MODEL-VALIDATED PARAMETRIZATION FOR AIR-SEA GAS TRANSFER IN THE NORTHINDIAN-OCEAN

Mixed-layer CFC-11 saturations measured in the northwestern Indian Oce an during the 1995 World Ocean Circulation Experiment (WOCE) along 17N are compared to those from a numerical model using three alternative parametrizations for the air-sea flux of CFC-11. The Wanninkhof [1992] gas flux parametrization for climatological winds gives gas saturatio ns which agree best with those observed. The observed and model mixed- layers are in equilibrium with the contemporary atmosphere to within 1 % (the experimental error) in the summer of 1995, excluding cold coast al upwelled waters. When the model is used to extend the space and tim e scales of the observations in the Arabian Sea, widespread supersatur ations of 5% due to weak winds and warming are predicted in the spring and fall, and undersaturations of 5% due to mixing in the winter. The model validation of CFC-11 transfer parametrization and investigation of temporal and spatial variability in saturation are applicable to t he physically-forced saturation variations of carbon dioxide and other gases of interest.