The Internal Tides of the Eastern Arabian Sea: A Seasonal Perspective

Internal tides (ITs) are internal waves characterized by tidal or quasi-tidal period, resulting from the interplay between barotropic tidal flow and submarine topography features in a stratified ocean. The dominant tidal constituents in this region are identified as M₂ and K₁ through in-situ observations from the moored buoys at AD08, AD09, AD10, and RAMA, with S₂ and O₁ following, respectively. A 3D Massachusetts Institute of Technology General Circulation model simulation is used to identify the key generation sites in the eastern Arabian Sea. The analysis revealed three primary locations: (1) the continental shelf-slope break off Mumbai (SD1), (2) the Lakshadweep region (SD2), and (3) the vicinity of the Maldives Islands (SD3). Among these, the SD1 and SD3 are identified as the major generation sites, collectively contributing approximately 70% of the total baroclinic energy within the study area. The energy budget analysis reveals that the semidiurnal energy conversion reaches its maximum in April at SD1 and in July at SD3, whereas the diurnal energy conversion exhibits peak values in October at SD1 and in July at SD3. SD2 demonstrated minimal seasonal variation in both semidiurnal and diurnal energy conversions. The energy flux patterns reveal south-westward propagation originating from the Mumbai region and westward propagation emanating from the Maldives. The findings highlight that the seasonal variability of ITs in the eastern Arabian Sea is predominantly governed by variations in stratification, offering valuable insights into the region's IT dynamics.