Research On Improvement Of Hazard Indicator Of Typhoon Rainstorm Based On Satellite Data

The hazard indicators of typhoon rainstorm are directly related to prediction,prevention and mitigation work of typhoon rainstorm flood,and related research is of great significance.At present,the research on typhoon rainstorm flood disaster indicator pays little attention to the typhoon precipitation separation.Also,the optimization of high-precision disaster indicators that matched with high spatial-temporal resolution satellite data is insufficient.And indicators need to consider the rainfall intensity,and the intensity of the rainstorm disaster factors,such as the duration of the rainstorm,the verification calculation of the results of the typhoon rain flood algorithm.In previous studies,the spatial distribution of precipitation was mostly based on precipitation data from meteorological stations,or spatialized by interpolation methods.Recently,fusion satellite precipitation products have developed rapidly,which can effectively utilize the respective advantages of multiple precipitation data sources,and are more reasonable in terms of precipitation temporal and spatial distribution.And,prerequisite for typhoon rainstorm flood study is to separate the typhoon precipitation from the overall precipitation,because of the typhoon influence limiting.Standardized and programmed identifying for typhoon precipitation have matured objective methods.Due to typhoon long-distance precipitation,this research believes that typhoon precipitation is possible within a range of about 1 100 km away from the typhoon center(that is,the upper limit of the radius of the typhoon peripheral flow system).Then it is necessary to use the typhoon rainstorm flood algorithm to delimit the flood disaster distribution area based on the typhoon precipitation data.At present,a large number of studies are still using the Meteorological Bureau's precipitation indicator(50 mm/day),and this is likely to affect the accuracy of the delineation.Short-term rainstorms need to comprehensively consider the lasting time,process and hourly intensity of rainstorm to analyze the spatial and temporal distribution characteristics of rainstorms.Finally,from the difference between the disaster-causing distribution area delineated by the algorithm and the actual disaster-affected area,the characteristic points of different typhoon rainstorm flood algorithms can be studied.Based on the above situation,this paper proposes the improvement of the typhoon rainstorm index based on satellite data.First,using the China Meteorological Station and the CMORPH data set,according to the typhoon precipitation separation method,the typhoon hourly precipitation data is obtained.Secondly,combined with the actual flood disaster data,the advantages and disadvantages of the typhoon rainstorm algorithm based on the daily precipitation index(D-TRF)and the typhoon rainstorm improved algorithm based on the hourly rain intensity index(H-TRF)are compared.Finally,the author proposes the improvement direction of the typhoon rainstorm flood index based on satellite rainfall data.This paper draws the following conclusions:(1)According to the typhoon precipitation separation,the overall effect of typhoon precipitation separation is better,but it depends to a large extent on the setting of parameters.The parameter adjustment method can be gradually developed in the future.Based on the satellite precipitation data,the typhoon precipitation separation can be used to obtain more accurate and reasonable typhoon precipitation,which is more conducive to the study of typhoon rain disasters.(2)Obtain typhoon precipitation based on satellite precipitation data,and then according to D-TRF and H-TRF respectively,it is concluded that the flood disaster area delineated by H-TRF is more closely related to the actual disaster situation,which can improve the disaster indicator caused by typhoon rain.(3)The relationship between the percentile of the rain intensity index and the actual disaster data is discussed,and the different characteristics of the rain intensity index are obtained.In the subsequent research,a comprehensive analysis of precipitation and rain intensity index can be considered,and the two can be organically combined.