GEE RET: Cloud-based reference evapotranspiration calculation with google earth engine

Abstract

Reference Evapotranspiration (RET) is one of the fundamental variables for water resource management and finds applications in various fields such as irrigation sciences, environmental studies, and hydrology. However, its calculation can be complex, leading to research delays or reliance on outdated datasets, which may introduce errors in the results. Therefore, in this study, we developed an online software named GEE RET for calculating RET and accessing meteorological data based on Google Earth Engine. The aim of GEE RET was firstly to create a simple and efficient tool for calculating and accessing RET and meteorological data globally and online; secondly, to access long-term RET in the absence of meteorological data; and thirdly, to generate RET in areas where weather stations are not available. In GEE RET, the complex steps of calculating RET are performed through cloud processing, and users can access these data simply by specifying their desired area. Additionally, GEE RET provides access to reference and actual evapotranspiration from the WaPOR dataset. Achieving these goals assists researchers in easily accessing meteorological variables and RET at any point on Earth without the need for learning various sciences such as remote sensing or programming and without the need for processing large volumes of data, while also facilitating the use of up-to-date data. This software is freely accessible on the website [https://rahmanbarideh.users.earthengine.app/view/ret].