The response of actual evaporation to global warming in China based on six reanalysis datasets

摘要

In this paper, we present the response of actual evaporation to global warming in China based on the National Centers for Environmental Prediction-National Center for Atmospheric Research (NCEP/NCAR) reanalysis 1, the NCEP-Department of Energy (NCEP/DOE) reanalysis 2, 40-year ECMWF Re-Analysis (ERA-40), ECMWF-Interim Re-Analysis (ERA-Interim), Modern-Era Retrospective Analysis for Research and Applications (MERRA), and Climate Forecast System Reanalysis (CFSR). Rotated empirical orthogonal function (REOF) analysis was applied to reveal the coherent pattern of the change in reanalysis evaporation (RE). According to the first four REOF modes in NCEP/NCAR, we subdivided China into six climatic regions, and found that RE increased significantly in central and southeast of China from 1979 to 2012, especially during the sub-period of 1985-2004. Various estimates of linear trend are statistically consistent, and most of them are significant at the 95% confidence level. Conversely, RE decreased in northern and northeast although the magnitude of decreasing trends is inconsistently among the reanalysis. Moreover, there is a general tendency of RE to increase in northwest, but mostly RE trends are not significant. In the dry northwest and northern regions, rainfall is an important factor affecting the changing of RE, while RE is less sensitive to the change of temperature. However, RE rates are dominated by temperature in the humid central and southeast regions. These results support the view that the sensitivity of RE to global warming largely depends on the environment. In view of data availability, despite the general similarity, differences exist among the various reanalysis, especially in NCEP/NCAR and CFSR. In summary, it can be concluded that the quality of RE values is higher in central and southeast, while even greater uncertainties lie in the estimates of RE in northwest China and Qinghai-Tibet Plateau.