近50年河西走廊地区降水均值突变特征分析

Analysis on Mean Abrupt Change of Precipitation in Hexi Corridor Region in Recent 50 Years

利用1960-2009年河西走廊地区16个测站的年和季降水资料,在对该区降水量进行气候分区的基础上,采用墨西哥帽小波函数,对该区域各代表站年和季降水的均值突变特征进行了小波分析,揭示了河西走廊地区降水变化的多时间尺度突变特征。结果表明,河西走廊地区降水量在1968,1973,1982,1991及2005年左右发生了均值突变,其中,河西走廊西部荒漠区(敦煌)降水量在1968年发生了由偏少到偏多的极强突变,在1982-1983年间发生了由偏多到偏少的强突变,在1991年发生了由偏少到偏多的较强突变,2007年发生了由偏多到偏少的较强突变;河西走廊东部(武威)年降水量在1973年和1989-1992年间分别发生了由偏多到偏少和由偏少到偏多的较强突变;中部(张掖)年降水量在2004-2005年间发生了由偏少到偏多的强突变;马鬃山区(马鬃山)年降水量在1968年发生了由偏少到偏多的较强突变,1982年发生了由偏多到偏少的强突变;各站夏季降水量占年降水量的50%以上,夏季降水量突变特征最显著,其显著突变年与年降水量的显著突变年具有较好的一致性。

Based on the precipitation data at 16 meteorological stations in Hexi corridor from 1960 to 2009,the multi-scale mean abrupt changes of annual and seasonal precipitation at each typical station in recent 50 years had been analyzed based on the Mexican Hat wavelet technique.It was showed that mean abrupt changes of annual precipitation in Hexi corridor were detected in 1968,1973,and around 1982,1991 and 2005.Abrupt changes of precipitation from less to more were detected in 1968 and 1991 in the western corridor（Dunhuang）.Abrupt changes of precipitation from more to less occurred around 1982 to 1983 and in 2007.The abrupt change in 1968 was the most significant one.In the eastern Corridor（Wuwei）,there were abrupt changes from more to less in 1973 and from less to more around 1989-1992,respectively.In the middle Corridor（Zhangye）,there was abrupt changes around 2004-2005 form less to more.And in the Mazhongshan region（Mazhongshan）,there were abrupt changes from less to more in 1968,and from more to less in 1982.Summer precipitation at each station accounted for more than 50% of annual precipitation.And among four seasons,the abrupt changes were the most significant ones,which also consistent well with annual precipitation.