FY 1997

Measurements of underway fCO₂ in the eastern equatorial Pacific on NOAA ships Malcolm Baldrige and Discoverer from February to September, 1994

Ho, D.T., R. Wanninkhof, J. Masters, R.A. Feely, and C.E. Cosca

NOAA Data Report ERL AOML-30, NTIS: PB97-169056INF, 52 pp (1997)

From February through September 1994 underway measurements of the fugacity (partial pressure) of carbon dioxide (fCO) were performed in the eastern equatorial Pacific as part of the Ocean Atmosphere Carbon Exchange Study (OACES) of the National Oceanic and Atmospheric Administration (NOAA). The measurements were performed with semi-autonomous instruments which measured the fugacity in the air and in the headspace of an equilibrator drawing water from the bow of the ship, from which the fCO of the surface water is calculated. From the difference in fugacity in air and water, the CO flux from the equatorial Pacific can be estimated. On the NOAA ship Malcolm Baldrige the system measured three reference standards, three air values, and eight water values per hour. The system on the Discoverer measured three standards, one 19-minute average air sample and one 20-minute average water sample per hour. This report contains a description of the methodology and reduction of the fCO and ancillary measurements. The results from the cruises of the Malcolm Baldrige in the equatorial Pacific in the (boreal) spring and fall of 1994, and from the Discoverer along nominally 110°W in the spring of 1994 are shown in a series of graphs with fCO air and water versus latitude as top panel and temperature and salinity versus latitude as bottom panel. The full data sets and support measurements can be obtained either via anonymous FTP from: ftp://ftp.aoml.noaa.gov/pub/ocd/carbon/uweqpac94 or via the World Wide Web: http://www.aoml.noaa.gov/ocd/oaces/.