Evolution of a Sub-Mesoscale Eddy Leeward of Andaman Islands From HF Radars

Remotely sensed high-resolution ocean surface currents from high-frequency radars (HFRs) on the western Andaman Sea (AnS) reveals signature of a sub-mesoscale coastal anticyclonic eddy leeward of Little Andaman (LA) Island during August 4–9, 2017. This “Lee eddy” had a mean radius of ~11 km, negative values of normalized vorticity, divergence, and Okubo–Weiss (OW) parameter, and smaller values of strain. A term-by-term vorticity budget analysis suggests that the vortex stretching term and wind stress curl dominate during the evolution and demise of the Lee eddy than does advection.