Estimation of evapotranspiration for the blown-sand region in the Ordos basin based on the SEBAL model

Abstract

ABSTRACTEvapotranspiration plays a crucial role in the surface hydrothermal balance. On a regional scale, especially in the blown-sand areas, an accurate estimate of evapotranspiration has important guiding significance for a rational allocation of water resources and drought monitoring. The objective of the study is to estimate the surface evapotranspiration for the blown-sand region in the Ordos Basin based on the Surface Energy Balance Algorithm for Land (SEBAL) model using six phases of Landsat 8 remote sensing images during 2015–2016 and the corresponding surface meteorological observational data, analyze the characteristics of temporal and spatial distributions of evapotranspiration in the study area. The results show that (1) the daily evapotranspiration presents a seasonal variability with the highest in summer, lower in autumn and spring, and the lowest in winter; (2) the evapotranspiration is distinctly characterized by its spatial variability, which is related to the terrain and geomorphology in this area as well as the effect of human activities; and (3) the daily evapotranspiration estimated by the SEBAL model was validated using the Food and Agriculture Organization (FAO) Penman-Monteith (P–M) model, which yielded an mean relative error (MRE) of 19.5%. In summary, the remote sensing data based SEBAL model can be applied to robustly estimate evapotranspiration for the blown-sand regions, and the study results can be served as an important reference for the research of water circulation, rational utilization of water resources, and protection of the ecological environment in the arid and semi-arid regions.