Improving Modeling of Tides on the Continental Shelf off the West Coast of India

Global tidal solutions are sometimes inaccurate in coastal regions. This is particularly true in some regions of the northern Indian Ocean, which are characterized by wide continental shelves and large tidal ranges. We show that these global solutions are inaccurate on the shelf region off Mumbai, off the west coast of India. In this region, the shelf is very wide, and it opens into the Gulf of Khambhat, where large tides are observed. Moreover, in regions of large semidiurnal tides in the Bay of Bengal, such as the head Bay, Gulf of Martaban, etc., global tidal solutions are not accurate. In the present work, we focus on the shelf region off the west coast of India. We used a new approach in developing a high-resolution hydrodynamic tidal model for the inner shelf region (8 degrees N to 22 degrees N). The open boundary of the model is aligned to the altimetry tracks, which allowed us to prescribe boundary conditions obtained directly from observations. We show that the tidal solutions at the coast are much improved compared with those obtained from the global solutions and that on the wide shelf portion and the Gulf of Khambhat the improvement has been considerable.