Analysis of rainfall intensity characteristics of precipitation events causing rainstorm and flood disaster in flood season in Inner Mongolia

Based on 108 precipitation events caused by heavy rain and flood disaster (DPE) from 2017 to 2018 during flood season (from June to August)in Inner Mongolia, the characteristics about duration, maximum value and diurnal variation of the precipitation intensity were analyzed, and DPE threshold was determined by double e-exponential function and percentage method. The results show that: (1) There is an area with high incidence of DPE in the east of the Greater Khingan Mountains. It can occur up to five or six times, and the longest duration is close to 10 days. The second highest incidence area of DPE occurs in the south of Yinshan Mountain.(2) The maximum and minimum value of precipitation intensity of DPE appear in eastern regions and the maximum range reaching 70.4 mm·h^-1. The maximum value of precipitation intensity in the western and central regions is close, while the minimum range of precipitation intensity in the central region is 16.0 mm·h^-1. While the maximum value of average precipitation intensity of DPE happen in western regions, the minimum value is in the central regions.(3) The diurnal variation characteristics of precipitation intensity of DPE have regional differences. Especially, the characteristics of the occurrence time about the maximum value of precipitation intensity (average precipitation intensity) are dispersion, non-concentration and great difference in the western regions. It tends to appear in the early morning, morning, noon and evening. But in other regions it tends to occur at noon and afternoon; (4) The thresholds of DPE in western, central and eastern regions are 13.8mm·h^-1, 10.0mm·h^-1 and 14.2mm·h^-1, respectively.