High Precision Risk Assessment Of High-Temperature Heat Wave Disasters In South Asian Cities

In the context of global warming,frequent high temperature heat waves have gradually become one of the natural disasters that threaten human society and health.At present,domestic and foreign research on high-temperature heat wave risk assessment has made some progress,but mostly on large scale and large-scale space as the research object,and few studies have carried out high-precision high-temperature heat wave disaster risk assessment in a small area.The article takes Dhaka City as the research area,and uses meteorological statistics,demographics,and regional water system building data to build a relevant evaluation system,and uses chart statistical analysis methods,population spatialization methods,analytic hierarchy processes,and spatial overlay methods to obtain 30-meter resolution evaluation results of the high-temperature weather and heat wave time series characteristics analysis,high-temperature heat wave disaster risk evaluation,disaster vulnerability assessment,high-temperature disaster prevention and mitigation capability evaluation,and high-temperature heat wave disaster comprehensive risk evaluation.(1)The monthly maximum temperature and monthly high temperature days in the two 10-year periods from 1996 to 2005 and 2008 to 2017 show that the monthly maximum temperature reached the maximum in May or June before 2001.After 2001,it basically reached its maximum value in April or May.The highest temperature value also increased from about 38 ° C in the past to more than 40 ° C.The number of months with the highest temperature above 35 ° C also increased.The month with the earliest high-temperature days before 2001 was basically in April,and after 2001,high-temperature weather occurred in March,and the number of monthly high-temperature days also increased significantly.The proportion of months with high temperature days has increased from the past 50% to about 50% to 60%.In addition,the annual maximum temperature value,the annual maximum temperature average value,the annual total number of high-temperature days,the number of annual high-temperature heat waves,and the maximum number of days of continuous high-temperature indicate that the values of five high-temperature indicators in the second 10-year interval are much more than the value of the indicator in the 10-year interval.In general,Dhaka City entered the summer period earlier than before,and the temperature in summer was more severe than before.(2)According to the risk assessment results of the high-temperature heat wave disaster in Dhaka City,the southwestern city has the highest risk level.The main reason is that the denser population in the southwest produces more heat energy emissions and dense buildings,so the urban heat island effect is also more serious.According to the evaluation results of the vulnerability of the disaster-bearing body,the high-level areas of the vulnerability of the disaster-bearing body are mainly distributed in the southwest of the city.This is because a large number of people are distributed in the southwest of the city,resulting in high-temperature diseases and deaths during the summer heat.According to the evaluation results of the high-temperature heat wave disaster prevention and mitigation ability,the high-temperature heat wave disaster prevention and mitigation ability in the southwest of the city is strong.This is due to the large number of hospitals in the southwest region,so the distance between the region and the nearest hospital is smaller.According to the evaluation results of the high-temperature heat wave disaster risk level based on the evaluation results of hazards,vulnerabilities,and disaster prevention and mitigation capabilities,the proportion of regions with a higher or higher risk level in all administrative divisions of Dhaka City is over 50%,and it mainly distributed in the southwest region,the risk of high temperature disasters in the central and northeastern regions is low.