Risk Assessment Of Tropical Cyclone Disaster In Bangladesh

Tropical cyclone is a very destructive weather system which often accompanied by strong winds,rainstorms and storm surges.It's prone to initiate secondary disasters such as floods,landslides and mudslides.Bangladesh is at the apex of the Bay of Bengal and has long coastline.Most of the land of Bangladesh is alluvial plains with the average elevation only 1 to 1.5 meters.And it has an intensive river network as well as the high population density,the backward economic condition.All of these factors make Bangladesh as one of the world's worst countries affected by the tropical cyclone.This paper focuses on the tropical cyclone disaster in Bangladesh.The temporal and spatial distribution characteristics of tropical cyclones landing in Bangladesh during the year from 1980 to 2015 are analyzed.By establishing a risk assessment system and using the established evaluation model,this paper makes a dynamic assessment of the comprehensive risk of November 15,2007 and November 16 during the process of tropical cyclone “Sidr” landed in Bangladesh.The main conclusions are as follows:(1)The interannual variation,seasonal variation,landing path,initial position,duration and intensity of tropical cyclones which landed in Bangladesh from 1980 to2015 are analyzed.It is found that almost every year has at least one tropical cyclone landed in Bangladesh,and it mainly generates in May or October on the north Indian Ocean and Bengal Bay.The tracks of landing tropical cyclones are dominated from southwest then to northeast.The primary area of the original cyclones' genesis position is in the south of 15 ° N and east of 90 ° E.About 40% of the tropical cyclones has reached the scales of very severe or higher cyclonic storm.(2)The dynamic risk assessment of tropical cyclone "Sidr" which landed in Bangladesh on the day of November 15,2007 and November 16 is evaluated.The results show that the tropical cyclone "Sidr" mainly affected the southern Bangladesh,especially the Barisal area,the southern Khulna,the northwest area of Chittagong and the southern part of Dhaka.Compared with the comprehensive risk assessment results of the day of November 15 and November 16,it can be seen that the high risk areas of November 16 is also the ones of November 15.These areas are likely to suffer heavy losses.(3)The results of the comprehensive risk assessment are verified by the post disaster survey data.The results show that the two affected areas are approximately the same.The affected population is in line with the assessment results of November15.This is because the influence of tropical cyclone "Sidr" on Bangladesh is mainly due to the strong winds and heavy rains during its landing on November 15.The number of deaths is consistent with the assessment results of November 16.This is because the continuous rainfall and strong winds aggravate the disaster,which makes the high risk area of November 16 become the worst-hit areas which affected by tropical cyclone "Sidr".