A Comprehensive Evaluation of Surface Air Temperature Reanalyses over China against Urbanization Bias–Adjusted Observations

Abstract The reanalysis datasets (CRA40) have now been developed in China Meteorological Administration. We aim to compare the differences in surface air temperature (SAT) between observational that has been adjusted for urbanization bias and reanalysis data (NCEPV1, NCEPV2, ERA5, CFSR, MERRA, JRA55, 20CRV3 and CRA40) over mainland China during 1961–2015. The main results are presented as follows. The correlation and standard deviation between the reanalysis data and observations exhibit highly consistent interannual variability and dispersion, with the interannual SAT variability in JRA55 being closest to the observations for 1961–2015 and that of ERA5 for 1979–2015; the dispersions of 20CRV3 is most consistent with the observations for 1961–2015 and that of NCEPV1 for 1979–2015. Although annual mean SAT of the reanalysis is generally 0–2.0 °C lower than the observations, the bias in the SAT climatology of 20CRV3 is the least for 1961–2015 in all reanalysis datasets and that of CRA40 is the least for 1979–2015. The trends of NCEPV1 is closer to the observations than other reanalysis for 1961–2015 and that of 20CRV3 for 1979–2015. The biases in terms of interannual variability, dispersion, climatology, and linear trend are increase with altitude. Overall, in terms of the similarity of multiple measures to the urbanization bias-adjusted observations, JRA55 and CRA40 show the best performances for the periods 1961–2015 and 1979–2015 respectively in reproducing various aspects of climatological and climate change features in mainland China.