Background Information

To better understand the ocean's role in climate and climatic changes, several large experiments have been conducted in the past, and others are currently under way. The World Ocean Circulation Experiment (WOCE) is a major component of the World Climate Research Program. Although total carbon dioxide (TCO₂) is not an official WOCE measurement, a coordinated effort, supported in the United States by the U.S. Department of Energy (DOE) and the National Oceanic and Atmospheric Administration, is being made on WOCE cruises to measure the global, spatial, and temporal distributions of TCO₂ and other carbon-related parameters. The CO₂ survey goals include estimation of the meridional transport of inorganic carbon in a manner analogous to the oceanic heat transport (Bryden and Hall 1980; Brewer et al. 1989; Roemmich and Wunsch 1985), evaluation of the exchange of CO₂ between the atmosphere and the ocean, and preparation of a database suitable for both carbon-cycle modeling and the subsequent assessment of the anthropogenic CO₂ increase in the oceans. The final data set is expected to cover ~23,000 stations in the Atlantic, Pacific, and Indian oceans.

The Research Vessel (R/V) Meteor Cruise 18/1, from Reykjavik, Iceland, to Hamburg, Germany, from September 2 to 25, 1991, completed WOCE Zonal Section A1E (Fig. 1). It was one of a series of cruises starting in 1991 that are contributing to the WOCE North Atlantic Overturning Rate Determination (WOCE-NORD) program. The WOCE-NORD program is coordinated jointly by the Bundesamt f&uumlr Seeschiffahrt und Hydrographie (Hamburg) and the Institut f&uumlr Meereskunde (Hamburg). The sampling strategy of WOCE-NORD is to combine seasonally repeated hydrographic sections between southern Greenland and Iceland with current measurements from moored arrays. Program objectives include the direct determination of the overturning rates and the intensity of the meridional transports of mass, heat, and salt. Section A1E was chosen to be south of the major wintertime convection regions so as to avoid both water mass formation processes and shallow topography, either of which could cause difficulties in calculating volume transports.

This document describes the cooperative efforts of chemical oceanographers from Brookhaven National Laboratory (BNL) and the Institut f r Meereskunde Kiel (IFMK) to make high-quality CO₂ measurements along the WOCE Section A1E.