中文摘要：

基于Budyko水热耦合平衡假设,推导了年径流变化的计算公式,分析了长江流域多年平均潜在蒸发量、降水量、干旱指数和敏感性参数的空间变化规律。选用BCC-CSM1-1全球气候模式和RCP4.5排放情景,把未来气候要素预估值与LS-SVM统计降尺度方法相耦合,预测长江流域未来的气温、降水和径流变化情况。采用乌江和汉江流域的长期径流观测资料,分析验证了基于Budyko公式计算年径流变化的可靠性。结果表明：降水量变化是影响径流量变化的主导因素;长江各子流域未来径流相对变化增减不一,最大变幅10%左右;在未来2020s（2010—2039年）、2050s（2040—2069年）和2080s（2070—2099年）3个时期内,长江南北两岸流域的径流将出现＂南减北增＂现象,北岸径流变化增幅逐渐升高,南岸径流变化减幅逐渐降低。

英文摘要：

The calculation formula of annual runoff change was derived based on Budyko hypothesis. The spatial distribution laws of annual mean potential evapotranspiration,precipitation,and aridity index as well as sensitivity coefficient over Yangtze River basin were analyzed. The outputs of global climate model BCC-CSM1-1under RCP4. 5 emission scenario was combined with LS-SVM statistical downscaling method to predict future temperature,precipitation and runoff changes in Yangtze River sub-basins. The observed hydrological data series of Wujiang and Hanjiang subbasins were used to verify Budyko formula for estimating relative runoff change. The results show that precipitation is a dominant factor affecting runoff change; the relative runoff change values are different in each sub-basin and the largest change value is around 10%; The relative runoff changes increase in the north bank and decrease in the south bank of Yangtze River basin during three future periods,i. e.,2020s（ 2010—2039）,2050s（ 2040—2069） and2080s（ 2070—2099）. The proposed methodology provides a new approach for runoff prediction in large scale basin and un-gauged region.