The Regional Evapotranspiration Research Based On The Modified SEBAL Model

Water is all of this, to ensure the survival of mankind, maintain the sustainable development of society, economy and environment. In the process of water exchange, energy is also transmitted along with water exchange. Water exchange between the surface and the atmosphere actually involves matter and energy at the same time. In this process, the evaporation is an integral part of water and energy balance between surface and the atmosphere. The traditional evapotranspiration estimation method are mainly affected by the limitation of time and space.The evapotranspiration estimation result is often just a point value, so it’s not typical. The use of remote sensing technology makes the evapotranspiration research extension in time and space scales, improve the accuracy of the estimation Based on SEBAL model, applying TM image in combination with DEM data and meteorological data, his thesis selects BengBu city, AnHui province as the research area and studies Remote sensing estimation research of area evapotranspiration. In this research, the author uses ENVI and ArcGIS software to process different data, such as cutting% resampling and terra-in classification of remote sensing image and DEM data, and requires a lot of intermediate data in evaporation estimation. The thesis mainly studies the principle of remote sensing image radiation correction and atmospheric correction by 6S. Besides, the thesis achieves the raster and vector transformation of DEM data. With evapotranspiration inversion model to estimate the evaporation in the research area on January 27th, March 27, May 14, July 30, October 2, According to the measured data of ground observation results are verified and analyzed. The ground monitoring evapotranspiration values are separately 133mm/d、3.21mm/d、4.61mm/d、6.94mm/d、 4.5mm/d, the model inversing evapotranspiration values are 1.52mm/d、3.17mm/d、 4.83mm/d、 6.54mm/d、4.73mm/d and the deviation are 14.2%、-2.3%、4.1%、-4.8%、 5.1%.It can prove that the model in the research area had a high estimation precision. And in view of the differences between time scale extension methods compared the EF method, improved EF method, main relations, astronomical radiation method. Show that evapotranspiration based on the technology of remote sensing inversion will have a high accuracy of estimation with using EF method and improved EF method. The affected factors of evapotranspiration are analyzed, including temperature, altitude, slope and so on. The result showed that positively correlated relationship between temperature and evaporation, while negatively related with the elevation gradient.In view of the large amount of calculation This study based on the IDL language to compile model algorithm, realized the integrating calculation and analysis function of evaporation inversion procedure, meet the needs of the professional users.