Northwest Inland Areas Evapotranspiration Study Basing On The SEBAL Model

The evapotranspiration, as the main carrier of transporting water vapor from land intoatmosphere system, is an important link of the hydrologic cycle in atmospheric dynamichydrological system. Evapotranspiration has important influence on atmospheric watervapor content, water vapor transfer and cloud to rain. Estimating evapotranspirationreasonably and accurately has great value to solve water resources shortage in ournorthwest inland areas. It’s also important for artificial rainfall using atmospheric waterresources.This paper employed modified SEBAL model and MODIS product to estimatingevapotranspiration in Shiyang River Basin. This paper increased the slope and aspectresearch, analysed the different land use region and fitted the relativity betweenland-surface parameters and daily evapotranspiration. Concrete research points as follows:1）The modified SEBAL model feasibility in survey region was verified by comparingmeasured daily evapotranspiration with the same period estimate. The result of modifiedmodel was more close to the measured value by comparing modified model with masterpatern.2）Statistical analysis of annual daily evapotranspiration in survey region revealed thataverage daily evapotranspiration in Shiyang River Basin was4.12mm/d in2005and dailyevapotranspiration in March to September was larger.3）The results show that the Normalized Differential Vegetation Index, AtmosphericTransmittance and Emissivity to daily evapotranspiration are positive correlations; Slope,Temperature and Surface Albedo to daily evapotranspiration are anticorrelations, andAspect to evapotranspiration is triangular curve relationship. The south is for peak valueand the north is for valley value. The daily evapotranspiration of woodland, cold desert,water area and marsh is high, but the daily evapotranspiration of the sand, the gobi and saline and alkaline land is low.The modified SEBAL model feasibility in calcuting in our northwest inland areaswas verified by analysis, which afforded foundation for further optimizing model andsupplied reference for managing atmospheric-water resources reasonably.