【摘要】 利用遥感反演干旱区大面积区域的蒸散量,对于该区域水资源的有效利用具有重要的指导意义。以鄂尔多斯高原皇甫川流域为研究区,利用遥感方法对1996年、2003年和2007年3期影像数据进行处理,基于地表能量平衡原理,结合同期气象资料,估算出流域日蒸散量,发现反演得到的日蒸散量分布与地表状况比较吻合,植被覆盖区日蒸散量较裸地区的日蒸散量大,植被密集的地方蒸散值较大,且明显高于植被稀疏的地区,阳坡的蒸散量明显高于阴坡,日蒸散量最大的对应于水体,最小的为裸地。运用实测数据和FAO推荐式进行了局部验证,证明该遥感方法具有一定的适用性。并对反演的3期蒸散量结果进行了对比分析,发现从1996年到2003年和2007年,8月份流域日蒸散量呈逐年递减的趋势。更多还原

【Abstract】 Using remote sensing approach for retrieval of large area evapotranspiration has important guidance for effective utilization of water resources.The Huangfuchuan watershed located in Ordos Plateau which has been intensively studied in the past was taken as the study area.Remote sensing approach was used to retrieve instantaneous evapotranspiration based on the estimation of land surface characteristics and fluxes from Landsat-5 TM images collected in 1996,2003,and 2007,and using auxiliary environmental data from the same time periods.Daily evapotranspiration was estimated by scaling.The result of evapotranspiration distribution was consistent with land surface conditions.The daily evapotranspiration of area covered by vegetation was higher than bare land.The daily evapotranspiration of dense vegetation was higher than the sparse.The daily evapotranspiration in sunny slope was higher than that in shady slope.The maximum daily evapotranspiration was water body and the minimum one was bareland.Results for 1996 and 2007 were verified by using measured data and the FAO method.This level of uncertainty was acceptable;therefore,the method was applicable.These three images were compared and evapotranspiration decreased from 1996 to 2003 and 2007.更多还原