Meeting Documents

Seasonal Features and Potential Mechanisms of Submesoscale Processes in the Southern Bay of Bengal

Abstract

This study investigates the seasonal features and generation mechanisms of submesoscale processes (SMPs) in the southern Bay of Bengal (BoB) during 2011/12, based on the output of a high-resolution model, LLC4320 (latitude-longitude-polar cap). The results show that the southern BoB exhibits the most energetic SMPs, with significant seasonal variations. The SMPs are more active during the summer and winter monsoon periods. During the monsoon periods, the sharpening horizontal buoyancy gradients associated with strong straining effects favor the frontogenesis and mixed layer instability (MLI), which are responsible for the SMPs generation. The symmetric instability (SI) scale is about 3-10 km in the southern BoB, which can be partially resolved by LLC4320. The SI is more active during summer and winter, with a proportion of 40%-80% during the study period when the necessary conditions for SI are satisfied. Energetics analysis suggests that the energy source of SMPs is mainly from the local large-scale and mesoscale processes. Baroclinic instability at submesoscales plays a significant role, further confirming the importance of frontogenesis and MLI. Barotropic instability also has considerable contribution to the submesoscale kinetic energy, especially during summer.View Document (AGU) »