This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO2) and total alkalinity (TALK) at hydrographic stations during the R/V John V. Vickers oceanographic cruise in the Pacific Ocean (Section P13). Conducted as part of the World Ocean Circulation Experiment (WOCE) and the National Oceanic and Atmospheric Administration's Climate and Global Change Program, the cruise began in Los Angeles, California, on August 4, 1992, with a transit line (Leg 0) to Dutch Harbor, Alaska. On August 16, the ship departed Dutch Harbor on Leg 1 of WOCE section P13. On September 15, the R/V John V. Vickers arrived in Kwajalein, Marshall Islands, for emergency repairs, and after 11 days in port departed for Leg 2 of Section P13 on September 26. The cruise ended on October 21 in Noumea, New Caledonia. Measurements made along WOCE Section P13 included pressure, temperature, salinity [measured by a conductivity, temperature, and depth sensor (CTD)], bottle salinity, bottle oxygen, phosphate, nitrate, nitrite, silicate, chlorofluorocarbons (CFC-11, CFC-12, TCO2, and TALK.

The TCO2 was measured by coulometry using a Single-Operator Multiparameter Metabolic Analyzer (SOMMA). The overall precision and accuracy of the analyses was ±2 µmol/kg. Samples collected for TALK were measured by potentiometric titration; precision was ±2 µmol/kg. The CO2-related measurements aboard the R/V John V. Vickers were supported by the U.S. Department of Energy.

The WOCE Section P13 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of two oceanographic data files, two FORTRAN 90 data-retrieval routine files, a documentation file, and this printed report, which describes the contents and format of all files as well as the procedures and methods used to obtain the data. Instructions on how to access the data are provided.

Keywords: carbon dioxide; TCO2; coulometry; World Ocean Circulation Experiment; Pacific Ocean; hydrographic measurements; alkalinity; carbon cycle.


  • Dickson, A. G., C. D. Keeling, P. R. Guenther, and J. L. Bullister. 2000. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V John V. Vickers Cruise in the Pacific Ocean (WOCE Section P13, NOAA CGC92 Cruise, August 4 - October 21, 1992), A. Kozyr (ed.). ORNL/CDIAC-128, NDP-075. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee, U.S.A. doi: 10.3334/CDIAC/otg.ndp075.

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