ISSN: 2474-8846
Authors: El-Shirbeny MA*
The evapotranspiration (ET) is a combination of evaporation and transpiration. Where the water is lost from the soil surface and from the crop canopy. The evaporation (E) and transpiration (T) occur instantaneously with no distinguishing between theme. During bare soil stage the E is the dominant process while the T is the effective one when the crop coverage is 100%. The ET is affected with weather conditions, crop features, management and environmental features. The ET methods varied based on the complexity of the model. The air temperature (Ta) is the most critical driving factor which has been used in all ET estimation models. Solar radiation (Ra) intensity and period have been involved in most models. Relative humidity (RH) and wind speed (U) are important parameters affecting on vapor pressure deficit (VPD). The VPD gradient is the most limiting factor affecting the ET rate. Remote sensing is a promising technology. It is prepared to be instead of traditional technologies in the future. The NDVI is a good physical indicator for earth’s land cover classes. The surface temperature results are related to the substance’s potential energy. Scientists still search out to find a way of using remote sensing as a stand-alone technology. A short review on ET models and its new trends are the main target of this work.
Keywords: Evapotranspiration; Estimation; Irrigation; Temperature; Pressure
