-specific) CFcrm was applied to the water sample analysis results based on a laboratory-determined constant CALFAC (1.005) and a constant value of Vcal (25.2347mL at 20.02°C). The IfMK coulometer was not electronically calibrated during the cruise, and the theoretical response (Slope = 1, Intercept = 0) was assumed in Eq. 5 for all calculations. Note, however, that the CRM analysis results from the IfMK system were calculated with CFcrm = 1 in order that the variability of the CRM analyses and the magnitude of CFcrm could be assessed. The first phase of the QC-QA procedure was an assessment of accuracy using the data from the CRM analyses. These data are summarized in Table 1. For the BNL system, during the period from December 29, 1992, through January 11, 1993, a constant CALFAC (1.004270) was used to calculate CRM TCO2, whereas between January 1 and 29, 1993, a daily (cell-specific) CALFAC was used to calculate CRM TCO2. For the IfMK system, a constant CALFAC (1.005) was used for all calculations. Table 1. Summary of CRM TCO2 determinations made during the R/V Meteor Cruise 22/5 --------------------------------------------------------------------------------------------------------- System No. Batch(a) Mean St.Dev. Diff(b) Dates CALFAC Outliers(c) (n) µmol/kg µmol/kg --------------------------------------------------------------------------------------------------------- BNL 14 7 1926.7 0.65 +0.27 12/29-01/11 Constant 1 BNL 16 11 2188.7 0.89 -0.11 01/12-01/28 Daily 0 IfMK 18 7 1928.1 1.57 +1.68 12/30-01/12 Constant 1 IfMK 11 11 2191 1.88 +2.20 01/13-01/28 Constant 3 --------------------------------------------------------------------------------------------------------- (a) The CRM were from Batch 7 and 11 with salinities of 37.12 and 38.50, and TCO2 of 1926.41 ± 0.82 µmol/kg (n = 13) and 2188.77 ± 0.56 µmol/kg (n= 5), respectively. (b) The mean difference between measured and certified TCO2. (c) An outlier is defined as a CRM analysis with an error > or= 5.0 µmol/kg. Mean errors in the BNL system were significantly lower than the consistently positive errors observed in the IfMK system. For the BNL system, an outlier was obtained on January 4 (CRM bottle no. 2), but a second CRM (no. 275) run on the same cell gave a satisfactory result, and this cell was subsequently used to run samples. For the IfMK system, outliers were observed on January 7 and 12 (no. 353 and no. 8). In each case, a second CRM analysis (no. 318 and 244) gave satisfactory results, and the system was operated as normal. On January 20 two consecutive CRM analyses (no. 370 and 112) were classified as outliers, but a third CRM (no. 312) analysis gave a satisfactory result and the system was operated. Overall, 5 of 64 CRM analyses from Table 1 (7.8%) were classed as outliers, but 4 of these 5 outliers were obtained on the IfMK system which was further evidence for the slightly better performance of the BNL system. The greater number of outliers on the IfMK system could possibly be the result of malfunctioning of the IfMK pinch valve as described earlier. In general, the CRM results on the BNL system were identical to the manometric reference analyses at SIO. The BNL system response remained very constant over the duration of the cruise whether an average CALFAC (12/28/92-01/11/93) or a cell-specific CALFAC (01/12/93-01/28/93) was used to calculate CRM TCO2. These results confirm a similar finding obtained when mean CALFACs were used to calculate the TCO2 data of the R/V Meteor Cruise 18/1 (WOCE Leg A1E) (Johnson et al. 1996). The second phase of the QA-QC procedure was an assessment of sample precision on each system (instrument-specific precision). The system precision data are given in Table 2. For these data, "within-sample" precision is the average absolute difference between two replicates analyzed from the same sample bottle, "between-sample" precision is the average absolute difference between duplicate sample bottles taken from the same Niskin bottle, and "between-Niskin" precision is the average absolute difference of analyses of samples taken from two Niskin bottles that were closed at the same depth. The IfMK group assessed instrument-specific precision by periodically running two replicates from the same bottle ("within-sample"), whereas precision on the BNL system was assessed by running one replicate from each of two sample bottles filled from the same Niskin bottle ("between-sample"). Table 2. Summary of sample precision for TCO2 analyses made during the R/V Meteor Cruise 22/5 ----------------------------------------------------------------------------------------------- System | Mean precision and St.Dev. (µmol/kg)(a) | Sp2 | | within-sample (n) | between-sample (n) | between-Niskin (n) | (K, n, d.f.) | ----------------------------------------------------------------------------------------------- BNL 0 1.04 ± 1.11 (53) 1.26 ± 1.41 (12) 1.07 (53, 106, 53) IfMK 1.16 ± 1.62 (46) 0.98 ± 0.36 (6) 1.53 ± 2.04 (5) 0.73 (6, 12, 6) Combined 1.03 ± 1.06 (59) 1.34 ± 1.55 (17) 1.04 (59, 118, 59) ----------------------------------------------------------------------------------------------- n (a)Mean precision is [ absSUM (x1 - x2)] / n, where n is the number of comparisons between duplicates x=1 analyses, x1 and x2. Table 2 shows that there was no significant difference between the precision estimated using the three different methods; however, the standard deviation of the between-sample estimates was the lowest of the three methods. The same pattern was found for the TCO2 data of the R/V Meteor Cruise 18/1 (WOCE Section A1E) when within-sample and between-sample precision were compared (see Johnson et al. 1996), and these data were also consistent with results for other WOCE Sections (Johnson et al. 1995; Johnson et al. 1996). For the instrument-specific Sp2, K is the number of between-sample samples analyzed on the same instrument, n is the total number of replicates analyzed from K samples, and n - K is the degrees of freedom (d.f.). The third phase of the QA-QC procedure was to assess the performance of the systems by comparing results from aliquots of the same sample analyzed on each system. The precedent was set by the R/V Meteor Cruise 18/1 TCO2 data set when two SOMMAs were also run in parallel to generate the data set (Johnson et al. 1996). For the R/V Meteor 18/1 data, a method-specific Sp2, assuming homogeneous variance, was calculated from aliquots of the same sample analyzed on each system. The same calculation was made for the applicable R/V Meteor Cruise 22/5 samples, and the method-specific precision (Sp2) for this cruise calculated from 31 such samples (K = 31, n = 2, d.f. = 31) was ±1.92 µmol/kg. This is a more conservative estimate of overall cruise-wide precision than the instrument-specific precision shown in Table 2. For any measurement, irrespective of the instrument it was made on, the precision was ±1.92 µmol/kg. This includes all sources of error-random as well as any uncorrected systematic errors (bias). Figure 4 (in the report) is a histogram that shows the frequency distribution of the differences between aliquots of 31 samples that were measured on both systems. The mean and standard deviation of the mean difference was 0.81 ± 2.46 µmol/kg (BNL - IfMK TCO2 results) with most of the differences falling within the ±1.0 µmol/kg range. The IfMK calibration procedure therefore appears to have been successful in eliminating any overall system bias seen for the IfMK CRM analyses given in Table 1. For the CRM, the BNL system (gas calibrated) gave more accurate results than the IfMK system (not gas calibrated), and no corrections have been made to any of the sample data analyzed on the BNL system based on the CRM results. In summary, the mean difference between aliquots of the same sample analyzed on both systems was < 1.0 µmol/kg, and the method-specific pooled variance (Sp2 = ±1.92 µmol/kg) calculated from Youden (1951) is a creditable estimate of precision and accuracy for the R/V Meteor Cruise 22/5 data set generated by two systems run in parallel but calibrated differently. The fourth step in the QA-QC procedure, the at-sea to on-shore comparison, involved analyzing replicates of the same sample in real time at sea and later, after storage, on-shore. This procedure was carried out on 14 samples collected at 7 stations. The on-shore analyses were made by vacuum extraction/manometry in the laboratory of Dr. C. D. Keeling at SIO. The results of the comparison are given in Table 3 (Guenther, et al., personal communications, 1998). On the BNL System the initial comparisons (Jan. 13-15, n = 4, mean error -1.93 µmol/kg) were consistent with the precision and accuracy (±1.92 µmol/kg) of the method, but larger differences were observed after January 15. The mean difference for the cruise was -3.54 µmol/kg (for the R/V Meteor Cruise 18/1, the corresponding results were -2.13 µmol/kg (n = 7) with a method-specific precision and accuracy of ±1.65 µmol/kg). Overall the ship-to- shore difference is clearly not depth dependent. The poorest results were the very negative differences for samples collected on January 17 at station 62 and run on the IfMK system. There were other reasons to suspect the accuracy of the shipboard analyses from station 62 made on the IfMK system, so these samples have been averaged separately in Table 3. Note that only 3 of the remaining 12 differences were within the analytical precision of the shipboard method and these occurred early on in the cruise; 6 of the 12 were essentially within 2 standard deviations (±3.84 µmol/kg), but 3 differed by more than 2 standard deviations. All of the differences were negative. The CRM differences were not nearly as large as the ship-to-shore sample differences. The length of time the samples were stored prior to analysis on-shore was also not correlated with the at-sea vs on-shore differences. The reason for the difference between shipboard and shore-based analyses remains to be determined. Table 3. Comparison of at-sea analyses of TCO2 by coulometry and the on-shore analyses of TCO2 by manometry on aliquots of the same sample ------------------------------------------------------------------------------------------ Date Station Niskin Depth At-sea On-shore Storage(a) Difference CRM (1993) (no.) (no.) (m) (µmol/kg) (µmol/kg) (mo) (µmol/kg) diff(b) ------------------------------------------------------------------------------------------ BNL analyses ------------------------------------------------------------------------------------------ 1/13 48 318 10.2 2045.68 2047.49 11 -1.81 0.18 1/13 48 308 3002 2188.44 2189.98 10 -1.54 0.18 1/15 54 323 10.7 2044.96 2047.51 5 -2.55 -0.76 1/15 54 301 2808 2200.83 2202.68 5 -1.85 -0.76 1/19 68 323 10.4 2064.83 2068.02 10 -3.19 -0.14 1/19 68 307 3003 2200.10 2203.27 10 -3.17 -0.14 1/21 76 208 12.4 2057.86 2060.61 4 -2.75 -1.12 1/21 76 306 3003 2203.31 2207.06 4 -3.75 -1.12 1/24 85 213 11.8 2041.48 2047.61 3 -6.13 -0.68 1/24 85 312 3002 2200.73 2207.66 4 -6.93 -0.68 1/27 93 213 12 2029.99 2033.69 3 -3.70 -0.39 1/27 93 305 3004 2200.52 2205.61 3 -5.09 -0.39 Mean (n = 12) 6 -3.54 -0.11 St.Dev. ±3 ±1.71 ±0.69 -------------------------------------------------------------------------------------- IfMK analyses -------------------------------------------------------------------------------------- 1/17 62 208 12 2046.45 2054.22 4 -7.77 2.04 1/17 62 307 3004 2190.57 2202.12 5 -11.55 2.04 Mean 4 -9.66 St.Dev. ±1 ±2.67 -------------------------------------------------------------------------------------- (a)Storage refers to the elapsed time (in months) between sample collection and on-shore analysis by manometry.. (b)The SIO difference between the determined and certified CRM TCO2 for the specific coulometer cell used to titrate the at sea replicate sample. The data given in Tables 2 and 3 suggested that further QA-QC analysis of the data was justified. As described above, the two SOMMA systems used during R/V Meteor Cruise 22/5 employed different calibration strategies, and the number of replicate samples analyzed on both instruments was insufficient to assess bias on a station-by-station basis. As an additional cross- check on the intercomparability of TCO2 concentrations measured using the two analytical systems, the correlation of the TCO2 was compared with other measured oceanographic parameters. Brewer et al. (1995) and Wallace (1995) have previously noted that strong multivariate relationships exist between TCO2 and other hydrographic parameters (e.g. temperature, salinity, oxygen, and nutrients). These relationships are remarkably robust over basin-scales and have been used to examine the temporal buildup of CO2 in the oceans (Wallace 1995; Wallace et al. 1996; Holfort et al. 1998) and to interpolate sparse data (Brewer et al. 1995). Multiple linear regressions were initially performed for TCO2 data collected from three geographical sections of the R/V Meteor Cruise 22/5. Earlier work had suggested that regression fits varied slightly from one ocean basin to another. The section was therefore broken down into three groups of stations: those occupied in zone 1 defined as being west of 13° W (west of the Mid-Atlantic Ridge; southern Brazil Basin); stations occupied in zone 2, defined as being between 13° W and 3° E (between the Mid-Atlantic and Walvis Ridges; Southern Angola Basin); and stations occupied in zone 3, defined as being east of 3 °E (east of the Walvis Ridge; Northern Cape Basin). For each group of stations, all samples collected from below 200 m for which TCO2 had been measured (on either system) were extracted, and a stepwise multiple linear regression was performed with TCO2 as the dependent variable and the wide range of other measured hydrographic parameters as independent variables. The regression models determined that only potential temperature, salinity, apparent oxygen utilization (AOU), and silicate were significant predictors [this is the same choice of parameters as found previously by Wallace (1995) for the WOCE Section A9 along 19° S]. In addition, a single regression was performed for all of the data collected below 200 m from the entire section. The regression parameters for these four different geographical groupings of stations (the defined zones 1, 2, and 3 and the entire section) are presented in Table 4. For each of these four geographical groupings, two sets of regression coefficients are presented: one was derived from a regression that employed the measured silicate concentration as an independent variable and one for a regression that did not use silicate as a predictor. This initial exercise was not particularly satisfactory, as illustrated by the regression coefficients that varied significantly from one geographical zone to another and depended on whether silicate was employed as a predictor (Table 4). For example, the AOU coefficient varied from 0.33 to 0.63 when silicate was employed as an independent variable, and it reached as high as 0.86 when silicate was not used as a predictor. The salinity coefficient was even more variable, ranging from 2 to +24. In general, the potential temperature, AOU, and salinity coefficients were stable across the geographical groupings when silicate was not used in the regression: the inclusion of silicate caused the other coefficients to vary significantly. Use of silicate as a predictor could also shift the coefficients for the other parameters outside of their "oceanographically reasonable" ranges. For example, the AOU coefficient, if interpreted to reflect the respiratory quotient for organic material, should be 0.68 (Takahashi et al. 1985), 0.69 (Anderson and Sarmiento 1994), or 0.77 (Redfield et al. 1963). Clearly the AOU coefficient derived from regression no. 2A falls well outside this accepted range. Likewise, even the sign of the salinity coefficient is variable. "Oceanographic reasoning" suggests that there should be a positive partial correlation between TCO2 and salinity because of the strong positive correlation between carbonate alkalinity and salinity in the ocean (the countervailing tendency of CO2 gas solubility to decrease with increasing salinity is a relatively minor effect). The use of silicate did significantly reduce the overall standard error of the predictions (Table 4) and eliminated or markedly reduced certain systematic patterns in the distribution of the residuals with depth (results not shown). Table 4. Summary of initial multiple regression results with (A) and without (B) silicate as an independent variable. ----------------------------------------------------------------------------------- Regression Longitude Intercept Coefficients Standard no. range Pot. temp. Salinity AOU SiO4 error ----------------------------------------------------------------------------------- 0A All section 1987.32 -4.296 4.045 0.62 0.482 4.37 0B All section 1370.40 -6.254 22.038 0.827 6.88 1A Zone 1 1975.58 -4.259 4.37 0.633 0.462 4.77 1B Zone 1 1395.65 -5.957 21.178 0.864 0.462 7.12 2A Zone 2 2858.72 -2.531 21.163 0.327 1.126 4.44 2B Zone 2 1316.58 -6.623 23.822 0.754 1.126 4.42 3A Zone 3 2201.00 -3.949 -2.246 0.621 0.538 2.65 3B Zone 3 1540.28 -7.049 17.431 0.764 0.538 7.76 --------------------------------------------------------------------------------- In order to examine further the influence of silicate, the residuals evaluated from regressions based upon only potential temperature, salinity, and AOU against silicate were plotted. This plot (not shown) showed that for silicate concentrations between 0 and ~40 µmol/kg, the residuals averaged zero and there was no discernible trend; however, for silicate concentrations greater than ~40 µmol/kg, there was a very clear positive correlation of the residuals with silicate. On the basis of this it was decided to define a new parameter, the "silicate index" (ISi), as ISi = ([SiO4] > 40) × ([SiO4] - 40) . This index is equal to zero for SiO4 concentrations less than 40 µmol/kg, and it is equal to [SiO4] - 40 when silicate is greater than or equal to 40 µmol/kg. The results of regressions using the silicate index, potential temperature, salinity, and AOU as independent variables, are presented in Table 5. It can be seen that use of the silicate index, rather than the silicate concentration, makes the regression coefficients for the other parameters much more consistent from one geographical zone to another (see Table 4). Given the overall consistency of fit, it is right to use a single regression equation to predict the TCO2 over the entire section (Regression no. 0, Table 5). The distribution of residuals arising from this single section-wide regression equation are presented separately for the three defined geographical zones in Figure 5. Separate symbols are employed for the residuals derived from measurements made on the BNL and IfMK SOMMA systems. In general, there was little or no systematic structure apparent in the residual distribution (except perhaps at the very low TCO2 concentrations that are found close to the surface where seasonal effects may be significant), and the regression fits the data from all three zones reasonably well. Table 5. Summary of multiple regression results when the Silicate Index (Isi) was used as a predictor ----------------------------------------------------------------------------------------- Regression Longitude Intercept Coefficients Standard No. range Pot. temp. Salinity AOU ISi error ----------------------------------------------------------------------------------------- 0 All section 1706.33 -5.747 12.474 0.722 0.434 4.59 1 Zone 1 1704.61 -5.565 12.443 0.746 0.422 4.98 2 Zone 2 1863.67 -6.075 8.217 0.618 0.77 4.17 3 Zone 3 1964.15 -5.867 5.135 0.688 0.464 2.99 ----------------------------------------------------------------------------------------- In order to assess the intercomparability of TCO2 measurements made on the two SOMMA systems on a station-by-station basis, the mean residuals (calculated for each station) have been plotted (Fig. 6 in report) on the basis of the section-wide fit. This plot permits an assessment of the overall consistency of the measured TCO2 with the other measured hydrographic parameters over the entire cruise. The plot demonstrates the following: 1. There is some slight spatial structure to the station-mean residuals, with the mean residual in zone 2 (12.9° W < longitude < 3° E) being ~1-2 µmol/kg higher than for the rest of the section. No corresponding trend in the CRM analyses on the BNL system was seen (see Fig. 3 in report), and it was therefore hypothesized that this slight variation is "real" and is associated with different origins for water masses in this zone. 2. In general, there is no consistent difference between the station-mean residuals on the basis of measurements made with the BNL and IfMK SOMMA systems. The overall consistency of the two sets of measurements appears to be better than ±2 µmol/kg, which is consistent with the accuracy and precision bounds (±1.9) for the overall data set. This confirms that the cruise-wide calibration of the TCO2 data analyzed with the two instruments was nearly identical. 3. Three stations (625, 46, and 62) appear to be outliers from the overall pattern. These stations have a mean residual that is significantly different from the overall mean of the station-mean residuals analyzed with the BNL SOMMA. All of these three stations were measured by means of the IfMK SOMMA. While the possibility could not be ruled out that these deviations arise from errors in the measurement of the independent variables used in the regressions (e.g., the oxygen or silicate analyses or from "real" oceanographic variability), it was hypothesized that they were the result of calibration error of the TCO2 analysis at these stations. Given the approach used to calibrate the IfMK SOMMA, such deviations could arise from a single incorrect analysis of a CRM which would cause the correction factor (CFcrm in Eq. 6) for an entire station to shift based on an incorrect analysis. The BNL SOMMA analyses were less prone to such errors because the primary calibration was based on analyses of pure CO2 (gas calibration) with the CRM analyses being used as an independent cross-check on this primary calibration. With this approach, any calibration errors that may lead to systematic errors for an entire station are more likely to be identified and corrected. The residual intercomparison confirms that the overall quality of the combined BNL and IfMK data set is very high. However, three anomalous stations were identified. The TCO2 results at station 62 appear to be low by 5-7 µmol/kg. This station was also sampled for on-shore manometric analyses, and the results in Table 3 confirm that, whereas other stations had a mean (ship-shore) difference of -3.54 µmol/kg (±1.71 µmol/kg), the shipboard analyses from station 62 were 8-12 µmol/kg lower than the shore-based results. Therefore it was concluded from these two independent lines of evidence that the station 62 results are too low, and they have been flagged as incorrect in the original data file. On the basis of the residual analysis, the TCO2 results at station 46 may also be high by ~ 2-4 µmol/kg ,and TCO2 results from station 625 may be high by as much as 14 µmol/kg. However, there is no independent way to assess the data from these stations, and the anomalous residual could be "real" as a result of error in the predictor variables. Therefore, the TCO2 data from these stations have been flagged as "questionable." Only these three stations have been flagged; the data collected at the remaining 51 stations that were sampled for TCO2 appear to be internally consistent. 3.3 TALK Measurements A total of 665 samples for TALK measurements were collected in 500 mL bottles from 26 stations with the same precautions as for TCO2. The bottles were stored in the dark at 4°C and analyzed within 24 hours. The samples were transferred into a closed titration cell with a volume of approximately 120 mL and titrated at 25 ± 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 that waited for stable emf-readings before adding the next acid increment. The titration curve was analyzed through a modified GRAN-plot method described by Stoll et al. (1993) that used the carbonic acid constants of Goyet and Poisson (1989) and that takes into account the silicate and phosphate concentrations of the sample to obtain the titration alkalinity. The precision of the method was ±2.0 µmol/kg as determined by replicate analyses of samples. Standardization was accomplished with NaCO3 standards in NaCl solutions corrected for the blank arising from impurities in the salt. No reference materials were analyzed for alkalinity during this cruise. 3.4 Underway pCO2 Measurements Underway pCO2 was measured by the method of Schneider et al. (1992). Surface seawater was continuously pumped at a rate of 200-300 mL/min into a glass equilibrator with a volume of approximately 300 mL. The seawater was equilibrated with continuously circulating air entering the bottom of the equilibrator through a frit from a closed loop system. The latter included a heat exchanger to keep the air at the sample temperature, a filter and water trap, and an infrared analyzer (Siemens, Ultramat 5F) to determinate the CO2 content of the equilibrated air. The IR analyzer and the equilibrator temperature sensor were connected to a PC and to an analog recorder for data display and preservation. The time constant for the equilibration was about 3 min, which corresponded to a spatial resolution of 0.5 mi with the ship speed at 10 kn. Atmospheric air was periodically measured, and the system was calibrated every 12 h using calibration gases with CO2 mixing ratios of 252.5 and 412.8 ppm. Pressure corrections were made for the effect of water vapor and the pressure at the inlet of the IR analyzer, while the correction for the small difference between in situ and measuring temperature (<10°C) was made according to Gordon and Jones (1973). Fig. 7 in report shows the plot of underway measurements of temperature, salinity, sea surface pCO2, and air pCO2 during the R/V Meteor Cruise 22/5 in South Atlantic Ocean. 3.5 Secchi Disk Readings Between December 30, 1992, and January 28, 1993, as the ship moved eastward, Secchi disk readings were made during daylight hours when the opportunity arose. These data are given in Table 6. Table 6. Secchi Disk readings made during the R/V Meteor Cruise 22/5 ------------------------------------------------------------------------- Date Local time Latitude Longitude Conditions Depth (°S) (-°W, +°E) (m) ------------------------------------------------------------------------- 12/30/92 15:30 27°55 -46°40 clear 25 12/31/92 12:00 28°05 -45°56 clear 30 01/01/93 17:00 28°50 -43°35 cloudy 19 01/03/93 12:30 30°00 -40°00 cloudy 26 01/05/93 15:30 30°00 -36°10 clear 33 01/06/93 13:00 30°00 -34°00 partly cloudy 30 01/07/93 13:00 30°00 -32°00 hazy 19 01/09/93 16:00 30°00 -27°00 hazy 29 01/15/93 18:00 30°00 -13°40 clear 31 01/16/93 13:00 30°00 -11°40 clear 42 01/18/93 13:00 30°00 -07°00 clear 42 01/20/93 13:00 30°00 -01°00 clear 37 01/23/93 16:30 29°45 05°06 sunny 32 01/28/93 14:00 28°37 14°41 sunny 17 01/28/93 17:00 28°30 15°00 sunny 7 ------------------------------------------------------------------------- 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 for researchers. The following information summarizes the data-processing and QA checks performed by CDIAC on the data obtained during the R/V Meteor Cruise 22/5 in the South 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 (WHPO) after quality evaluation. A FORTRAN 77 retrieval code was written and used to merge and reformat all data files. 2. To check for obvious outliers, all data were plotted 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. 3. To identify "noisy" data and possible systematic, methodological errors, property-property plots for all parameters were generated, carefully examined, and compared with plots from previous expeditions in the South Atlantic 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 < 1992 or > 1993; TIME < 0000 or > 2400; LAT < -25.000 or > 17.000; and LONG < -60.000 or > 20.000). 6. Station locations (latitudes and longitudes) and sampling times were examined for consistency with maps and 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 (NDP-066) is available free of charge from CDIAC. The data are available from CDIAC's anonymous file transfer protocol (FTP) area via the Internet. Please note: your computer needs to have FTP software loaded on it (this is built in to most newer operating systems). Commands used to obtain the database are >ftp cdiac.esd.ornl.gov or >ftp 128.219.24.36 Login: anonymous or ftp Password: YOU@your internet address Guest login ok, access restrictions apply. ftp> cd pub/ndp066/ ftp> dir ftp> mget (files) ftp> quit The complete documentation and data may also be obtained from CDIAC's Web site at the following URL: http://cdiac.esd.ornl.gov/oceans/doc.html For non-FTP data acquisitions (e.g., floppy diskette, 8-mm tape, CD-ROM, etc.), users may order through CDIAC's online ordering system (http://cdiac.esd.ornl.gov/pns/how_order.html) or contact CDIAC directly to request the data and choice of media. For additional information, contact CDIAC. Address: Carbon Dioxide Information Analysis Center Oak Ridge National Laboratory P.O. Box 2008 Oak Ridge, Tennessee 37831-6335 U.S.A. Telephone: (423) 574-3645 (Voice) (423) 574-2232 (Fax) Electronic mail: cdiac@ornl.gov URL: http://cdiac.esd.ornl.gov/ 6. REFERENCES Anderson, L. A., and J. L. Sarmiento. 1994. Redfield ratios of remineralization determined by nutrient data analysis. Global Biogeochem. Cycles 8:65-80. 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., D. M. Glover, C. Goyet, and D. K. Shafer. 1995. pH of the North Atlantic Ocean: Improvements to the global model for sound absorption in seawater. J. Geophys. Res. 100:8761-76. 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 Chesapeake Bay Institute technique for the Winkler dissolved oxygen method. Limnol. Oceanogr. 10:141-43. Culberson, C. H., and R. T. Williams. 1991. A comparison of methods for the determination of dissolved oxygen in seawater. Report No. WHPO 91-2. WOCE Hydrographic Programme Office. Woods Hole Oceanographic Institution, Woods Hole, Mass. 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. Goyet, C., and S. D. Hacker. 1992. Procedure for calibration of a coulometric system used for total inorganic carbon measurements of seawater. Mar. Chem. 38:37-51. Holfort, J., K. M. Johnson, B. Schneider, G. Siedler, and D. W. R. Wallace. 1998. Meridional Transport if Dissolved Inorganic Carbon in South Atlantic Ocean. Global Biochem. Cycles. 12:479-99. Huffman, E. W. D., Jr. 1977. Performance of a new automatic carbon dioxide coulometer. Microchemical J. 22:567-73. Johnson, K. M., A. E. King, and J. McN. Sieburth. 1985. Coulometric TCO2 analyses for marine studies: An introduction. Mar. Chem. 16:61-82. Johnson, K. M., J. M. Sieburth, P. J. B. Williams, and L. Brändström. 1987. Coulometric TCO2 analysis for marine studies: Automation and calibration. Mar. Chem. 21:117-33. 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., 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., 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, Tenn. 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. Redfield, A. C., B. H. Ketchum, and F. A. Richards. 1963. The influence of organisms on the composition of seawater. M. N. Hill (ed). The Sea 2:26-77. 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. 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. 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. Takahashi, T., W. S. Broecker, and S. Langer. 1985. Redfield ratio based on chemical data from isopycnal surfaces. J. Geophys. Res. 90:6907-24. Wallace, D. W. R., K. M. Johnson, J. Holfort, and B. Schneider. 1996. Detection of the changing CO2 inventory in the ocean. U. S. WOCE Report. U. S. WOCE Implementation Report No. 8, Texas A&M University, College Station, Tex. Wallace, D. W. R. 1995. Monitoring global ocean carbon inventories. Ocean Observing System Development Panel, Texas A&M University, College Station, Tex. 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 comprise this NDP (see Table 7). Because CDIAC distributes the data set in several ways (e.g., via anonymous FTP and on floppy diskette), each of the seven files is referenced by both an ASCII file name, which is given in lower-case, bold-faced type (e.g., ndp066.txt) and a file number. The remainder of this section describes (or lists, where appropriate) the contents of each file. Table 7. Content, size, and format of data files File number, name, Logical File size and description records in bytes 1. ndp066.txt: 1,426 90,106 a detailed description of the cruise network, the three FORTRAN 77 data-retrieval routines, and the three oceanographic data files 2. stainv.for: 33 1,195 a FORTRAN 77 data-retrieval routine to read and print a10sta.txt (File 5) 3. a10dat.for: 49 2,278 a FORTRAN 77 data-retrieval routine to read and print a10dat.txt (File 6) 4. a10pco2.for: 47 2,500 a FORTRAN 77 data retrieval routine to read and print a10pco2.txt (File 7) 5. a10sta.txt: 195 15,405 a listing of the station locations, sampling dates, and sounding bottom depths for each of the 112 stations 6. a10dat.txt: 3,706 811,614 hydrographic, carbon dioxide, and chemical data from 112 stations 7. a10pco2.txt: 2,000 300,000 underway measurements of pCO2 along the cruise track _____ _______ Total: 4,433 878,496 7.1 ndp066.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. 7.2 stainv.for (File 2) This file contains a FORTRAN 77 data-retrieval routine to read and print a10sta.txt (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 a10sta.txt. c******************************************************************** c* FORTRAN 77 data retrieval routine to read and print the file * c* named "a10sta.txt" (File 5). * c******************************************************************** c*Defines variables* INTEGER stat, cast, depth REAL latdcm, londcm CHARACTER expo*10, sect*9, date*10, time*4 OPEN (unit=1, file='a10sta.txt') OPEN (unit=2, file='a10stat.txt') write (2, 5) c*Writes out column labels* 5 format (1X, 'STATION INVENTORY: R/V Meteor Cruise 22/5',/, 1 1X,'EXPOCODE',3X,'SECT',1X,'STNBR',2X,'CAST',9X, 2 'DATE',2X,'TIME',2X,'LATITUDE',2X,'LONGITUDE',2X, 3 'DEPTH',/) c*Sets up a loop to read and format all the data in the file* read (1, 6) 6 format (//////////) 7 CONTINUE read (1, 10, end=999) expo, sect, stat, cast, date, time, 1 latdcm, londcm, depth 10 format (A9, 4X, A3, 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, 4X, A3, 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 a10dat.for (File 3) This file contains a FORTRAN 77 data retrieval routine to read and print a10dat.txt (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 a10dat.txt. c******************************************************************** c* FORTRAN 77 data retrieval routine to read and print the file * c* named "a10dat.txt" (File 6). * c******************************************************************** CHARACTER qualt*11 INTEGER sta, cast, bot, pre, som REAL ctdtmp, ctdsal, theta, sal, oxy, silca REAL phspht, nitr, cfc11, cfc12, tcarb, talk OPEN (unit=1, file='a10dat.txt') OPEN (unit=2, file='a10data.txt') write (2, 5) c*Writes out column labels* 5 format (2X,'STNNBR',2X,'CASTNO',2X,'BTLNBR',2X, 1 'CTDPRS',2X,'CTDTMP',2X,'CTDSAL',3X,'THETA',4X, 2 'SALNTY',2X,'OXYGEN',2X,'SILCAT',2X,'PHSPHT',1X, 3 'NO2+NO3',3X,'CFC-11',3X,'CFC-12',2X,'TCARBN',1X, 4 'SOMMA#',2X,'ALKALI', 8X,'QUALT',/, 5 28X,'DBAR',2X,'ITS-90',2X,'PSS-78',2X,'ITS-90', 6 4X,'PSS-78',1X,4('UMOL/KG',1X),1X,'PMOL/KG',2X,'PMOL/KG', 7 1X,'UMOL/KG',8X,'UMOL/KG',12X,'*',/, 8 17X,'*******',17X,'*******',11X,5('*******',1X),1X, 9 '*******',2X,2('*******',1X),7X,'*******'12X,'*') c*Sets up a loop to read and format all the data in the file* read (1, 6) 6 format (////////////) 7 CONTINUE read (1, 10, end=999) sta, cast, bot, pre, ctdtmp, 1 ctdsal, theta, sal, oxy, silca, phspht, nitr, 2 cfc11, cfc12, tcarb, som, talk, qualt 10 format (5X, I3, 7X, I1, 5X, I3, 4X, I4, 1X, F7.4, 1 1X, F7.4, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F8.3, 1X, F8.3, 1X, F7.1, 3 5X, I2, 1X, F7.1, 2X, A11) write (2, 20) sta, cast, bot, pre, ctdtmp, 1 ctdsal, theta, sal, oxy, silca, phspht, nitr, 2 cfc11, cfc12, tcarb, som, talk, qualt 20 format (5X, I3, 7X, I1, 5X, I3, 4X, I4, 1X, F7.4, 1 1X, F7.4, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F8.3, 1X, F8.3, 1X, F7.1, 3 5X, I2, 1X, F7.1, 2X, A11) GOTO 7 999 close(unit=1) close(unit=2) stop end 7.4 a10pco2.for (File 4) This file contains a FORTRAN 77 data retrieval routine to read and print a10pco2.txt (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 a10pco2.txt. c******************************************************************** c* FORTRAN 77 data retrieval routine to read and print the file * c* named "a10pco2.txt" (File 7). * c******************************************************************** c*Defines variables* REAL jday, latdcm, londcm, sst, salt, airpre, airxco2 REAL airpco2, waterpco2 CHARACTER sect*3, date*10, time*5 OPEN (unit=1, file='a10pco2.txt') OPEN (unit=2, file='a10pco2.dat') write (2, 5) c*Writes out column labels* 5 format (2X,'UNDERWAY MEASUREMENTS R/V METEOR CRUISE 22/5',/, 1 2X,'SECT',9X,'DATE',4X,'TIME',5X,'JULIAN',3X,'LATIT',2X, 2 'LONGIT',3X,'SSTMP',2X,'SALNTY',2X,'ATMPRS',4X,'XCO2',5X, 3 'PCO2AIR',1X,'PCO2WATER',/,8X,'DAY/MO/YEAR',5X,'GMT',7X, 4 'DATE',5X,'DCM',5X,'DCM',3X,'DEG_C',5X,'PSS',4X,'ATM',2X, 5 'DRY_AIR_PPM',3X,'UATM',6X,'UATM',/) 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) sect, date, time, jday, latdcm, londcm, 1 sst, salt, airpre, airxco2, airpco2, waterpco2 10 format (3X, A3, 3X, A10, 3X, A5, 2X, F9.3, 1X, F7.2, 1X, 1 F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, F7.2, 3X, F7.1, 2 3X, F7.1) write (2, 20) sect, date, time, jday, latdcm, londcm, sst, 1 salt, airpre, airxco2, airpco2, waterpco2 20 format (3X, A3, 3X, A10, 3X, A5, 2X, F9.3, 1X, F7.2, 1X, 1 F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, F7.2, 3X, F7.1, 2 3X, F7.1) GOTO 7 999 close(unit=1) close(unit=2) stop end 7.5 a10sta.txt (File 5) This file provides station inventory information for each of the 112 stations occupied during R/V Meteor Cruise 22/5. Each line of the file contains an expocode, section number, station number, cast number, sampling date (month/date/year), sampling time, latitude, longitude, and sounding depth. The file is sorted by station number and can be read by using the following FORTRAN 77 code (contained in stainv.for, File 2): INTEGER stat, cast, depth CHARACTER expo*10, sect*3, 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, 4X, A3, 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 10 1 10 sect Character 3 14 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 expocode 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). 7.6 a10dat.txt (File 6) This file provides hydrographic, carbon dioxide, and chemical data for the 112 stations occupied during R/V Meteor Cruise 22/5. Each line consists of a station number, cast number, bottle number, CTD pressure, CTD temperature, CTD salinity, potential temperature, bottle salinity, oxygen, silicate, phosphate, nitrate plus nitrite, CFC-11, CFC-12, total CO2, SOMMA number, total alkalinity, and data-quality flags. The file is sorted by station number and pressure and can be read by using the following FORTRAN 77 code (contained in 10dat.for, File 3): CHARACTER qualt*11 INTEGER sta, cast, bot, pre, som REAL ctdtmp, ctdsal, theta, sal, oxy, silca REAL phspht, nitr, cfc11, cfc12, tcarb, talk read (1, 10, end=999) sta, cast, bot, pre, ctdtmp, 1 ctdsal, theta, sal, oxy, silca, phspht, nitr, 2 cfc11, cfc12, tcarb, som, talk, qualt 10 format (5X, I3, 7X, I1, 5X, I3, 4X, I4, 1X, F7.4, 1 1X, F7.4, 1X, F7.4, 1X, F9.4, 1X, F7.1, 1X, F7.2, 2 1X, F7.2, 1X, F7.2, 1X, F8.3, 1X, F8.3, 1X, F7.1, 3 5X, I2, 1X, F7.1, 2X, A11) 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 bot Numeric 3 22 24 pre Numeric 4 29 32 ctdtmp Numeric 7 34 40 ctdsal Numeric 7 42 48 theta Numeric 7 50 56 sal Numeric 9 58 66 oxy Numeric 7 68 74 silca Numeric 7 76 82 phspht Numeric 7 84 90 nitr Numeric 7 92 98 cfc11 Numeric 8 100 107 cfc12 Numeric 8 109 116 tcarb Numeric 7 118 124 som Numeric 2 130 131 talk Numeric 7 133 139 qualt Character 11 142 152 ------------------------------------------------------------------- The variables defined as follows: sta is the station number; cast is the cast number; bota is the bottle number; pre is the CTD pressure (in dbar); ctdtmp is the CTD temperature (in °C); ctdsala is the CTD salinity [on the Practical Salinity Scale (PSS)]; theta is the potential temperature (in °C); sala is the bottle salinity (on the PSS); oxya is the oxygen concentration (in µmol/kg); silcaa is the silicate concentration (in µmol/kg); phsphta is the phosphate concentration (in µmol/kg); nitra is the nitrate plus nitrite concentration (in µmol/kg); cfc11a is the trichlorofluoromethane-11 concentration (CCl3F) (in pmol/kg); cfc12a is the dichlorodifluoromethane-12 concentration (CCl2F2) (in pmol/kg); tcarba is the total carbon dioxide concentration (in µmol/kg); som is the SOMMA number; talk is the total alkalinity concentration (in µmol/kg); qualt is a 11-digit character variable that contains data-quality flag codes for parameters underlined with an asterisks (*******) in the file header. _________________________________ aVariables that are underlined with an 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. 7.7 a10pco2.txt (File 7) This file provides underway measurements of pCO2 during R/V Meteor Cruise 22/5. Each line of the file contains a sampling date (month/date/year), latitude, longitude, underway measurements of sea surface temperature, salinity, air pCO2, and water pCO2. The file is sorted by longitude and can be read by using the following FORTRAN 77 code (contained in a10pco2.for, File 4): REAL jday, latdcm, londcm, sst, salt, airpre, airxco2 REAL airpco2, waterpco2 CHARACTER sect*3, date*10, time*5 read (1, 10, end=999) sect, date, time, jul, latdcm, londcm, 1 sst, salt, pre, xco2, pco2a, pco2w 10 format (3X, A3, 3X, A10, 3X, A5, 2X, F9.3, 1X, F7.2, 1X, 1 F7.2, 1X, F7.2, 1X, F7.2, 1X, F7.1, 2X, F7.2, 3X, F7.1, 2 3X, F7.1) Stated in tabular form, the contents include the following: -------------------------------------------------------------------- Variable Variable Variable Starting Ending type width column column -------------------------------------------------------------------- sect Character 3 4 6 date Character 10 10 19 time Character 5 23 27 jday Numeric 9 30 38 latdcm Numeric 7 40 46 londcm Numeric 7 48 54 sst Numeric 7 56 62 salt Numeric 7 64 70 airpre Numeric 7 72 78 airxco2 Numeric 7 81 87 airpco2 Numeric 7 91 97 waterpco2 Numeric 7 101 107 -------------------------------------------------------------------- The variables are defined as follows: sect is the WOCE Section number; date is the sampling date (day/month/year); time is the sampling time (GMT); jday is the julian day of the century relative to 1900 with time of the day represented as a fractional day (i.e., noon on 1/1/1900 = 0.5); latdcm is the latitude of the sampling (in decimal degrees; negative values indicate the Southern Hemisphere); londcm is the longitude of the sampling (in decimal degrees; negative values indicate the Western Hemisphere); sst is the sea surface temperature (in °C); salt is the sea surface salinity (on the PSS); airpre is the atmospheric pressure (in atm); airxco2 is the observed mole fraction of pCO2 in air [in ppm (dry air)]; airpco2 is the air pCO2 (in µatm); waterpco2 is the sea surface water pCO2 (in µatm). 8. VERIFICATION OF DATA TRANSPORT The data files contained in this numeric data package can be read by using the FORTRAN 77 data retrieval programs provided. Users should visually examine each data file to verify that the data were correctly transported to their systems. To facilitate the visual inspection process, partial listings of each data file are provided in Tables 8, 9, and 10. Each of these tables contains the first and last twenty five lines of a data file. Table 8. Partial listing of a10sta.txt (File 5) First twenty-five lines of the file: *************************************************************************** * Source: K. Johnson B. Schneider * * D. Wallace Baltic Sea Research Institute * * Warnemunde, Germany * * Brookhaven National Laboratory * * Apton, New York, USA L. Mintrop * * Institute for Marine Sciences * * CDIAC NDP-066, September 1998 Kiel, Germany * *************************************************************************** *STATION INVENTORY: R/V METEOR *EXPOCODE SECT STNBR CAST DATE TIME LATITUDE LONGITUDE DEPTH 06MT22/5 A10 620 1 12/28/1992 1506 -25.645 -42.175 2290 06MT22/5 A10 622 1 12/30/1992 0626 -27.730 -47.385 177 06MT22/5 A10 623 1 12/30/1992 0914 -27.774 -47.207 326 06MT22/5 A10 624 1 12/30/1992 1129 -27.816 -47.026 536 06MT22/5 A10 625 1 12/30/1992 1348 -27.860 -46.847 758 06MT22/5 A10 626 1 12/30/1992 1755 -27.905 -46.670 1250 06MT22/5 A10 627 1 12/30/1992 2212 -27.950 -46.485 1693 06MT22/5 A10 628 1 12/31/1992 0224 -27.992 -46.308 2217 06MT22/5 A10 629 1 12/31/1992 0650 -28.039 -46.129 2408 06MT22/5 A10 630 1 12/31/1992 1140 -28.088 -45.939 2596 06MT22/5 A10 631 1 12/31/1992 1712 -28.153 -45.674 2782 06MT22/5 A10 632 1 12/31/1992 2240 -28.224 -45.408 2965 06MT22/5 A10 1 2 01/01/1993 0726 -28.418 -44.768 3509 06MT22/5 A10 2 1 01/01/1993 1315 -28.615 -44.222 3694 Last twenty-five lines of the file: 06MT22/5 A10 85 2 01/24/1993 1622 -29.746 7.621 5200 06MT22/5 A10 85 3 01/24/1993 1816 -29.736 7.627 5203 06MT22/5 A10 86 1 01/25/1993 0110 -29.746 8.465 5091 06MT22/5 A10 86 2 01/25/1993 0247 -29.744 8.465 5086 06MT22/5 A10 87 2 01/25/1993 1036 -29.750 9.297 5032 06MT22/5 A10 87 3 01/25/1993 1235 -29.755 9.307 4986 06MT22/5 A10 88 1 01/25/1993 1925 -29.748 10.148 4900 06MT22/5 A10 88 2 01/25/1993 2141 -29.747 10.185 4853 06MT22/5 A10 89 2 01/26/1993 0527 -29.749 10.980 4296 06MT22/5 A10 89 3 01/26/1993 0700 -29.748 10.981 4271 06MT22/5 A10 90 2 01/26/1993 1419 -29.752 11.830 4002 06MT22/5 A10 90 3 01/26/1993 1615 -29.755 11.852 3994 06MT22/5 A10 91 2 01/26/1993 2025 -29.622 12.171 3818 06MT22/5 A10 91 3 01/26/1993 2150 -29.621 12.187 3812 06MT22/5 A10 92 2 01/27/1993 0248 -29.497 12.467 3657 06MT22/5 A10 92 3 01/27/1993 0436 -29.489 12.474 3652 06MT22/5 A10 93 2 01/27/1993 0944 -29.373 12.795 3358 06MT22/5 A10 93 3 01/27/1993 1104 -29.372 12.815 3341 06MT22/5 A10 94 2 01/27/1993 1620 -29.243 13.114 3098 06MT22/5 A10 95 2 01/27/1993 2135 -29.119 13.428 2640 06MT22/5 A10 96 2 01/28/1993 0248 -29.001 13.735 2136 06MT22/5 A10 97 2 01/28/1993 0645 -28.879 14.045 1490 06MT22/5 A10 98 2 01/28/1993 0955 -28.752 14.366 461 06MT22/5 A10 99 2 01/28/1993 1240 -28.622 14.687 160 06MT22/5 A10 100 2 01/28/1993 1457 -28.503 14.999 174 Table 9. Partial listing of a10dat.txt (File 6) First twenty-five lines of the file *************************************************************************** * Source: K. Johnson B. Schneider * * D. Wallace Baltic Sea Research Institute * * Warnemunde, Germany * * Brookhaven National Laboratory * * Apton, New York, USA L. Mintrop * * Institute for Marine Sciences * * CDIAC NDP-066, September 1998 Kiel, Germany * *************************************************************************** * EXPOCODE 06MT22/5 R/V METEOR 22 LEG 5 WOCE SECTION A10 * * STNNBR CASTNO BTLNBR CTDPRS CTDTMP CTDSAL THETA SALNTY OXYGEN SILCAT PHSPHT NO2+NO3 CFC-11 CFC-12 TCARBN SOMMA# ALKALI QUALT * DBAR ITS-90 PSS-78 ITS-90 PSS-78 UMOL/KG UMOL/KG UMOL/KG UMOL/KG PMOL/KG PMOL/KG UMOL/KG UMOL/KG * * ******* ******* ******* ******* ******* ******* ******* ******* ******* ******* ******* * 620 1 324 2271 3.0620 34.9410 2.8832 34.9400 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 620 1 323 2271 3.0610 34.9410 2.8822 34.9400 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 620 1 322 2270 3.0600 34.9410 2.8813 34.9380 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 620 1 321 2270 3.0590 34.9420 2.8803 34.9370 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 620 1 320 2270 3.0590 34.9420 2.8803 34.9370 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 620 1 319 2270 3.0610 34.9420 2.8823 34.9370 -999.9 -999.90 -999.90 -999.90 0.019 0.180 -999.9 -9 -999.9 22299992499 620 1 318 2269 3.0610 34.9410 2.8824 34.9380 -999.9 -999.90 -999.90 -999.90 0.055 0.273 -999.9 -9 -999.9 22299992499 620 1 317 2269 3.0580 34.9420 2.8794 34.9400 -999.9 -999.90 -999.90 -999.90 0.221 0.228 -999.9 -9 -999.9 22299994499 620 1 316 2268 3.0630 34.9420 2.8844 34.9400 -999.9 -999.90 -999.90 -999.90 0.009 0.161 -999.9 -9 -999.9 22299992499 620 1 315 2268 3.0610 34.9410 2.8825 34.9400 -999.9 -999.90 -999.90 -999.90 0.032 0.040 -999.9 -9 -999.9 22299992299 620 1 314 2268 3.0590 34.9410 2.8805 34.9380 -999.9 -999.90 -999.90 -999.90 0.009 0.095 -999.9 -9 -999.9 22299992299 620 1 313 2267 3.0620 34.9420 2.8835 34.9400 -999.9 -999.90 -999.90 -999.90 0.016 0.113 -999.9 -9 -999.9 22299992299 Last twenty-five lines of the file 99 2 315 30 17.6020 35.2190 17.5970 -999.9000 226.2 3.24 0.36 3.40 -999.900 -999.900 2054.9 1 -999.9 22922229929 99 2 314 30 17.5930 35.2190 17.5880 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 313 30 17.5930 35.2200 17.5880 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 312 49 14.5570 35.2530 14.5498 -999.9000 210.0 4.75 0.67 8.74 -999.900 -999.900 2087.8 1 -999.9 22922229929 99 2 311 49 14.5320 35.2540 14.5248 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 310 49 14.5280 35.2560 14.5208 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 309 70 12.7110 35.1020 12.7016 -999.9000 204.3 5.67 0.88 12.55 -999.900 -999.900 2108.5 1 -999.9 22922229929 99 2 308 70 12.7200 35.1030 12.7106 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 307 70 12.7170 35.1030 12.7076 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 306 101 11.7430 34.9880 11.7301 -999.9000 200.0 7.09 1.06 15.15 -999.900 -999.900 2121.1 1 -999.9 22922229929 99 2 305 101 11.7490 34.9890 11.7361 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 304 100 11.7540 34.9900 11.7412 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 99 2 303 157 9.8380 34.7720 9.8201 -999.9000 162.6 13.43 1.59 21.95 -999.900 -999.900 2164.5 1 -999.9 22922229929 99 2 302 156 9.8350 34.7710 9.8172 34.7840 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22299999999 99 2 301 156 9.8320 34.7710 9.8140 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 100 2 324 13 18.3230 34.9820 18.3207 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 100 2 315 13 18.2810 34.9810 18.2787 -999.9000 248.8 3.02 0.35 1.27 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 313 30 16.7330 34.9500 16.7281 -999.9000 236.1 3.19 0.52 3.83 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 311 50 14.9330 35.0500 14.9255 -999.9000 213.9 4.34 0.70 8.33 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 309 70 12.3020 35.0480 12.2928 -999.9000 192.6 6.12 1.01 14.71 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 307 99 10.9840 34.8930 10.9718 -999.9000 185.6 8.40 1.23 17.81 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 306 100 11.0030 34.8980 10.9907 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 100 2 304 150 9.7980 34.7740 9.7808 -999.9000 145.3 15.62 1.71 23.15 -999.900 -999.900 -999.9 -9 -999.9 22922229999 100 2 302 160 9.7200 34.7640 9.7018 -999.9000 -999.9 -999.90 -999.90 -999.90 -999.900 -999.900 -999.9 -9 -999.9 22999999999 100 2 301 159 9.7270 34.7640 9.7089 -999.9000 143.8 16.41 1.73 23.61 -999.900 -999.900 -999.9 -9 -999.9 22922229999 Table 10. Partial listing of a10pco2.txt (File 7) First twenty-five lines of the file: ******************************************************************** * Source: K. Johnson B. Schneider * * D. Wallace Baltic Sea Research Institute * * Warnemunde, Germany * * Brookhaven National Laboratory * * Apton, New York, USA L. Mintrop * * Institute for Marine Sciences * * CDIAC NDP-066, September 1998 Kiel, Germany * ******************************************************************** *UNDERWAY MEASUREMENTS: R/V METEOR CRUISE 22/5 * DATE LATITUDE LONGITUDE TEMP SALT AIR_PCO2 WAT_PCO2 30/Dec/1992 -27.731 -47.385 24.70 34.83 -999.9 369.2 30/Dec/1992 -27.730 -47.384 24.67 34.83 -999.9 365.3 30/Dec/1992 -27.731 -47.384 24.67 34.84 -999.9 368.6 30/Dec/1992 -27.728 -47.383 24.68 34.82 -999.9 363.3 30/Dec/1992 -27.727 -47.383 24.69 34.78 -999.9 363.0 30/Dec/1992 -27.739 -47.342 24.59 35.19 -999.9 364.9 30/Dec/1992 -27.747 -47.311 24.61 35.45 -999.9 357.2 30/Dec/1992 -27.755 -47.280 24.61 35.68 -999.9 356.2 30/Dec/1992 -27.763 -47.249 24.56 35.94 -999.9 354.9 30/Dec/1992 -27.771 -47.218 24.66 35.88 -999.9 357.1 30/Dec/1992 -27.778 -47.185 24.61 35.99 -999.9 355.2 30/Dec/1992 -27.787 -47.153 24.54 36.19 -999.9 353.8 30/Dec/1992 -27.795 -47.123 24.67 36.10 -999.9 356.0 30/Dec/1992 -27.805 -47.092 24.64 36.43 -999.9 356.3 Last twenty-five lines of the file: 28/Jan/1993 -28.910 13.980 20.78 35.41 -999.9 331.9 28/Jan/1993 -28.890 14.010 20.77 35.38 -999.9 331.0 28/Jan/1993 -28.890 14.030 20.76 35.38 -999.9 329.4 28/Jan/1993 -28.880 14.040 20.76 35.39 -999.9 329.6 28/Jan/1993 -28.880 14.050 20.76 35.36 344.8 -999.9 28/Jan/1993 -28.890 14.050 20.76 35.34 -999.9 331.7 28/Jan/1993 -28.880 14.060 20.64 35.32 -999.9 331.4 28/Jan/1993 -28.870 14.090 20.62 35.35 -999.9 331.4 28/Jan/1993 -28.860 14.120 20.62 35.34 -999.9 330.5 28/Jan/1993 -28.840 14.150 20.66 35.32 -999.9 331.3 28/Jan/1993 -28.830 14.180 20.65 35.34 -999.9 331.5 28/Jan/1993 -28.810 14.210 20.61 35.36 -999.9 331.6 28/Jan/1993 -28.800 14.240 20.35 35.25 -999.9 330.3 28/Jan/1993 -28.790 14.270 20.16 35.31 -999.9 329.6 28/Jan/1993 -28.770 14.300 19.97 35.27 -999.9 327.6 28/Jan/1993 -28.760 14.330 20.34 35.26 -999.9 330.3 28/Jan/1993 -28.760 14.350 20.35 35.24 -999.9 329.9 28/Jan/1993 -28.750 14.380 20.21 35.34 345.2 -999.9 28/Jan/1993 -28.740 14.400 19.70 35.28 -999.9 327.5 28/Jan/1993 -28.730 14.430 19.94 35.21 -999.9 330.6 28/Jan/1993 -28.710 14.460 19.06 35.14 -999.9 331.7 28/Jan/1993 -28.700 14.500 18.87 35.12 -999.9 346.5 28/Jan/1993 -28.690 14.530 18.71 35.06 -999.9 350.6 28/Jan/1993 -28.680 14.560 18.69 35.10 -999.9 352.9 28/Jan/1993 -28.660 14.580 18.76 35.09 -999.9 352.6