Improved determination of Indian Ocean surface currents using satellite data

A diagnostic algorithm for determining the upper layer current in the tropical Indian Ocean (TIO) is presented in this study. The algorithm is based on quasi-linear and steady-state physics. The current in the upper layer consists of three components, namely geostrophic component, wind-driven (Ekman) component and buoyancy component. Each of these components is estimated from different satellite data. The geostrophic component is estimated from merged altimeter product. The Ekman component is estimated from ocean surface winds derived from Oceansat-2 Scatterometer (OSCAT), whereas the buoyancy component is estimated from sea surface temperature (SST) derived from a combination of infrared and microwave radiometers. The product derived for the year 2010 is compared with a similar product, known as Ocean Surface Current Analysis Real-Time (OSCAR), computed by the same algorithm, but with somewhat different data sets. Afterwards, the product is compared with currents measured by several buoys at different locations in the TIO and it is observed that the current variability is better captured by the data generated using the present algorithm.