Variability of mesoscale eddies and their kinetic energy in the Bay of Bengal using a high-resolution ocean model

Abstract

Oceanic eddies significantly contribute to the mixing of tracers such as temperature, salinity, and nutrients. Eddies are crucial to energy transfer and ocean circulation. The Bay of Bengal (BoB) is a naturally suitable location for intense eddy activity because of its distinct geographical and meteorological characteristics. Using a high-resolution regional ocean model, the mesoscale eddies in the BoB were detected, and their variability was examined in the current study. The model results show good agreement with the available observations. Both geometrical and dynamical approaches are used to identify and track the eddies, which aids in the removal of the frontal jets. The seasonal distribution of eddies, their spatial features, and propagation pathways are investigated. Following the identification and separation of the cyclonic eddy (CE) from the anticyclonic eddy (AE), the kinetic energy of each individual eddy is computed. In the western BoB, the variability of the East India Coastal Current (EICC) dictates eddy generation. The river discharge and bathymetry play a crucial role in determining eddy formation and its features in the northern BoB. Throughout the year, the radius of AEs is greater than that of CEs, reaching its maximum during the pre-monsoon (MAM) season. Compared to CEs, there is a stronger correlation between the size and energy of AEs. Eddie's share of the BoB's overall kinetic energy fluctuates from 7.2 % in March to 19.1 % in November. The seasonal contribution of eddies to the eddy kinetic energy (EKE) of the BoB is discussed, along with the varying strength and direction of winds and surface currents.