Analysis on Temporal and Spatial Distribution Characteristics of Strong Hour Rainfall Intensity in Sichuan during 2008-2012
Based on the hourly precipitation data of 1052 stations during 2008-2012 in Sichuan Province, multiple-time-scale variations of the frequency and the extreme rainfall intensity of strong hour rainfall intensity (hereafter SHRI) are investigated by using statistical diagnostic methods.And get the following main conclusions.(1) The frequency of SHRI which is more than 20 mm · h-1 reached 3537.8 times annually.Averagely the extreme rainfall intensity is more than 100 mm · h-1 per year, and it jumped in 2012.(2) The SHRI area mainly concentrated in most parts of the whole basin and the Southwest of Panxi area, and the strong precipitation with high centers are mainly located in the longitudinal steep terrain area from basin to mountain transition.The extreme rainfall intensity area also concentrated in most parts of basin and Panxi area which is more than 30 mm · h-1.Obviously there is a very close contact between rainfall frequency, extreme rainfall intensity and altitude.The windward slope of the steep terrain weakened the reduce rate of frequency and extreme rainfall intensity with higher elevation.(3) Monthly changes of frequency are more significant than monthly changes of extreme rainfall intensity.SHRI occurs most frequently in July, followed by August, at least in May.The extreme rainfall intensity is more than 100 mm · h-1 from June to September.(4) The diurnal variations of SHRI which beyond 20 mm · h-1 and 30 mm · h-1 show a single active peak during night, but the diurnal variations of SHRI which beyond 50 mm · h-1 has multiple peaks, and it happens very suddenly.Diurnal variations and active peaks also have great differences in different areas of basin.
NETL
NSTL
万方数据
维普
