Evaluation of Eight Current Reanalyses in Simulating Land Surface Temperature from 1979 to 2003 in China

Land surface temperature T-s provides essential supplementary information to surface air temperature, the most widely used metric in global warming studies. A lack of reliable observational T-s data makes assessing model simulations difficult. Here, the authors first examined the simulated T-s of eight current reanalyses based on homogenized T-s data collected at similar to 2200 weather stations from 1979 to 2003 in China. The results show that the reanalyses are skillful in simulating the interannual variance of T-s in China (r = 0.95) except over the Tibetan Plateau. ERA-Interim and MERRAl and versions perform better in this respect than ERA-Interim and MERRA. Observations show that the interannual variance of T-s over the north China plain and south China is mostly influenced by surface incident solar radiation R-s, followed by precipitation frequency, whereas the opposite is true over the northwest China, northeast China, and the Tibetan Plateau. This variable relationship is well captured by ERA-Interim, ERA-Interim land, MERRA, and JRA-55. The homogenized T-s data show a warming of 0.34 degrees C decade(-1) from 1979 to 2003 in China, varying between 0.25 degrees and 0.42 degrees C decade(-1) for the eight reanalyses. However, the reanalyses substantially underestimate the warming trend of T-s over northwest China, northeast China, and the Tibetan Plateau and significantly overestimate the warming trend of T-s over the north China plain and south China owing to their biases in simulating the R-s and precipitation frequency trends. This study provides a diagnostic method for examining the capability of current atmospheric/land reanalysis data in regional climate change studies.