1971-2007年青藏高原南部气候变化特征分析

Analysis of the Climatic Change Characteristics in the Southern Tibetan Plateau from 1971 to 2007

利用我国青藏高原南部24个站点1971-2007年37 a的月平均气温和月降水量资料,对该地区气温和降水量的时空变化特征进行了详细分析.结果表明:1)37 a来该地区气候显著变暖,年平均气温升温率为0.33℃.(10a)-1,气候变暖主要发生于1990年后.1991-2007年气候变暖加速,升温率达到0.76℃.(10a)-1,1997年后升温尤为迅速,升温率达1.14℃.(10a)-1.变暖表现为全年温度升高,其中冬季增暖尤为显著,1971-2007年升温率为0.41℃.(10a)-1,1991-2007年快速上升为1.4℃.(10a)-1.变暖速率具有从东向西的增加趋势;2)年降水量呈增加趋势,但不明显.降水量变化地区差异显著,西部地区降水量显著减少,东部地区总体呈增加趋势.随海拔和地形升高,年降水量有从东向西的减少趋势;3)综合而言,37 a来青藏高原南部地区气候变化呈现暖湿组合特征,但地区差异显著,东部地区变暖变湿,西部地区在变暖变干.

Based on the monthly precipitation and monthly mean temperature data of 24 meteorological stations from 1971 to 2007 in the southern Tibetan Plateau,the spatial and temporal characteristics of climate variation are analyzed.The results show： 1） During 1971 to 2007,climate warming was significant in the southern Tibetan Plateau,with an increase rate of annual mean temperature by 0.33 ℃·（10a）-1,and the climate warming mostly occurred after 1990.Climate warming became faster during 1991~2007,with a rate of temperature rise of 0.76 ℃·（10a）-1;after 1997 climate warmed dramatically,with a rate of temperature rise of 1.14 ℃·（10a）-1.Climate warming was mainly characterized by temperature rise all year,especially in winter,with a rate of temperature rise by 0.41 ℃·（10a）-1 during 1991 to 2007.In the southern Tibetan Plateau,there was a significant spatial difference in temperature rise.The rate of the climate warming had an increasing trend from the east to the west.2） Over the period from 1971 to 2007,there was an unobvious increasing trend in annual precipitation in the southern Tibetan Plateau,with a significant regional difference（decrease in the western section whereas increase in the eastern section）.It seems that precipitation decreased from the east to the west with the increase of altitude and topography.3） In summary,over the period from 1971 to 2007,the climatic change in the southern Tibetan Plateau was mainly characterized by combination of warming and wetting,with a significant regional difference.In the eastern section,the climate shifted to warmer and wetter,whereas in the western section the climate shifted to warmer and dryer.