1970～2012年青海湖流域冷暖季气温变化特征及突变分析

本文以线性倾向估计、累积距平、小波分析、Mann-Kendall检验及滑动t检验等方法对青海湖流域1970~2012冷、暖季及年均气温变化趋势、周期性和突变性进行分析.结果表明:(1)青海湖流域冷、暖季气温及年平均气温均呈显著增长趋势,其中,冷季增长幅度最大(0.45℃/10a),暖季增长最平缓(0.22℃/10a);从各站点的年、季气温变化来看,恰不恰地区增温幅度最大,刚察增幅最小.(2)冷、暖季气温及年均温的累积距平值绝大多数为负值,变化趋势相对一致,以1997年为转折点,1997年之前气候偏冷,之后趋于变暖.其中,年均气温变化幅度最小,冷季变化幅度最大.(3)冷、暖季和全年均存在较为复杂的周期性变化,其中,年平均气温在整个时间序列上存在4a和15a的周期,以15a最为显著;冷、暖季平均气温在短时间尺度上周期性不显著,主要为17a和27a的长时间尺度周期,以17a的变化周期最显著.(4)青海湖流域冷、暖季气温和年平均气温经检验均发生了突变,其中,年平均气温发生于90年代前期,冷、暖季均发生于90年代中期,且均于90年代末进入显著增温阶段.

Air Temperature Variation and Mutation Analysis of Cold/Warm Season in Qinghai Lake Watershed from 1970 to 2012

The trend ,periodicity and Mutation analysis of cold - warm seasonal and annual mean tem-peratures ,were analyzed in Qinghai lake watershed with methods of line analyze ,annual anomalies ,wave-let analyze ,Mann - Kendall and moving T test during the recent 43years .Some important results were ob-tained in four aspects as follows .（1）The cold - warm seasonal and annual average temperatures had the significant rising trends is increased in Qinghai lake watershed during 43years ,as the maximum ,the cold seasonal average trend is 0 .45 ℃ /10a ,while as the minimum ,the warm seasonal average trend is 0 .22 ℃ /10a ;In view of the spatial distribution pattern ,cold - warm seasonal and annual average temperature of the stations in Qinghai lake watershed all increase to different extent .The grow th of Qiabuqia is the maximum and that of Gangcha is the minimum .（2） The cumulative departure of average temperatures in cold - warm seasonal and annual are most of negative values .As a turning point ,the climate rushed into cold period be-fore 1997 ,after 1997 the climate rushed into warm period .The change of annual anomalies is the mini-mum ,while the change of clod seasonal anomalies is the maximum .（3） The time series of temperatures in cold - warm seasonal and annual all have the long cycles ,which contain some long and short ones .There are all obvious periodicity of 17 years and 27 years respectively for cold and warm seasonal mean tempera-tures .The time series of annual mean temperatures is complex and has cycles around 4 years ,15years and 30years .（4） The cold - warm seasonal and annual average temperatures in Qinghai lake watershed all had abrupt changes .The change years ,which happen in the earlier 1990s ,of annual average temperatures ,cold and warm seasonal average temperatures all happen in the middle of 1990s with methods of Mann - Kendall and Moving T test .The temperatures change from cold to hot in the later 1990s .