Temporal and spatial distribution of different short-time rainstorm in Fujian

By using rainfall dataset from 20 observation stations in Fujian during 1963-2012, the temporal and spatial distribution characteristics of frequency of storms with precipitation intensity reaching rainstorm and severe rainstorm within short-time (1 h,3 h,6 h) and 24 h ,as well as the spatial distribution of extreme value of rainstorms, were analyzed. The results show that for rainstorms, the spatial distribution characteristics of rainfall frequency is basically the same for different time scales, with three high-incidence regions, respectively located in the south of Zhangzhou to south-west of Longyan, northeast of Ningde coast and north-west of Nanping. For severe rainstorms, over 6 h time,the high-incidence regions are in the coastal, and inland occurs less frequently. Analysis of decadal trend shows that 1 h to 6 h time rainstorms mainly have natural changes, or increased slightly. The increasing trend for 24 h long time rainstorms is more evident than that of short duration storms. For severe rainstorms, in most stations the increasing trend of 1 h to 3 h time is more significant than 6 h. The monthly distribution characteristics of rainstorms inland appears unimodal, with the peak in June. The frequency of rainstorm over 6 h time is the largest for a year. While in the coastal it shows bimodal distribution; the peaks are in June and August. The frequency of rainstorm is the largest for 1 h and 3 h time in rainy season, and for 6 h and 24 h time in summer.