Evapotranspiration estimation using the Landsat-5 Thematic Mapper image over the Gyungan watershed in Korea

Abstract

Even if there have been efforts to validate remote-sensing-based energy balance models, which provide evapotranspiration (ET) maps over a large spatial scale, few studies have been conducted to validate their performance in Korea. In this study, surface energy balance fluxes including ET were estimated and inter-compared with two different models using the Landsat-5 Thematic Mapper (TM) image over a watershed scale in Korea. While there were larger spatial discrepancies for net radiation, soil heat and sensible heat fluxes on a pixel-by-pixel basis between the two models, relatively smaller spatial discrepancies for the latent heat flux and daily ET were detected. The spatial discrepancies for the daily ET were larger in low topography and dense vegetation ranges. Despite the different partitioning of the surface energy fluxes due to spatial variability, a remote-sensing-based surface energy balance approach appears to deliver the operational capability for ET estimation and mapping over a watershed scale in Korea.