Evaluation of the Performance of Low- to High-Resolution CCSM4 over East Asia and China
不同分辨率CCSM4对东亚和中国气候模拟能力分析

By utilizing the pre-industrial climate simulation outputs from the Community Climate System Model ver- sion 4 (CCSM4) at three horizontal resolutions, the results of surface air temperature and precipitation in China and sea level pressure and wind field at 850 hPa over East Asia are compared with observation and reanalysis data to evaluate the model performance under the three resolution versions. In addition, the role of the resolution in climate simulation over East Asia and China is investigated in this study. Results indicate that all three resolution versions of CCSM4 show good performance in reporting surface air temperature in China. Except in spring, the low-resolution T31, with an equivalent grid spacing of approximately 3.75°, generally performed slightly better than did the moderate-resolution f19, with a grid spacing of approximately 1.9°×2.5°, and the high-resolution f09, with a grid spacing of approximately 0.9°×1.25°. The simulation of precipitation in China is less accurate than that of surface air temperature under all resolutions. Reproduction of a simulated precipitation center over central China occurring year-round except in winter does not essentially improve as the model resolution increases. For sea level pressure over East Asia, the low-resolution version shows the best performance in winter, and the moderate-resolution version performs best in summer, whereas the high-resolution performance is the least accurate in winter and summer. The East Asian winter and summer monsoon circulations at 850 hPa are reproduced far better at low-resolution than those at moderate- and high-resolutions, with the latter two resolutions showing similar capability. Overall, the low-resolution version of CCSM4, with a low computational cost, is effective for climate simulation over East Asia and China and shows promise for long-term climate simulations.