中文摘要：

采用经过参数率定的区域蒸散互补关系原理AA模型和全球海气耦合模式ECHAM5/MPI-OM估算长江流域1961-2007年的实际蒸发量,运用线性回归法和非参数Mann-Kendall秩次相关检验法对2种方法估算的实际蒸发量进行年、年代际和季节变化特征分析与对比,揭示长江流域实际蒸发量的变化规律。结果表明：长江流域年实际蒸发量呈现显著的下降趋势,2种方法估算的结果分别以-9.3mm/10a和-3.6mm/10a的速度下降,从20世纪90年代开始实际蒸发量的下降幅度明显增大;在季节变化上,2种方法估算的结果在春、秋季均呈现显著的下降趋势,在夏、冬季表现为相反的变化趋势;在空间差异上,流域各地区的变化趋势总体较一致,其中以中下游地区的变化趋势最为显著。

英文摘要：

In this paper,the actual evapotranspiration in the Yangtze River Basin is calculated by the advection-aridity（AA） model with parameters validation during 1961-2007 and simulated by the general circulation model（ECHAM5/MPI-OM） from 1961 to 2000.The linear regression method and nonparametric Mann-Kendall test are used to examine the trends of annual,inter-decadal and seasonal estimated actual evapotranspiration.The results show that the annual actual evapotanspiration estimated by the above two methods presents the same decreasing trends in the upper and the mid-lower reaches of the Yangtze River,and this decrease is more significant in the mid-lower than in the upper Yangtze.The significance of decreasing annual actual evapotranspiration calculated by AA model is higher than that simulated by ECHAM5/MPI-OM,and the decreasing rate is about-9.3 mm/10a and-3.6 mm/10a respectively.The former is attributed to the significant decreasing trend in summer actual evapotranspiration,while the latter is caused by a significant decreasing trend in autumn and spring actual evapotranspiration.In the mid-lower Yangtze River,the seasonal actual evapotranspiration estimated by the two methods displays consistent changing trends,i.e.decreasing actual evapotranspiration in spring,summer,autumn,and increasing in winter.In the upper Yangtze River,the seasonal actual evapotranspiration estimated by the two methods shows similar downward trends in spring and autumn;the summer and winter actual evapotranpiration estimated by the two methods shows upward changing trends.