Based on the monthly meteorological data of 31 sites in Yunnan Province,we analyzed variation in drought temporal characteristics and the spatial distribution and frequency of drought based on percentage of precipitation anomalies (Pa) and potential evapotranspiration (ET0) index.The results showed that:from 1958 to 2004,there were drought in spring,summer,autumn and winter in Yunnan Province,among them,the winter drought was the most serious,followed by spring,and then autumn,and only two years of summer occurred drought,and the rest of the years did not occurred drought in summer;In spatial distribution,central Yunnan and Southeast Yunnan were relatively dry.The southwestern Yunnan,especially the Diqing area which bordered with Tibet,the drought was very serious;the total precipitation in Yunnan Province was abundant,but the spatial distribution of precipitation and the over-concentration of precipitation in time were the main reasons leading to the occurrence of drought in Yunnan Province.%基于云南省31个站点47年的逐月观测气象数据,通过计算降水量距平百分率(Pa)及潜在蒸散量(ET0)指数值,从时间和空间2方面对干旱发生频率及发生地点进行分析.结果表明:1958-2004年,云南省春、夏、秋、冬4个季节均有发生干旱的情况.其中,冬季干旱最为严重,春季次之,而夏季仅有2年发生了轻微干旱,其余年份夏季无旱.空间分布上,滇中与滇东南地区相对较旱;滇西南降水充沛,极少干旱;滇北,尤其是与西藏接壤的迪庆地区旱情较为严重.云南省总体降水量充沛,但降水在空间上分布不均和降水在时间上过于集中是导致干旱事件发生的重要原因.
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