Impact of Cyclone Track Features and Tidal Phase Shift upon Surge Characteristics in the Bay of Bengal along the Bangladesh Coast

Mohammad Hussain,Yoshimitsu Tajima,Mohammed Hossain,Partho Das

doi:10.3390/jmse5040052

Abstract

The impact of cyclone track features (e.g., cyclone translation speed, cyclone path and cyclone landfall crossing angle) in combination with tidal phase shift upon surge characteristics have been investigated at the Bay of Bengal along the Bangladesh coast. A two-dimensional hydrodynamic model in a horizontal direction (2DH) coupled with a storm-surge model has been employed for the study. Numerical experiments with three different cyclone translation speeds show that when the surge height is directly forced by the cyclonic wind speed especially within the RWM (Radius of Maximum Wind), faster translation speed produces reduced surge height as the cyclone gets less time to force the water. On the other hand, at locations outside the RMW, surge waves travel as a propagating long wave where higher surges are produced by faster moving cyclones. It is found that surge arrival times are more and more affected by tidal phase when cyclone translation speed is reduced. Analysis of seven hypothetical parallel cyclone paths show that local bathymetry and complex coastline configurations strongly influence the surge height and surge arrival time along the Bangladesh coast. From the analyses of cyclone landfall crossing angles at the Khulna and Chittagong coasts, it is observed that surge durations are the smallest at both the coasts when the coastline crossing angles are the smallest.

Highlights

Cyclonic storm surges are considered as one of the deadliest and costliest natural disasters and they are sometimes referred as “the sea’s greatest killers” [1]
The present study focuses on the cyclone track features and tidal phase shift upon surge characteristics in the Bay of Bengal along the Bangladesh coast
The present study aims to focus on the impact of three cyclone track features: cyclone translation speed, cyclone path and cyclone landfall crossing angle, in combination with tidal phase shift upon surge characteristics

Summary

Introduction

Cyclonic storm surges are considered as one of the deadliest and costliest natural disasters and they are sometimes referred as “the sea’s greatest killers” [1]. Many of the coastal zones around the world, including megacities, are vulnerable to the impacts of accelerated global sea-level rise and other coastal implications of climate change, such as changing storm frequency [2]. Those areas located in deltas are susceptible to natural subsidence, which can be aggravated by anthropogenic activities [3]. Number of fatalities and property damage caused by a cyclonic storm surge event are related to category of cyclone or height of abnormal surge waves. The socioeconomic characteristics of coastal residents, population density, cyclone warning system, location and number of cyclone shelters, livestock shelters may significantly contribute to the vulnerability of the residents to cyclones [4]

Results

Discussion

Conclusion