Delayed response of eddy kinetic energy build-up off Somali coast during summer monsoon

The Great Whirl (GW), a prominent anticyclonic gyre in the northwest Indian Ocean, is crucial in regional circulation and energy dynamics during the summer monsoon. Using satellite observations and a high-resolution ocean simulation, this study examines the mechanisms behind the growth and maintenance of Eddy Kinetic Energy (EKE) in the GW region. EKE peaks 55 days after the summer monsoon’s peak, a delay caused by energy transfer processes. Southwest wind forcing during the monsoon initiates the EKE growth, with the barotropic energy conversions from mean flows eventually dominating the energy input. Enhanced stretching and shear effects of the Somali Currents (SC) intensify barotropic instabilities, maintaining EKE even as monsoon winds weaken. The baroclinic energy conversions act as a secondary energy input, exhibiting a positive eddy buoyancy work (potential energy to kinetic energy) at the upwelling wedge regions northwest of the GW. Our study highlights the importance of internal energy transfer processes in modulating ocean circulation and energy dynamics off the Somali Coast, emphasizing eddy-mean flow interactions and potential-to-kinetic energy transfer in the Somali upwelling system.