Analysis on the change laws of evapotranspiration and its influencing factors in arid areas

This paper collects and summaries the existing materials, taking the field obersavations. The evapotranspiration in Ge´ermu area is estimated by combining hydrologic data and the remote sensing data, and the law of evapotranspiration distribution variation in study area was obtained statistically. So as to analyse the factors of influencing evapotranspiration. The result showed that many crucial physical factors, such as the energy supplying condition, the vapor transportation condition, and the ability of evaporation media to supply water influenced evapotranspiration in the process. Solar radiation may be the main energy supplying, saturation deficit and wind velocity will also decide the vapor transportation condition, moreover, the ability of evaporation media to supply water is depended on groundwater, the soil constitution and surface vegetation. The main factors influenced evapotranspiration in arid areas Climate conditions were the depth of groundwater table, the lithology of vadose zone, the rate of vegetation covering and so on.