Study on Estimation of Regional Evapotranspiration by Remote Sensing in the Mu Us Sandland——A Case Study of Wushen County in Inner Mongolia
毛乌素沙地蒸散量的遥感研究——以内蒙古乌审旗为例

Accurate estimation of surface evaporatranspiration(ET) is important in the study of global climatic change,scientific management of water resources.In this paper,the evapotranspiration from 1981 to 2003 in Wushen County,located in the Mu Us Sandland,was estimated by using Advection-Aridity Model based on the complementary relationship hypothesis with 1km resolution reflectance data of NOAA/AVHRR and MODIS and meteorology data.The temporal and spatial distribution of ET was analyzed.The results showed:(1) The annual average of ET of Wushen County is 252 mm.Spatially,it increases from northwest to southeast.The multi-year relative variation of ET in Wushen County is from 10% to 24%,larger in northwestern and southeastern parts and smaller in eastern and southern places.Seen from the yearly spatial distribution of the ET,there is the same trend that ET increases from west to east.(2) Ordered in land cover and land use in 2002,ET decreases in following sequence: water body,crop field,grassland,shrub,forestland and sand land.(3) Interannual change of ET in Wushen County is large while the maximum value is up to 300mm and the minimum value is only 200 mm.The monthly distribution of ET takes a 'bell' shape,with peak in about July to September.