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| Abstract Submission No. | ABS-2022-07-0037 |
| Title of Abstract | Mixing and heat exchange in the Bay of Bengal: role of river fresh water and tidal forcing |
| Authors | Bijan Kumar Das*, TS Anandh, Arun Chakraborty, J Kuttippurath, Biswajit Haldar |
| Organisation | Department of Mathematics, Midnapore College (Autonomous). |
| Address | Dept of Mathematics, Midnapore College (Autonomous) Midnapore, West Bengal, India Pincode: 721102 Mobile: 9804855138 E-mail: dasbijankumar555@gmail.com |
| Country | India |
| Presentation | Oral |
| Abstract | The Bay of Bengal (BoB) exhibits a complex upper ocean dynamics owing to its semi-open basin shape, monsoon winds, equatorial remote influence, huge fresh water influx and tidal forcing. The river fresh water plays a significant role in the BoB on defining the upper ocean characteristics like mixed layer, stratification and density distribution. Again, the tidal forcing has substantial contribution on mixing and energy distribution. Earlier studies have reported the challenges to understand and represent the winds-fresh water-tide-eddy driven BoB mixing and air-sea interactions, which have a crucial role in the regional climate prediction. Therefore, this study aims to find the individual and combined role of river fresh water and tidal forcing on mixing and heat exchange in the BoB. The study includes four Regional Ocean Modelling System (ROMS) simulations; one climatological run and three other sensitivity experiments with river discharge, tide forcing and both together. The results show that the tidal buoyancy increases the upper layer temperature which eventually increases the upper ocean heat content and deepens the mixed layer. The river fresh water influx distributes the low saline water more horizontally and forms a well stratified layer, which is reduced by tidal vertical mixing in the combined forcing. The warmer ocean surface in the tidal forcing radiates more longwave, while the fresh water driven horizontal advection and tidal mixing in the combined forcing resulted maximum sensible and latent heat fluxes. Moreover, the study reveals that the upper ocean mixing as well as the heat exchanges in the BoB are largely modulated by the river fresh water and tides. |