Temporal and Spatial Distribution Characteristics of Torrential Flooding Disasters with Different Intensities in Tarim Basin

Abstract

As torrential flooding often cause huge economic losses and casualties, analyzing the spatio-temporal variation characteristics of torrential flooding events is of great significance to disaster prevention and reduction. Based on five indicators for torrential floodingin the Tarim Basin in 1990-2019, ratio weighting and non-dimensional linear summation were employed to calculate disastrous loss indicators that represent disaster intensity. Afterwards, percentile method was used to divide disasters into four levels, i.e., general, relatively severe, severe and extremely severe. The results showed that the regions where Level-1 to Level-4 disasters frequently and recurrently occur are concentrated in Kizilsu Kirghiz Autonomous Prefecture, Aksu Prefecture and Kashgar Prefecture and that such disasters often take place from April to July. The interannual variation of the frequency and intensity of Level-1 disasters presented a linear upward trend, and the frequency and disastrous loss indicator increased by 14.6 and 0.8 per 10a, respectively. The interannual variation of the frequency and intensity of Level-2 to Level-4 disasters did not show a linear increase or decrease trend. The threshold for 12-hour precipitation that may cause torrential flooding in the basin from March and October is 10mm. The annual frequency of 12-hour precipitation exceeding the threshold increased year by year, so did the frequency and intensity of Level-1 disasters.