Processes responsible for mixed layer variations near mesoscale eddies in the Bay of Bengal

Abstract

The present study investigates the mixed layer variations near mesoscale eddies in the Bay of Bengal (BoB) using satellite altimeter and Argo data. Furthermore, the factors responsible for sea surface variations near mesoscale eddies are analyzed using the mixed layer heat and salinity budgets estimated from Argo profiles. In the diagnostic mixed layer heat budget analysis, the entrainment term is parametrized based on the presence and absence of the barrier layer. The role of inversion and barrier layers on eddy-induced temperature variations is also examined near eddy locations. Results showed that anti-cyclonic eddies deepen mixed layer depth (MLD) and barrier layer thickness (BLT). Whereas, near cyclonic eddies shallower MLD and BLT is evident. However, MLD and BLT variations near mesoscale eddies are prominent during monsoon and winter seasons, respectively. Heat budget analysis near eddy locations depicts that surface heat fluxes and vertical entrainment are the primary factors responsible for temperature variations near mesoscale eddies. Similarly, the salinity budget analysis near eddy locations reveals that horizontal advection (stirring effect) is the predominant processes responsible for the salinity variations. The outcome of the present study is believed to be useful in validating and improving the eddy-resolving ocean models.