COHERENS:A Hydrodynamic Model Validated for the West Coast of India

COHERENS (COupled Hydrodynamical and Ecological model for REgioNal and Shelf seas), a 3D hydrodynamic multi-purpose model, has been implemented for the coastal and shelf seas of eastern Arabian Sea to study the flow characteristics. The model has been tested and verified with one month measurements of surface and bottom currents collected off Mangalore, Ratnagiri, Mumbai and Dwarka on the west coast of India (WCI). After calibration, the model was allowed to perform under tide and wind forcings. The flow characteristics at these select locations have been well reproduced by the model. A shift in current direction from south to southeast has been observed at several occasions, and this could be attributed to shamal events. The low amplitudes of the residual currents in the measurements off Mumbai and Dwarka suggest that the influence of the West India Coastal Current is weak or negligible in the northern part of the WCI and the currents are mainly tide-dominant. Certain discrepancies are noticed especially in the southern domain, off Mangalore, where the shallow water dynamics is not only driven by the local wind forcing and tides, but also by the remotely driven currents. In order to get a comprehensive picture of the prevailing dynamics, the model domain has to be extended to the entire Indian Ocean.