DRIVING THE MERIDIONAL OVERTURNING IN THE INDIAN-OCEAN

Accumulating evidence points toward the surprising and puzzling conclu sion that the overall deep upwelling velocity in the Indian Ocean is s everal times bigger than that in the Pacific. Recent bulk-formula calc ulations suggest that the mean surface heat flux per unit area may be much greater into the Indian than into the Pacific Ocean. The hypothes is is therefore offered that the anomalously large meridional overturn ing in the Indian Ocean, an element of the global thermohaline circula tion, is driven locally by anomalously large heat-flux differential. A simple two-layered, two-dimensional model of the process is developed in order to compare relative upwelling rates to imposed heat fluxes. The comparison is promising, despite ambiguities in the upwelling evid ence and gross uncertainties in present heat-flux estimates.