Study On Regional Evapotranspiration Estimation Using Remote Sensing Technology Of Extreme Arid Climate Area Based On SEBAL

Evapotranspiration is an important basis on distribution utilization of water resources. How to take the evapotranspiration values of different climatic environments and regions is seen as the key point in this field at present. The region evapotranspiration is estimated with remote sensing technology for the first time, and is inversed with SEBAL model which is much wider and maturer at home and abroad in medium sized irrigation district in KEKEYA, shanshan county which is typical extremely arid region in Xinjiang. Evapotranspiration in study area is estimated with remote sensing technology, and evapotranspiration estimation model which is suitable for extreme arid climate condition is established, which provide evidence for water resources planning, deficit irrigation schedule, etc. Evapotranspiration value is estimated with SEBAL model combined with Landsat5image data and meteorological data of meteorological stations on the ground in study area. The remote sensing retrieval result is verificated with evapotranspiration value calculated with Penman-Montieth formula using the detecting data with OPEC system installated in study area. The data is analyzed, the model parameters are corrected, and the evapotranspiration estimation model in extreme arid climate condition is established. TM datum selected in june, july, august, september in2010in study area are used to establish the SEBAL model, and daily image sampling evapotranspiration is inversed on the same day. The parameters in the model which are retrieval of the reflectivity, vegetation index, temperature, net radiation, soil heat flux and the specific position in study area are analyzed. A preliminary judgement of the model accuracy is taken, and the daily evapotranspiration value inversed by the model and calculated with meteorological data of meteorological stations on the ground are contrasted. The ground monitoring evapotranspiration values are separately4.93mm/d,5.18mm/d,5.64mm/d,4.38mm/d,3.97mm/d, the model inversing evapotranspiration values are5.02mm/d,4.8mm/d,5.46mm/d,4.54mm/d,3.86mm/d, and the maximum deviation is7.3percents.The daily evapotranspiration inversed by the established model and the measured data are contrasted, and the accuracy is above90percents, which means that it can applicate in evapotranspiration related study in this area. Evapotranspiration of different areas in the study area is studied in statistical way, and that of8different kinds of areas are contrasted, and the strong or weak relations of evapotranspiration ability judged.Situation is provide the basis for water consumption of different types of land...