M Y; S B; Z I; H S
Abstract
Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field ...
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Accurate estimation of evapotranspiration plays an important role inquantification of the water balance at regional scale for better planningand managing water resources. Evapotranspiration can be obtained fromeither estimation of potential ET using data of meteorological stations or,directly, from field measurements. ET is subject to rapid changes in timeand space, attributable to the wide spatial variability of precipitation,hydraulic characteristics of soils, and vegetation types and densities.Therefore, it is nearly impossible to determine its spatial and temporaldistributions over large areas only from lysimeter and precise measuringinstruments. Thus, researchers have used remote sensing data to estimateareal actual ET. In this study, actual evapotranspiration variations ofNeyshabour plain was investigated by algorithm of energy balance of theearth since 2000 to 2013 by using MODIS images and meteorologicaldata. Also, the determined evapotranspiration was compared and evaluatedwith Penman-Monteith and Hargreaves-Samani models. Low amount ofcoefficients of the error between Penman-Monteith model and SEBALalgorithm showed the accuracy of SEBAL model in the estimation ofevapotranspiration and its parameters. The results derived fromcomparison of evapotranspiration and NDVI vegetation index indicated agood correlation between vegetation and evapotranspiration (R2=0.908).Also, the variations of NDVI index, land surface temperature, andevapotranspiration in the studied fields showed that evapotranspirationincreased by lower land surface temperature and higher densities ofvegetation.