Satellite Based Evapotranspiration Estimation Using Sebal Model: Application of Remote Sensing and G.i.s. Techniques

Evapotranspiration (ET) is an important part in surface energy and water balance. ET is the process where liquid water is converted into water vapor and thus removed from sources such as the soil surface, wet vegetation, pavement, water bodies, etc. Transpiration consists of the vaporization of liquid water within a plant and subsequent loss of water as vapor through leaf stomata. Remote sensing based energy balance models are presently most suited Surface Energy Balance Algorithm for Land (SEBAL), a remote sensing based ET model, was applied to Landsat TM imagery in Bankura district, a tropical region in West Bengal with heterogeneous surface conditions, for the estimation of actual ET. SEBAL model follows an energy balance approach of estimation of ET, when the net radiation, sensible heat flux and soil heat flux are known. Input for SEBAL model includes land surface parameters such as surface temperature, NDVI and albedo.