Validation of the operational simplified surface energy balance products and spatiotemporal changes in evapotranspiration in China from 2003 to 2016

Evapotranspiration (ET) is an important part of the hydrological cycle. It is essential to evaluating the accuracy of different ET products in practical applications. The operational simplified surface energy balance (SSEBop) ET products are widely used because of their high resolution. The SSEBop products were validated at the site and basin levels using eddy covariance data from ChinaFLUX stations and compared with that of the MOD16 products in China. The results are as follows: (1) at the site level, SSEBop ET and MOD16 ET showed overall comparable accuracies; at the basin level, the annual ET simulation values of the SSEBop and MOD16 products were biased toward high values, and the accuracy of the SSEBop products was better than that of the MOD16 products. (2) The distribution of China's multiyear ET pattern obtained from the SSEBop products is reasonable. The largest change in annual ET obtained by the SSEBop products is in the Songhua River Basin, whereas the smallest is in the Southwestern Rivers. Therefore, the results demonstrate that the SSEBop products provided reliable ET estimations at multiscales and performed well in the simulation of spatiotemporal variation of ET in China, which is of great significance to regional water resource management and efficient water utilization in China. (C) 2020 Society of Photo-Optical Instrumentation Engineers (SPIE)