近40年西昌北郊降水变化分析

Analysis of Precipitation Change in North Xichang in Recent 40 Years

利用西昌市北郊某观测站1974~2009年近40年的逐日降水资料,采用通用的极端气候指数,逐年统计各级降水的发生日数资料。采用气候趋势分析法、滑动平均法、多项式拟合法及Morlet小波变换等方法诊断分析各类降水事件的气候变化特征。结果表明：雨日、冰雹的减少趋势显著;总降水量、年最大日降水量、强降水日数R95%、中等雨日数R75%、雨季总降水量呈上升趋势,但并不显著,降雪日数的下降趋势也不显著;暴雨日数的长期变化趋势不明显;各类降水事件及极端天气存在一定的振荡周期。针对现阶段气候变化特点,提出了应对建议。

Based on the daily precipitation data of north Xichang from 1974 to 2009,annual days of levels precipitation data are analyzed by current extreme climate index.And then the variation characters of precipitation events are diagnosed using the least squares method,moving average method,polynomial fitting method and Morlet Wavelet method.The results show that annual days of rain date and hail decreased significantly.Total precipitation,annual maximum daily precipitation,heavy precipitation days R95%,moderate precipitation days R75%,and total precipitation during the rainy season are rising,but not significantly.The downward trend of snow days is not significant,too.rainstorm days in long-term trend is not obvious.There are certain types of precipitation events or extreme weather oscillation cycle.For climate change at this stage,we proposed deal recommendations.