Temporal and Spatial Distribution of Short-time Heavy Rain of Sichuan Basin in Summer

Using rainfall dataset from 3079 observation stations in Sichuan from May to September during the period of2007 to 2012,and elevation data of 90 m resolution provided by SRTM(Shuttle Radar Topography Mission),the authors employed statistical analysis method to analyze the temporal and spatial distribution of short- time heavy rain(STHR) in summer. The results indicate that there are three high- incidence areas of STHR: Ya'an- Leshan- Meishan,Suining- Ziyang,and Mianyang- Guanyuan- Bazhong. The terrain of Sichuan basin is the major factor to effect the spatial and temporal distribution of STHR. The STHR mostly occurs in the late night to the morning(01 ~ 08). And STHR of different regions have their own diurnal variation characteristics. The duration and total precipitation of STHR in Sichuan basin separately concentrates in100 min and 40 mm. The median of 10- minutes heavy rainfall is 3mm,which can be used to distinguish between heavy precipitation processes and non- heavy ones. Precipitation rate of STHR in Sichuan basin is generally located at 3 ~ 6mm /10 min.The terrain has more influence on the extreme values of the precipitation rate than overall distribution.