Estimating daily evapotranspiration in Wuding River Basin based on MODIS remote sensing data

The daily evapotranspiration in Wuding River Basin was simulated based on the Nishida's model with the remote sensing data. First, this model was used at Yucheng Ecological Experiment Station, Chinese Academy of Sciences on sunshine days from 2001 to 2002 to calculate the single point daily evapotranspiration, and the simulated results were compared with the observations from lysimeter. It is shown that the correlation coefficient between the simulated data and the observations is 0.61. The model was used to simulate the daily evapotranspiration in Wuding River Basin and the result shows that there exists obvious spatial variation of evapotranspiration where the daily evapotranspiration values in the northeast are less than that in the southwest evidently in August of three years from 2001 to 2003. As is well known, there are a lot of desert in the northeast and plenty of farmlands in the southwest. From the spatial distribution on the 222nd day of 2001, it can be found that the evapotranspiration along the valley of the Wuding River is higher than other parts, due to the relative abundance of soil moisture. In addition, the differences of the average daily evapotranspiration of different land use/coverage types are not significant.