干旱区区域蒸散发量遥感反演研究

Regional evapotranspiration retrieval in arid areas

为研究干旱半干旱区蒸散发量,以新疆为研究区域,基于地表能量平衡,依据地表温度与反照率关系确定蒸发比,利用MODIS影像遥感估算新疆地区的蒸散发量。通过野外验证,模拟蒸散量与涡度相关仪野外观测量一致,平均误差在0.40mm/d。在干旱区,蒸散发量与降水的相关性在82%,与气温的相关性分别为46%。通过模型反演,2005年研究区在空间上以裸土蒸发为主,蒸发量在0-2mm/d之间,主要在塔里木盆地、准噶尔盆地和吐鲁番盆地,而蒸散发量较高地区主要为天山山脉下垫面为林地草地和平原绿洲农田区域,蒸散发量最大达6mm/d。

Xinjiang is a typical arid area in China.The objective of this research is to present a description of a method based on the energy balance and evaporative fraction,which is obtained by broadband albedo and land surface temperature,to estimate evapotranspiration（ET） in arid areas based on MODIS images.In the validation,the simulated ET is as same as the measured ET by eddy covariance tower site and the mean difference is 0.40mm.In arid areas,the correlation between evapotranspiration and precipitation is of 82%,and the correlation with the temperature is of 46%.The ET always fluctuated from 0 to 2mm in the most part of region in 2005,especially the Tarim,Junggar and Turpan basins.In the mountain area,especially Tian-shan mountain and crop land of oasis,the ET values is upto 6mm.