Seasonal Variability of Internal Tides and Associated Energy Budget Over the Eastern Arabian Sea: Observations and Modeling

Abstract

The seasonal variability of Internal tides (ITs) in the Eastern Arabian Sea was studied in detail using in-situ observations and numerical modeling. Moored buoy observations identified M₂ and K₁ as the predominant tidal constituents, succeeded by S₂ and O₁. The 3D- Massachusetts Institute of Technology General Circulation Model is used to study the seasonal changes in the generation, propagation, and dissipation of ITs. We found that ITs are primarily generated along the continental shelf-slope break, with prominent generation sites off Mumbai in the north, around the Lakshadweep region, and near the Maldives in the south. Stratification varies both seasonally and regionally, strengthening from north to south. The enhancement of IT available potential energy and horizontal kinetic energy is observed during the pre-monsoon season in the north and during the monsoon season in the south, attributed to increased stratification. Shelf-slope areas off Mumbai and near the Maldives contribute approximately 66% of the total barotropic-to-baroclinic energy conversion. Energy flux patterns indicate a southwestward propagation from the Mumbai region and a westward propagation from the Maldives. Semidiurnal energy conversion and associated fluxes generally exceed those of diurnal energy across most seasons. These findings underscore that seasonal variability is primarily driven by changes in stratification, offering essential insights into the dynamics of ITs in this region.