Evaluation of a satellite-derived model parameterized by three soil moisture constraints to estimate terrestrial latent heat flux in the Heihe River basin of Northwest China

Yunjun Yao; Yuhu Zhang; Qiang Liu; Shaomin Liu; Kun Jia; Xiaotong Zhang; Ziwei Xu; Tongren Xu; Jiquan Chen; Joshua B Fisher

doi:10.1016/j.scitotenv.2019.133787

Evaluation of a satellite-derived model parameterized by three soil moisture constraints to estimate terrestrial latent heat flux in the Heihe River basin of Northwest China

Sci Total Environ. 2019 Dec 10:695:133787. doi: 10.1016/j.scitotenv.2019.133787. Epub 2019 Aug 6.

Authors

Yunjun Yao¹, Yuhu Zhang², Qiang Liu³, Shaomin Liu⁴, Kun Jia¹, Xiaotong Zhang¹, Ziwei Xu⁴, Tongren Xu⁴, Jiquan Chen⁵, Joshua B Fisher⁶

Affiliations

¹ State Key Laboratory of Remote Sensing Science, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
² College of Resource Environment and Tourism, Capital Normal University, Beijing 100048, China. Electronic address: yuhu.zhang@cnu.edu.cn.
³ College of Global Change and Earth System Science, Beijing Normal University, Beijing 100875, China.
⁴ State Key Laboratory of Earth Surface Processes and Resource Ecology, Faculty of Geographical Science, Beijing Normal University, Beijing 100875, China.
⁵ CGCEO/Geography, Michigan State University, East Lansing, MI 48823, USA.
⁶ Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Dr., Pasadena, CA 91109, USA.

PMID: 31756871
DOI: 10.1016/j.scitotenv.2019.133787

Abstract

Satellite-derived terrestrial latent heat flux (LE) models are useful tools to understand regional surface energy and water cycle processes for terrestrial ecosystems in the Heihe River basin (HRB) of Northwest China. This study developed a satellite-derived hybrid LE model parameterized by three soil moisture (SM) constraints: SM, relative humidity (RH), and diurnal air temperature range (DT); and assessed model performance and sensitivity. We used MODerate Resolution Imaging Spectroradiometer (MODIS) and eddy covariance (EC) data from 12 EC flux tower sites across the HRB. The hybrid model was trained using observed LE over 2012/2013-2014, and validated using observed LE for 2015 and leave-one-out cross-validation. The results show that the three SM constraints schemes exhibited some modeling differences at the flux tower site scale. LE estimation using SM achieved the highest correlation (R² = 0.87, p < 0.01) and lowest root mean square error (RMSE = 20.1 W/m²) compared to schemes using RH or DT schemes. We then produced regional daily LE maps at 1 km × 1 km across the HRB for 2013-2015. Regional analysis shows that our LE estimates from all three constraint models exhibited large spatial variability and strong seasonal and annual variations, attributed to differences in parameterizing the model water constraints. This study provides data and model based evidence to improve satellite-derived hybrid LE models with regard to water constraints.

Keywords: Heihe River basin; MODIS; Soil moisture constraints; Terrestrial latent heat flux.