Evolution of the Great Whirl Using an Altimetry‐Based Eddy Tracking Algorithm

Abstract

AbstractTwenty‐three years of Archiving, Validation, and Interpretation of Satellite Oceanographic data absolute dynamic topography and HYbrid Coordinate Ocean Model sea surface height were analyzed with a focus on interannual variability of the Indian Southwest Monsoon in the southwest Arabian Sea. A new algorithm for identification and tracking of the Great Whirl (GW) is presented, which better accounts for the gyre's embedded environment than traditional mesoscale eddy tracking algorithms that use sea level observations. Based on this algorithm, the GW exhibits an average life span of 198 days, which is considerably longer than previous estimates, attributed primarily to a later termination date. A climatology of the GW evolution is created, peaking in early September. This study suggests a possible periodicity of the upper ocean structure during the mature phase of the GW and also highlights the sporadic nature of the decay phase.