四川区域暴雨过程中短时强降水时空分布特征

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

  • 摘要: 利用2007~2012年5~9月四川省3079个观测站的分钟级降水资料,并结合SRTM (Shuttle Radar Topography Mission)提供的分辨率为90m的地形高程数据,采用统计分析方法,分析了四川省区域暴雨过程中短时强降水的时空分布特征。结果表明:(1)四川省区域暴雨过程中短时强降水主要出现在盆地的三个区域:雅安-乐山-眉山地区、遂宁-资阳地区、绵阳-广元-巴中地区。(2)强降水过程主要发生在后半夜到凌晨(01~08时),不同区域的强降水过程具有各自明显的日变化特征。(3)可以用3mm/10min的标准线来区分四川盆地强降水过程与非强降水过程。短时强降水过程降水率一般为3~6mm/10min,地形对短时强降水率的整体分布影响不大,但是对降水率的极端值影响较大。

     

    Abstract: 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.

     

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