Introduction and Development of Actual Evapotranspiration Estimation Toolbox by Using METRIC Algorithm (Case study: Urmia Plain)

Evapotranspiration is one of the key components of water balance in a basin. In recent decades, several methods and models have been developed for estimating evapotranspiration using remotely sensed data. In this context, utilizing the surface energy balance equation has led to the development of Surface Energy Balance (SEB) models, such as SEBAL and METRIC. Despite the extensive usage of these models, their application is still challenging due to the underlying algorithm complexity and the time consuming process of selecting cold and hot pixels by an experienced user. The goal of this study is to develop and introduce a new toolbox within the MATLAB environment for estimating actual evapotranspiration using the METRIC algorithm and Landsat 8 imagery. Unlike the previously developed models based on the METRIC algorithm, the selection of hot and cold pixels has been made automatic in this new toolbox. The toolbox was also used to estimate actual monthly evapotranspiration of the Urmia plain in 2016, and the results were compared with those obtained from the MODIS images to highlight the applicability of high spatial resolution imagery in water and agricultural management studies.