Spatial and Temporal Distribution Characteristics of Rainstorm and Flood Disasters Around Tarim Basin

The Tarim Basin is highly vulnerable to rainstorm and flood disasters, related to its special position of C-shaped terrain in the westerly belt and the ever-present monsoons. According to data of the storms and floods that occurred near the Tarim Basin from 1980 to 2019, the proportional weight method was used to construct the disaster exponent; whereas, the percentile method was used for classification. As a result, the disaster level is divided into four grades: mild, moderate, severe, and extremely severe. The results also indicated a phenomenon: the geographical frequency distribution of rainstorm and flood disasters around the basin shows more occurrences in the west and north, and less in the east and south, and occur mainly from April to September (in spring and summer); and June and July are the high incidence periods. The annual frequency of rainstorm and flood disasters around the basin showed a significant linear growth trend from1980 to 2019, that is, an increase of 8.6 times every 10 years. However, the annual disaster exponent changed abruptly in 1985 and 1999, when the average values of the disaster exponent in 1980-1985, 1986-1999 and 2000-2019 were7.63, 64.66 and 25.80, respectively. The contribution rates of annual occurrence times of disasters with Grades 1 to 4 to damage exponent are 4%, 2%, 24% and 70%. In conclusion, to better mitigate rainstorm and flood disasters in the basin, focus of optimal prevention should occur Grade 3 and Grade 4 rainstorm and flood disasters.