Tidal Circulation Studies Using Regional Model in the Bay of Bengal

Abstract

Ocean circulation is very much important for ocean engineering in terms of building offshore structures, navigation, renewable energy and designing marine instruments. This study discusses the impact of tides on ocean circulation using high-resolution (spatial resolution 1/9° with 45 vertical levels) Regional Ocean Modelling System (ROMS) for the coastal region of the Bay of Bengal (BoB). A climatological simulation is performed with Comprehensive Ocean-Atmosphere Data Set (COADS05) air–sea fluxes and ten major tidal components from TOPEX/POSEIDON global tidal model (TPXO7). The simulation reproduced the tidal elevations well as validated with observation (at R1, near Paradeep, Odisha). In the head bay (R2) and the Gulf of Martaban (R3), the broad continental shelf and shape of the coastline largely contribute the amplification of tidal currents, which are around 0.9 and 1.7 m/s, respectively. In the BoB, semi-diurnal tide M2 achieves the highest amplitude 320 cm, followed by the amplitude of S2 tide (120 cm) at R3. The tidal-driven current changes its direction in every 6 h, which indicates that the shallow water constituents have significant impact in the R2 and R3 regions. The vertical structures of the currents denote tidal-driven current in those regions are more baroclinic.