Résumé
As part of the U.S. JGOFS program in the Arabian Sea we have measured total CO (sub 2) (TCO (sub 2) ), and total alkalinity (TA) throughout the water column at selected station locations. In addition we measured the fugacity of CO (sub 2) in surface seawater and in the air above seawater along the cruise tracks. Between 10 degrees N and 20 degrees N, these measurements were repeated five times in January, March, July, November, and December 1995, and show different temporal variations of the carbonate properties in surface seawater depending upon the different regional hydrological and biological regimes. In order to estimate the relative importance of each process (physics, biology and thermodynamics) on the temporal carbon cycle in these regions, we use a 1-D process model initialized with the data from January 1995 and forced with climatological fields. The outputs of the model applied at three locations (10 degrees N 65 degrees E; 14.5 degrees N 65 degrees E; and 19 degrees N 65 degrees E) in the Arabian Sea are compared with US-JGOFS observations. The forcing terms and the "standard" biological parameters reproduce the CO (sub 2) cycle at 10 degrees N and 14.5 degrees N. At 19 degrees N, the "standard" biological activity has to be reduced by a factor two to approach the observed CO (sub 2) concentrations. The model outputs predict seasons of minimum and maximum fCO (sub 2) in surface seawater at time periods where no data are available in October and May/June, respectively. Abstract Copyright (1998) Elsevier, B.V.