Research On Regional Evapotranspiration Regulations For Three Basins In ShanXin Province Based On Remote Sensing Data

ShanXi province is one of the most important energy and chemical base in ourcountry. With the rapidly development of economy, spread of urbanization andaggravation of contamination, the contradiction between development of economy ,entironment and water resource is outstanding. The land surface evapotranspirationis the important component of energy balance and the primary portion of waterbalance. It is not only important to the study on global climate evolvement,environment and the assessment of water resources, but also is vital to guide thedrainage and irrigation set-up, monitor droughts and improve water resource. Basinsare both main farm belt and industrial estate in ShanXi province, there is outstandingconflict between water supply and damand. It is vital to deeply study theevapotranspiration quantity and evapotranspiration distribution in time and space. Itis hopeful that this study will provide valuable ideas in the restoration andreconstruction of the ecoenvironment and using water resource.There are many traditional and imitational methods in calculatingevapotranspiration. These methods are high precision in singe station, but lowprecision in regional area because geometric structure and physical character areheterogeneous. With the development of remote sensing technology since the late1970s, it is new hope to solve the question. Comparing to the traditional methods, itis larger area of investigation, real time, economical, and better to reveal thedistribution of evaptranspiration in time and space.Based on surface energy balance theory, using SEBS model andNOAA/AVHRR data, through ENVI soft platform , it can be used to extract thesurface physical parameter and the surface energy flux and calculateevapatranspiration in the area .Temporal and spatial distribution of the area are known through analyzing theevapotranspiration of the three basins. The temporal and spatial evapotranspirationdistribution in the area are heterogeneous, July to September are the periods of highvalue, change from 70-150mm;January,February ,November,December are theperiods of low value, change from 10-30mm;the distribution of evapotranspirationforms a curve that has only one peak value. There many factors influencingevapotranspiration, including precipitation, temperature and the degree of vegetationcoverage etc. Correlation is existing between precipitation, temperature and thedegree of vegetation coverage with evapatranspiration by studying. It is significantto estimating evapotranspiration in other similar areas.