Abstract

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 (CTD) sensor], 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 routines, 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.

Reference

• 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. doi: 10.3334/CDIAC/otg.ndp066.