Evapotranspiration Estimation Using Surface Energy Balance System Model: A Case Study in the Nagqu River Basin

Lei Zhong,Xian Wang,Kepiao Xu,Yaoming Ma,Nan Ge,Ziyu Huang

doi:10.3390/atmos10050268

Abstract

Calculation of actual evapotranspiration (AET) is of vital importance for the study of climate change, ecosystem carbon cycling, flooding, drought, and agricultural water demand. It is one of the more important components in the hydrological cycle and surface energy balance (SEB). How to accurately estimate AET especially for the Tibetan Plateau (TP) with complex terrain remains a challenge for the scientific community. Using multi-sensor remote sensing data, meteorological forcing data, and field observations, AET was derived for the Nagqu river basin of the Northern Tibetan Plateau from a surface energy balance system (SEBS) model. As inputs for SEBS, improved algorithms and datasets for land surface albedo and a cloud-free normalized difference vegetation index (NDVI) were also constructed. The model-estimated AET were compared with results by using the combinatory method (CM). The validation indicated that the model estimates of AET agreed well with the correlation coefficient, the root mean square error, and the mean percentage error of 0.972, 0.052 mm/h, and −10.4%, respectively. The comparison between SEBS estimation and CM results also proved the feasibility of parameterization schemes for land surface parameters and AET.

Highlights

Actual Evapotranspiration (AET), which is the water lost to the atmosphere from the land surface [1], is a crucial component of the terrestrial water cycle and energy balance [2,3].In addition, accurate AET information at a regional scale is critical for quantitative understanding of land-atmosphere interactions and providing valuable means to efficiently use water resources [4,5].it is difficult to measure AET through point observation in remote mountain regions, such as the Tibetan Plateau (TP), which has harsh climate conditions
This study aims to test the feasibility of the surface energy balance system (SEBS) model to derive the AET at a local basin scale
The albedos derived from the improved method were in good agreement with in situ measurements with a correlation coefficient, a root mean square error, and a mean percentage error of 0.606%, 0.076%, and

Summary

Introduction

Actual Evapotranspiration (AET), which is the water lost to the atmosphere from the land surface [1], is a crucial component of the terrestrial water cycle and energy balance [2,3].In addition, accurate AET information at a regional scale is critical for quantitative understanding of land-atmosphere interactions and providing valuable means to efficiently use water resources [4,5].it is difficult to measure AET through point observation in remote mountain regions, such as the Tibetan Plateau (TP), which has harsh climate conditions. Actual Evapotranspiration (AET), which is the water lost to the atmosphere from the land surface [1], is a crucial component of the terrestrial water cycle and energy balance [2,3]. Accurate AET information at a regional scale is critical for quantitative understanding of land-atmosphere interactions and providing valuable means to efficiently use water resources [4,5]. It is difficult to measure AET through point observation in remote mountain regions, such as the Tibetan Plateau (TP), which has harsh climate conditions. For the water cycle, the TP contains the headwaters of major rivers in Asia and is often referred to as the ‘Asian Water Tower’ [9]

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Results

Discussion

Conclusion