Dominant role of winds near Sri Lanka in driving seasonal sea level variations along the west coast of India

The strong seasonal cycle of sea level along the west coast of India (WCI) has important consequences for ecosystem and fisheries, and the Lakshadweep high/low in the southeast Arabian Sea is important for fisheries and the Indian summer monsoon. Previous studies suggested that WCI sea level variability is primarily driven by remote wind forcing from the Bay of Bengal and equatorial Indian Ocean through coastal Kelvin wave propagation. Using a linear ocean model, we demonstrate that wind forcing in a relatively small region around the southern tip of India and east of Sri Lanka contribute to similar to 60% of this variability. Wind variations from the rest of the Bay and the equator only account respectively for similar to 20% and similar to 10%. Sea level signals forced by the southern tip winds extend westward into the eastern Arabian Sea through Rossby wave propagation, with more than 50% contribution in the Lakshadweep high/low region.