不同分辨率CCSM4对东亚和中国气候模拟能力分析

摘要

本文利用通用气候系统模式CCSM4在三种水平分辨率下的工业化革命前期气候模拟试验,结合观测和再分析资料,比较了各分辨率下模式对中国温度和降水、东亚海平面气压和850hPa风场的模拟能力,综合评价了模式分辨率对东亚和中国气候模拟的影响.结果表明,三种分辨率对中国温度均具有很好的模拟能力,除春季外,低分辨率(T31,约3.75°×3.75°)对全年温度的模拟能力均要稍好于中(f19,约1.9°×2.5°)、高(f09,约0.9°×1.25°)分辨率；各分辨率对中国降水的模拟能力远不如温度,除冬季外全年都出现的中部地区虚假降水并未因为模式分辨率提高而得到本质改善；对于东亚海平面气压场,低分辨率在冬季模拟能力相对最好,中等分辨率在夏季相对较好,而高分辨率的模拟能力均表现最差；低分辨率对850hPa东亚冬季风和夏季风的模拟能力均要好于中、高分辨率,而两种较高分辨率的模拟能力则比较接近.总的来说,低分辨率CCSM4在东亚和中国气候模拟中表现出了较大优势,加之其计算代价小,适合进行需要较长时间积分的气候模拟研究.%By utilizing the pre-industrial climate simulation outputs from the Community Climate System Model version 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 fl9, with a grid spacing of approximately 1.9°X2.5°, and the high-resolution fO9, with a grid spacing of approximately 0.9°X 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.