Using the surface energy balance algorithm model to calculate evapotranspiration in Luhun irrigation area

Abstract

【Objective】 Evapotranspiration in terrestrial ecosystems is not only a component of hydrological cycle but also controls plant productivity. Understanding its spatiotemporal variation in a region is hence important for improving its water and agronomic management. This paper is to present a method for accurately and rapidly evaluating evapotranspiration at high spatial resolution in irrigation areas using remote sensing technology and energy balance model. 【Method】 The model is based on the surface energy balance algorithm (SEBAL) model by using Landsat-8 remote sensing imageries and meteorological data. Using this model, we calculate the evapotranspiration in the Luhun Irrigation area and analyzed its variation. 【Result】 The simulated SEBAL values are strongly correlated with both evapotranspiration products (v 1.5) and ground-true data, with the associated correlation coefficients exceeding 0.8 and 0.96, respectively. As plants grow, their evapotranspiration increases progressively from February to May, with the evapotranspiration in cropped regions higher than that in forested regions. Peak evapotranspiration is 106.52 mm, occurring from June to July primarily in cropped regions. The evapotranspiration decreases from August to September, with the region having higher evapotranspiration shifting toward the northeast of the region. 【Conclusion】 Using remote sensing satellite imagery and other complementary data, the SEBAL model is accurate for estimating evapotranspiration at high spatial resolution in a region. It has important implication for improving irrigation management in irrigation districts.

Keywords

• actual evapotranspiration
• sebal model
• crop growth period
• spatial autocorrelation