METHODS OF DETERMINING EVAPOTRANSPIRATION USING SPACE TECHNOLOGIES

Abstract

Finding out how much water crops use is very important for agriculture and water management today. Evapotranspiration (ET) is the main indicator that helps us understand this water loss from soil and plants. In the past, people used tools on the ground to measure ET, but these traditional methods take too much time and are very expensive for large regions. Today, space technologies and remote sensing give us a much better way to map ET directly from space. This paper reviews different satellite-based methods used to find ET. We look at the role of various satellite sensors, such as MODIS (which provides daily images at 250m and 500m resolution), Landsat, Sentinel, and the newer ECOSTRESS sensor on the International Space Station. We also briefly discuss the common energy balance models used with these satellites, like SEBAL and METRIC. The main goal of this paper is to compare these different satellite technologies. In the discussion, we analyze which satellite or model is better for specific tasks, comparing them by spatial resolution and how often they take pictures. This comparison will help researchers and farmers choose the right remote sensing tool for specific water saving projects.