Numerical simulation of seasonal variations in circulations of the Bay of Bengal

Abstract

The seasonal variations in circulation at different layers of the Bay of Bengal (BOB) basin have been studied using multilayered regional ocean modeling system (ROMS). The model is simulated with climatological comprehensive ocean-atmospheric data set (COADS) wind and thermal forcing until annual cycle is reached. The northward flowing western boundary current (WBC) during spring and southward flowing east India coastal current (EICC) during autumn are developed due to the formation of anticyclonic and cyclonic Eddies respectively. The influence of Malacca Strait is prominent during winter season. The north equatorial current in the southern basin during winter to spring and southwesterly monsoon current (SMC) during summer are well simulated by the model. At 100 m depth current pattern along the Indian coast is similar to surface pattern in all the seasons. The 500 m depth current depicts the western boundary current in the winter season only. Many Eddies are simulated along the western coast of the basin during summer. The 1000 m current pattern indicates the existence of different Eddies in the basin for longer time. A strong anticyclonic Eddy persists near the head of Sri Lanka for almost every season. Andaman Sea is driven generally by one Eddy in the north and another in the south. Key words: Comprehensive ocean-atmospheric data set (COADS), western boundary current (WBC), east India coastal current (EICC), Bay of Bengal (BOB), regional ocean modeling system (ROMS), southwesterly monsoon current (SMC).