Numerical Simulation of Bay of Bengal Circulation Features from Ocean General Circulation Model

Abstract

The Bay of Bengal circulation features have been analyzed using a three-dimensional Ocean General Circulation Model (OGCM). The northward propagation of eastern boundary coastal Kelvin wave and its movement throughout the entire Bay is evident from the study. The trapping of Kelvin waves in the central Bay for many months causes warming of the central basin, which acts as a potential breeding ground of cyclones. The seasonal variations of circulation, temperature, and salinity have been reproduced by the model. These variations compare favorably with observations. The existence of a salt finger towards north and its eastward movement are two important results of the study. The cyclonic gyres in the Bay of Bengal during different months agree reasonably well with the SeaWiFS chlorophyll observations and indicate the upwelling zones over the basin. The presence of a subsurface Bay-of-Bengal dipole in summer monsoon months is another important result of the study.

Keywords:

• OGCM
• EICC
• Kelvin waves
• Rossby waves
• salt finger

Acknowledgements

This study is supported by the INDOMOD research project (POM, PR2007) of INCOIS under the Ministry of Earth Sciences, Government of India, and OCEANSAT-II utilization project (BBC, RP2008) of the Space Applications Center (Indian Space Research Organization). A few of the authors (S.P, A.C, P.C.P and S.K.S) are grateful to the Director, I.IT (Kharagpur) and Dean, SRIC for providing necessary academic facilities and support. The helpful suggestions provided by Prof. Abhijit Gangopadhyaya of UMSSD USA, Dr. P. K. Bhaskaran, and Dr. M. K. Dash are gratefully acknowledged. The authors also wish to express their gratitude to Mr. P. Sarkar and Mr. B. Chakraborty for their help during the course of this study.