Spatiotemporal Characteristics of Actual Evapotranspiration Changes and Their Climatic Causes in China.

As the main expenditure item in water balance, evapotranspiration has an important impact on the surface ecosystem. Assessing the impact of changes in meteorological elements on evapotranspiration is essential to identify the spatiotemporal heterogeneity of hydrographic responses to climate changes. Based on the actual evapotranspiration (ET_a) product (GPR-ET) generated by Gaussian process regression (GPR), as well as temperature and precipitation datasets, our study employed various statistical analysis methods, including geographic detector, the center of gravity migration model, spatial variation coefficients, and partial differential models, to investigate the spatiotemporal variation in ET_a in China from 2000 to 2018. The analysis covered future trends in ET_a changes and the contribution of meteorological factors. Our results showed that the ET_a in northwest China had stronger spatial heterogeneity and the mean value was generally lower than that in the southeast. But the center of gravity of ET_a was shifting towards the northwest. In most areas, the future trend was expected to be inconsistent with the current stage. ET_a in the regions of north and west was mainly driven by precipitation, while its increase in southeast China was largely attributed to temperature. In addition to spatial variations, the joint enhancement effect of temperature and precipitation on ET_a exists. According to the contribution analysis, precipitation contributed more to the change in ET_a than temperature. These findings have enhanced our comprehension of the contribution of climate variability to ET_a changes, providing scientific proof for the optimization apportion of future water resources. [ABSTRACT FROM AUTHOR]