Assimilation of satellite-derived ocean surface current in an Indian Ocean circulation model

Although satellites do not provide direct measurement of ocean surface currents, these currents can be indirectly inferred from satellite measurements. Such a product is regularly generated with the simultaneous use of three satellite-derived surface variables, namely sea surface height, sea surface winds and sea surface temperature. Ocean surface current has been assimilated in an Indian Ocean circulation model using the nudging technique, which involves extra surface stress acting on the ocean. This stress is the result of a difference between the satellite-derived currents and the model currents. The effect of the assimilation has been judged statistically. The impact has also been quantified in a free run following the assimilation. The assimilation has been found to exhibit a significant positive impact on the model simulation.