Intercomparison of remote sensing‐based models for estimation of evapotranspiration and accuracy assessment based on SWAT

Abstract

Abstract:An intercomparison of daily actual evapotranspiration (ET) estimates from the single-source models (SEBAL and SEBS) and the two-source models (P-TSEB and S-TSEB) using remotely sensed data was performed to examine their utilities and limitations under a wide range of land covers and different meteorological conditions. The accuracy of ET estimates from remote sensing-based models of a selected watershed on 23 June 2005 (DOY 174) presenting large air drying power and marked contrast in underlying surface characteristics, and 25 July 2005, (DOY 206) in contrast to the meteorological and underlying surface conditions of DOY 174, were evaluated in terms of SWAT-based ET. The ET estimates from the two methodologies are shown to be comparable, indicating that S-TSEB has the highest accuracy with relative errors of 2Ð2% and 5Ð6% with reference to SWAT-based ET for DOY 174 and 206, respectively. Hence it was selected to be the basis for performing an intercomparison with other remote sensing-based models. Single-source models are very sensitive to KB 1 parameter, rendering marked differences in ET estimates because of different treatments of roughness length for heat transfer. SEBAL and SEBS yielded mean absolute percentage difference (MAPD) versus S-TSEB within 26Ð22% and 26Ð56% for DOY 174 and within 9Ð11% and 11Ð69% for DOY 206, respectively, indicating their applicability to higher vegetation cover and soil moisture availability areas under small air drying power condition. P-TSEB generated MAPD versus S-TSEB within 41Ð15% for DOY 174 and 8Ð79% for DOY 206, implying that P-TSEB is highly consistent with S-TSEB under small air drying power and less contrast in soil moisture conditions, whereas noticeable discrepancies occur under large air drying power and marked contrast in soil moisture circumstances, in particular for sparse cover. The performance of P-TSEB largely depends on the meteorological and underlying surface conditions, both exerting significant influences on the extent of coupling between vegetation and soil.

Three perceptions of the evapotranspiration landscape: comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances

“…The remaining noise of the remote sensing estimations compared to the SWIM results in the upper left panel in Fig. 14 is indicated by a correlation coefficient of 0.613. This is clearly within the range observed by most recent studies evaluating remotely sensed ET by estimations from other methods, be it reference ET calculated from lysimeter measurements (Wloczyk, 2007;Sánchez et al, 2008), eddy flux or other micrometeorological tower measurements (Verstraeten et al, 2005;Patel et al, 2006;McCabe and Wood, 2006;Brunsell et al, 2008;de C. Teixeira et al, 2009), or hydrological model simulations (Boegh et al, 2004;Gao and Long, 2008;Galleguillos et al, 2011).…”

Evapotranspiration Estimation with Remote Sensing and Various Surface Energy Balance Algorithms—A Review

“…Note that SEBS has been widely applied over large heterogeneous areas fed with MODIS data with thermal band information of 1 km [15,84]. However, relatively complex solution of the turbulent heat fluxes and too many required parameters can often cause more or less inconveniences in SEBS when data are not readily available.…”

Development of a Simple Remote Sensing EvapoTranspiration model (Sim-ReSET): Algorithm and model test

“…Results of the comparisons between single-source and dual-source ET models show that the accuracy of dual-source models is much better than that of single-source models, especially in sparsely vegetated areas (Gao and Long, 2008;Timmermans et al, 2007). In this study, therefore, the main objective is to develop a new dual-source Simple Remote Sensing EvapoTranspiration model (Sim-ReSET) based on the energy balance of the land surface.…”