四川盆地地处中国西南地区，其气候湿润，地势多变，是中国五大的粮食产业基地之一。通过标准化降水指数法对逐日降水量进行处理发现，50年间盆地夏季期间极端干旱频次呈上涨趋势，空间分布呈现出由局部向整体蔓延的势态；而极端洪涝发生频次基本保持不变，分布基本覆盖整个盆地地区，但是近些年发生强度大幅增加，盆地东部洪涝存在明显20年周期。%Sichuan basin is located in the southwest of China, its climate is humid , and its terrain is changeful. Also it is the one of the biggest food production in China. By sorting and calculation of precipitation, we found the extreme drought rate rose fast during the last 50a. The spatial dis⁃tribution presents by the local trend of spreading to the whole. Starting from the 70 s the extreme drought happensin the eastern basin. and extreme flood frequency remains the same. Its flood basical y covers the whole basin area,but the flood in the eastern basin is in 20-year cycle.
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