中文摘要：

基于参照干湿限的遥感蒸散发模型（REDRAW）反演了黄河中游河龙区间5个典型子流域2000—2010年的蒸散发,结合归一化植被指数（NDVI）分析了区域蒸散发的年内和年际特征。年尺度流域水量闭合验证结果表明,REDRAW模型反演的区域年蒸散发多年平均为358.3 mm,接近降雨径流之差351.4 mm,平均相对误差2.6%,年尺度ET反演结果较为合理,说明REDRAW在研究区域具有一定的适用性。区域蒸散发与NDVI年内变化较为一致,年际变化存在一定正相关,11年间增长趋势较为明显。区域NDVI的显著增加与植树造林等水保措施有关,结合流域的降雨径流等水文数据分析可知,植被覆盖的增加一方面增加蒸散发耗散,另一方面通过截留等作用促使径流减少。

英文摘要：

The evapotranspiration （ET） for the five typical sub-basins of Hekou -Longmen Section in the middle Yellow River during the period of 2000-2010 is estimated with REDRAW model. Combined with NDVI data, the annual and inter-annual variation of ET is analysed. Annual water balance validation shows that the average annual ET from REDRAW is 358.3 ram, approximating the difference of precipitation and runoff （351.4 ram） with the mean relative error of 2.6%. Therefore, REDRAW is capable of simulating rea- sonable ET in the study area. The variation of ET during the year is in accordance with that of NDVI. A positive correlation existed between yearly ET and NDVI, and both of them increased notably during the 11 years. The constant growth of NDVI is probably caused by the water-and-soil conservation measures. Analysis referring to other hydrological data in terms of precipitation and runoff indicates that the increase of vegetation cover may promote ET, as well as reduce runoff through interception.