内蒙古地区极端降水事件分布特征

基于内蒙古地区94个气象站1961—2007年逐日降水量资料,利用累积频率法,分析了极端降水事件变化特征。结果表明：（1）近50年内蒙古地区极端降水事件和极端强降水事件发生的强度和出现的频次均呈现出增多趋势,尤其在1977年降水发生突变之后,增加趋势更为明显。（2）近50年内蒙古地区最长连续无降水日数和最长连续降水日数持续时间缩短,表明连续性干旱和降水的持续性减弱,尤其是进入本世纪后,最长连续无降水日数陡升和最长连续降水日数陡降,气候湿润程度下降,加之全球气候变暖,使内蒙古地区进入本世纪后暖而干的气候特征更为明显,这对农牧业生产和生态环境保护极为不利。（3）内蒙古地区近50年小雨和暴雨日数的减少,降水强度的加大,使全区降水不稳定性增加,降水有极端化发展趋势,尤其是在1987年气温发生突变之后,降水强度变化更大。

The Distribution Characteristics of Extreme Precipitation Events in Inner Mongolia

Based on the daily precipitation data of 94 weather stations in Inner Mongolia during the period of 1961—2007,by means of cumulative frequency method,the distribution characteristics of extreme precipitation events in Inner Mongolia was analyzed.The results shows that the intensity and frequency of extreme precipitation events and extreme strong precipitation events present increased tendency in Inner Mongolia in recent 50 years,the increased tendency of extreme precipitation events is more obviously especially after the precipitation mutation in 1977.The longest and durative days of precipitation and no precipitation are turning short in recent 50 years,indicates the continued drought and durative precipitation weaken,especially in 21st Century the longest and durative no precipitation days are sharp ascending and the longest and durative precipitation days are sharp descending,the moisture index is descending,under the background of global warming,the warm and dry climate characteristic is very obvious in Inner Mongolia,it will be most disadvantageous for the production of agriculture and animal husbandry and ecological environment protection.The light rain days and heavy rain days are reduced in Inner Mongolia in recent 50 years,precipitation intensity are increased,it leads precipitation instability increase,the precipitation has a extreme development tendency,the variety of precipitation intensity is more exquisite especially after the temperature mutation in 1987.