Estimation of Regional Evapotranspiration in the Mu

In this paper, the evapotranspiration in Wushen County, located in the Mu Us Sandland, was estimated by Advection-Aridity Model with meteorological data and 1km resolution reflectance of NOAA/AVHRR from 1981 to 2000. Then the spatial and temporal distributions of the evapotranspiration in Wushen County were analyzed. The results show: (1) Advection-Aridity Model combined with remotely sensed data could estimate regional evapotranspiration better. (2) The annual mean evapotranspiration during 1981- 2000 in Wushen County is 264mm increasing from northwest to southeast while the annual mean precipitation is 320mm. (3) The temporal variation of evapotranspiration is in agreement with that of precipitation. (4) The relative variance of annual evapotranspiration is between 8% and 16%, which is the smallest in the eastern headwaters, bigger in the middle and the biggest in the north and southwest. Estimation of regional evapotranspiration plays a significant role in the study of the regional water resources management, the development of water-saving agriculture, and the hydraulic engineering. The Mu Us Sandland lies in the east of the Ordos Plateau, the northwest island of China. Because of abundant natural resources such as light, heat and so on, the Mu Us Sandland becomes an easier fathered sand land among the big area of deserts in China. The Wushen County lies in its middle area, where there is a little precipitation and the climate is dry, which become the main performances of weak environment and limit the development of economy. Therefore, it is very necessary to make good use of water resources, however, as an important source of information, reliable regional evapotranspiration is difficult to obtain. Remote sensing may estimate regional evapotranspiration precisely because it can provide relevant physical parameters in regional scale. In this paper, the evapotranspiration of Wushen County in the year 1981 to 2000 was estimated, combined with remotely sensed data and meteorological data, using one complementary relationship approach: Advection-Aridity Model. At last, the spatial and temporal distributions of the evapotranspiration in Wushen County were analyzed.