Role of surface rainfall to the variability of extreme sea level along the eastern coast of Bangladesh

Abstract

Bangladesh is highly vulnerable to the adverse impacts of extreme sea levels (ESLs) because of its geographical location with low-lying coast. In addition, high discharge of huge rain water to the nearby coast may influence the ESL. The effects of different meteorological forcings like atmospheric pressure, wind-induced wave, and surges to ESL have been investigated intensively around Bangladesh. However, the role of surface rainfall to the ESL along the coast of Bangladesh remains unknown. In this study, the role of surface rainfall to the ESL was investigated for Cox's Bazar area along the eastern coast of Bangladesh. The ESL events were selected by applying the threshold of 500 mm height. The variations in SLA during seven days in prior to the ESL was predicted by multivariate regression using selected climatic variables of rainfall, sea level pressure, and wind. It was revealed that the prediction of ESL considering the contribution of rainfall outperforms the predictions without rainfall. The significant contribution of rainfall for prediction of ESL at Cox's Bazar, reflecting the hilly landscape at Cox's Bazar where a clear response of high surface runoff is expected. The findings suggest that the rainfall have an important effect to the ESL change along the eastern coast of Bangladesh. Therefore, incorporating rainfall effect is essential for better prediction of the ESLs which helps coastal management and reduction of hazards.