Storm-surge modelling for cyclone Mora in the northern Bay of Bengal

Abstract

Storm-surge modelling in the northern Bay of Bengal still remains a challenge due to the complex tidal nature and poor observational coverage. In this study, using satellite information, a coupled modelling system was developed which comprises Delft3D-Flow and simulated wave nearshore to simulate the storm surge associated with cyclone Mora 2017. In this study, followed by a hydrodynamic model development, a wind–pressure parametric Holland model was parameterised and validated using the Ascat MetOp B Level 2 wind speed. The significant wave height (SWH) was validated using CryoSat-2 and AltiKa-derived sea surface altimetry. The coupled model provides a realistic interpretation of storm surge. The tide–surge interaction in surge generation is largely dominated by shallow bathymetry and tide phase. The computed peak storm-surge height was 3–3·5 m along the landfall location – that is, Chittagong–Cox's Bazar coast and the maximum SWH of 4·2–5·3 m, formed surrounding the eye of the cyclone. The predicted surge height exhibits a reasonable match with the observed measurement and the obtained coefficient of determination is 0·87–0·91. Therefore, the developed storm-surge model with satellite-derived information is envisaged to support storm-surge modelling in data-scarce regions.