Modeling Tropical Cyclone Storm Surge and Wind Induced Risk along the Bay of Bengal Coastline Using a Statistical Copula

Abstract

High winds, torrential rain, and storm surges from tropical cyclones cause massive destruction to property and cost the lives of many people. Among the coastal areas affected by these major natural calamities, the coastline of the Bay of Bengal (BoB) ranks as one of the most susceptible to tropical cyclone storm surge risk due to its geographical setting and population density, Bangladesh suffers the most. The purpose of this study is to describe the relationship between storm surge at the BoB and peak reported wind and describe the dependency structure between wind speeds and storm surges at that location. Various models have been developed to predict storm surge in this region but none of them quantify statistical risk with empirical data. This research demonstrates a methodology for estimating the return period of the joint hazard based on a bivariate copula model. An Archimedean Gumbel copula with Weibull and normal margins is specified for the result the coast of BoB can expect a cyclone with peak reported winds of at least 24 m s−1 and surge heights of at least 4.0 m, on average, once every 3.2 years (2.7–3.8). The BoB can expect peak reported winds of 62 m s−1 and surge heights of at least 8.0 m, on average, once every 115.4 years (55.8–381.1). In this ocean basin, surge heights are comparably higher when compared to other ocean basins. Application of the copula will mitigate future threats of storm surge impacts on coastal communities of the BoB.