Dynamics and energetics of regional domain in the Bay of Bengal using Modular Ocean Model
Siddhesh Tirodkar*, Srinivas VL, Sridhar Balasubramanian, Manasa Ranjan Behera
Indian Institute of Technology Bombay
GMFL, Dept of Mechanical Engg., Indian Institute of Technology Bombay Mumbai, Maharashtra, India Pincode: 400076 Mobile: 9619055438 E-mail: firstname.lastname@example.org
The Bay of Bengal (BoB) is a unique domain, which experiences seasonal wind reversal and fresh water influx. The ocean processes in a regional domain play vital role in maintaining the ocean structure through complex interaction of flow dynamics and energetics. Many earlier studies foscused on the Bay of Bengal dynamics with coarser horizontal resolution and sponge lateral boundary condition. In this study, regional domain in the BoB basin, ranging from 75 E to 95 E and 10 S to 25 N, was used with two different horizontal resolutions, namely, 0.250 and 0.1250 with 1 m vertical resolution near the surface. Additionally, a radiation type Open Boundary Condition (OBC) for smooth exchange of fluxes across open ocean interaction is implemented. To study above objectives, Modular Ocean Model (MOM 5) developed by NOAA's Geophysical Fluid Dynamics Laboratory was used. The K-profile parameterization (KPP) mixing scheme was incorporated in the model setup to parameterize the vertical mixing. The model was forced with SODA data wind stress and world ocean atlas initial temperature and salinity profiles. The results from above study confirm successful implementation of radiation OBC near boundary and smooth exchange of fluxes across boundary. Conservation of mass was verified by model output variables. Obtained results provide better understanding of the ocean sub-surface mixing process due to the wind stress forcing. The finer resolution case (0.1250) observes the presence of small eddy near east coast of India which we failed to capture through 0.250 simulation. This proved as a successful attempt to go closer to resolving the meso-scale processes in Bay of Bengal. The ocean currents, sea surface temperature (SST) and sea surface salinity (SSS) are in good agreement with the SODA reanalysis data. Model parameterization performed well in simulating the seasonality in the ocean currents. The turbulent kinetic energy (TKE) was compared in both the resolutions and some interesting energetics were observed.