Estimation of Surface Energy and Day Evapotranspiration in a Dry-Farming Region of Northwest China using Satellite Data

Abstract

By using observation data of land process and EOS/MODIS data, the surface parameters, energy flux and day evapotranspiration in the dry-farming region in Northwest China are derived. The result shows that surface characters of the region are well reflected by retrieval values from EOS/MODIS. Most of the relative errors of different parameters are less than 20%. There are asymmetry distributions of flux and day evapotranspiration of the region. The current of seasonal variety is of a single-apex model, which is lower in winter and higher in summer. Comparing with the region with middle and low vegetation fractions, the values of some parameters are higher for the region with a higher vegetation fraction, which include net radiation, latent heat flux and day evapotranspiration. The values of other parameters are lower, such as soil heat flux and sensible heat flux. The characters of all these parameters are more prominent in spring and summer. Seasonal variety of energy flux in middle and low vegetation fraction region is not obvious, showing that dry soil is thick in the dry-farming region in Northwest China.