A satellite-based energy balance algorithm with reference dry and wet limits

Abstract

Based on the assumption of a linear relationship between near-surface temperature difference and radiometric surface temperature such as the surface energy balance algorithm for land (SEBAL), a satellite-based energy balance algorithm with reference dry and wet limits (REDRAW) is proposed to estimate evapo-transpiration (ET) for the regional scale. REDRAW supposes that extreme hydrological conditions can be represented by the reference dry and wet limits, which consist of four reference limits: reference bare soil dry limit (RBD), reference vegetated soil dry limit (RVD), reference bare soil wet limit (RBW), and reference vegetated soil wet limit (RVW). These reference limits should be derived geographically and used to estimate actual ET under common hydrological conditions. A comparison is made between REDRAW and a commonly used model, SEBAL, at two sites: the Tongyu in China and the Cabauw in The Netherlands. The performances in both cases show that REDRAW can provide more reliable ET estimation in relatively arid and humid areas. Meanwhile, error analysis shows that estimation of sensible heat flux is sensitive to meteorological data, and further study is needed to make REDRAW more robust to environmental conditions.