气候变化对西藏雅鲁藏布江中游地区潜在蒸散量的影响分析

Impact Analysis of Climate Change on Potential Evapotranspiration over Midstream of Yarlung Zangbo River in Tibetan Plateau

本文利用西藏雅江中游地区1961～2009年逐日气象资料和Penman–Monteith公式,计算并分析了PE(潜在蒸散量)的时空分布特征,运用多元回归方法定量计算各气候因子变化对PE变化的贡献率。研究表明:近49年来,拉萨年潜在蒸散量呈明显增加趋势,增幅为8.21mm/10a,日喀则和江孜呈不显著的减少趋势,而泽当减少趋势显著,减幅最大达-24.71mm/10a。PE变化趋势的季节差异较大,年潜在蒸散量在1993年发生突变,在全球气候变暖的背景下,平均风速明显减少从气候因子角度解释了潜在蒸散减少的原因。

Based on daily meteorological data form 1961 to 2009 over Midsteam of Yarlung Zangbo River in Tibetan Plateau,Using Penman –Monteith method,The temporal and spatial distribution characteristics of PE（potential evapotranspiration）was calculated and analyzed in this paper.And using Multiple Regression,The Contribution rate to PE variations by climate factors was also calculated quantitatively.The reaserch shows that：In the recent 49 years,The PE of LhaSa showed a trend of increasing obviously,The growing rate reached 8.21mm/10a,Shigatse and Gyantse has been decreased not obviously,but Tsedang decreased obviously,The reduction reached-24.71mm/10a.The variation trend of PE has a big seasonal difference,an abrupt time is in 1993.In the background of global warming,The significant reduction of average wind speed has explained the cause of reduction of PE from the climate point of view.