西藏地区50年气候变化特征

Characteristics of climatic variation in Tibet area for last 52 years

基于西藏38个气象站1955-2007年的月降水和平均气温资料,对年、四季的气温和降水的变化趋势进行了分析,并对逐季的变化趋势进行了显著性检验。线性倾向估计表明:四季和年的平均气温、平均最高气温、平均最低气温具有显著增温趋势,特别是平均最低气温尤其显著。四季和年的降雨量均有增加趋势。Mann-Kendall检验表明:20世纪80年代,四季和年的气温先后发生了突变,80年代中期增暖趋势显著。20世纪60年代末冬、春、秋季降水量发生突变,1970年附近之后冬、春、秋季降水量存在显著增加趋势。

Based on the data of temperature and precipitation of 38 stations in Tibet from 1955 to 2007,the seasonal variation trends and their seasonal differences of temperature and precipitation were analyzed,and significance test also was carried out.The linear trend estimation indicates that annual mean temperature,minimum and maximum temperature had an evident warming trend,especially the mean minimum air temperature.Annual mean precipitation,minimum and maximum precipitation had an increase trend.Mann-Kendall analysis shows that from the end of 1980＇s,annual mean and seasons air temperature appeared to be a transition,the warming was more evident since the middle of 1980＇s.From the end of 1960＇s,winter,spring and summer precipitation appeared to be a transition,precipitation increase was more evident since 1970.