Monitoring of Evapotranspiration in a Semi-Arid Inland River Basin by Combining Microwave and Optical Remote Sensing Observations

Abstract

Abstract:As a typical inland river basin, Heihe River basin has been experiencing severe water resource competition between different land cover types, especially in the middle stream and downstream areas. Terrestrial actual evapotranspiration (ETa), including evaporation from soil and water surfaces, evaporation of rainfall interception, transpiration of vegetation canopy and sublimation of snow and glaciers, is an important component of the water cycle in the Heihe River basin. We developed a hybrid remotely sensed ETa estimation model named ETMonitor to estimate the daily actual evapotranspiration of the Heihe River basin for the years 2009-2011 at a spatial resolution of 1 km. The model was forced by a variety of biophysical parameters derived from microwave and optical remote sensing observations. The estimated ETa was evaluated using eddy covariance (EC) flux observations at local scale and compared with the annual precipitation and the MODIS ETa product (MOD16) at regional scale. The spatial distribution and the seasonal variation of the estimated ETa were analyzed. The results indicate that the estimated ETa shows reasonable spatial and temporal patterns with respect to the diverse cold and arid landscapes in the upstream, middle stream and downstream regions, and is useful for various applications to improve the rational allocation of water resources in the Heihe River basin. OPEN ACCESSRemote Sens. 2015, 7 3057

Development of an Evapotranspiration Data Assimilation Technique for Streamflow Estimates: A Case Study in a Semi-Arid Region

“…A synthetic data experiment and a real data experiment were carried out for a semi-arid basin to validate the efficacy of the state augmentation direct insertion method. The results show that the state augmentation direct insertion (DI) assimilation method can achieve an acceptable streamflow estimation improvement with a reliable ET observation, which derived from the combination of multisource remote sensing data and ET model with multiple parameterizations [37].…”

“…Besides calibration, assimilating a reliable ET product into gridded SWAT improves the streamflow prediction in the upper Heihe River Basin. This kind of ET product integrating low bias forcing data and comprehensive ET modeling process is better than observed or modeled ET alone [37]. With this kind of ET data, GSWATET can correct errors in ET modeling and other related variables modeling.…”

“…The evaporation from water surface was estimated using the classical Penman equation [40]. Sustainability 2017, 9, 1568 7 of 21 Evapotranspiration data was produced based on remote sensing-based ETMonitor model [37] and WRF (Weather Research and Forecasting) model data by Cui and Jia [38]. With a variety of parameterization methods of the aerodynamic and bulk surface resistances, the estimation of soil evaporation and vegetation transpiration was based on the Shuttleworth-Wallace Dual-Source model.…”

Hydrologic and Cryospheric Processes Observed From Space

“…Monthly ET at 1 km x km spatial resolution; China, July 2010 (Hu and Jia, 2015) resolution DEM and integrating the sub-pixel adjacency effect. A time series of daily instantaneous, i.e.…”

“…The hybrid remotely sensed ET estimation model named ETMonitor (Hu and Jia, 2015) was applied to estimate the daily actual ET globally and evaluated against eddy covariance measurements at sites in China (Fig.3) and Europe. The model is forced by a variety of biophysical parameters derived from microwave and optical remote sensing observations.…”