Effect of landfall location and coastal topography on surge response in the Northern Bay of Bengal

Abstract Storm surges caused by frequent cyclone events have posed severe threats to the inhabitants of the northern Bay of Bengal. In this study, a high-resolution, two-dimensional, hydrodynamic storm surge model was developed using the Semi-implicit Cross-scale Hydroscience Integrated System Model (SCHISM) to investigate storm surges in the Bay of Bengal. After validation, the storm surge of the study area was simulated for 11 idealized cyclone cases, the tracks of which were approximately perpendicular to the head of Bay of Bengal when landing at high-tide and low-tide time, respectively. The simulation results show that when landing at the high-tide time, the cyclone produced a peak surge height of about 85% of that when landing at the low-tide time, on average. It is also shown that when cyclone landed during the low-tide time, there was a delay of about 90-130 min for the arrival time of peak surge at the right side of the landfall position, compared with that landed during the high-tide time. Finally, we found that, for the area of the head of the bay, the surge response in the middle-eastern part was weak than that in other parts. This study demonstrates the importance of including the tide-surge interaction in the simulation of storm surge and provides the difference of the surge responses between different shore sections of the study area, which may be useful for the prediction and mitigation of the storm surge disaster.