近40年洮河流域干燥度变化趋势分析

Trend analysis for the variety of arid index in Taohe River Basin in recent 40 years

利用洮河流域7个气象站1971-2010年的地面气象观测资料，根据Holdridge生命地带模型对洮河流域近40 a的干燥度变化进行了分析。结果表明：近40 a洮河流域内可能蒸散率（PER）以0．02·10a-1～0．07·10a-1的趋势上升，20世纪90年代后 PER的平均值比20世纪90年代前上升了0．12，洮河流域从20世纪90年代开始出现了明显的变干的趋势；近40 a洮河流域温度呈明显上升趋势，上升趋势为0．32～0．54℃·10a-1，20世纪80年代末到90年代洮河流域气温出现了暖突变；降水量呈减少的趋势，其中以中、下游减少最明显，减少趋势为13．3～21．8 mm·10a-1；洮河流域出现了明显的暖干化趋势。

Using the surface meteorological observed data in 7 climate stations in Taohe River Basin,according to the Holdridge life zone model analyzed the variety of arid index in Taohe River Basin in recent 40 years（1971~2010）. The results shown that：The possible evapotranspiration rate （PER）was increasing by the tendency of 0 .02 to 0 .07· 10a-1 in Taohe River Basin in recent 40 years,the mean PER was increased 0 .12 after the 1990s comparing before 1990s .From starting 90th 20 century,the Taohe River Basin occured obvous drying trend,the temperature showed an obviously increasing trend with the tendency ratio of 0 .32℃·10a-1 to 0 .54℃·10a-1 .The warm mutation of the temper-ature was occured in the end of 1980s to 1990s,the precipitation in the Taohe River Basin was shown a decreasing trend . Among them,the middle reaches and lower reaches was reduced most obvious,the decreasing trend was 13 .3 to 21 .8 mm·10a-1 .In the Taohe River Basin occurs a obviously warm-drying trend .