Abstract

This data documentation discusses the procedures and methods used to measure total carbon dioxide (TCO₂) and the fugacity of CO₂ (fCO₂) at hydrographic stations during the R/V Meteor oceanographic cruise 28/1 in the South Atlantic Ocean (Section A8). Conducted as part of the World Ocean Circulation Experiment (WOCE), the cruise began in Recife, Brazil, on March 29, 1994, and ended after 35 days at sea in Walvis Bay, Namibia, on May 12, 1994. Instructions for accessing the data are provided.

TCO₂ was measured using two single-operator multiparameter metabolic analyzers (SOMMA) coupled to a coulometer for extracting and detecting CO₂ from seawater samples. The overall precision and accuracy of the analyses was ±1.17 µmol/kg. For the second carbonate system parameter, the fCO₂ was measured in discrete samples by equilibrating a known volume of liquid phase (seawater) with a known volume of a gas phase containing a known mixture of CO₂ in gaseous nitrogen (N₂). After equilibration, the gas phase CO₂ concentration was determined by flame ionization detection following the catalytic conversion of CO₂ to methane (CH₄). The precision of these measurements was less than or equal to 1.0%.

The R/V Meteor Cruise 28/1 data set is available free of charge as a numeric data package (NDP) from the Carbon Dioxide Information Analysis Center. The NDP consists of two oceanographic data files, two FORTRAN 90 data retrieval routine files, a readme file, and this printed documentation that describes the contents and format of all files as well as the procedures and methods used to obtain the data.

Keywords: carbon dioxide; coulometry; World Ocean Circulation Experiment; South Atlantic Ocean; hydrographic measurements; total carbon dioxide; fugacity of CO₂; carbon cycle.

Reference

• Johnson, K. M., K. Wills, A. Koertzinger, C. Neill, and D. W. R. Wallace. 2002. Carbon Dioxide, Hydrographic, and Chemical Data Obtained During the R/V Meteor Cruise 28/1 in the South Atlantic Ocean (WOCE Section A8, March 29 - May 12, 1994), A. Kozyr and T.W. Beaty (eds.). ORNL/CDIAC-135, NDP-079. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tennessee. doi: 10.3334/CDIAC/otg.ndp079