中文摘要：

本文利用全球海气耦合模式（MIROC3.2_hires）和区域气候模式（RegCM3）的模拟结果,分析了东亚地区夏季降水和大气环流的季节演变特征,并与NCEP/DOE再分析资料和降水观测资料进行了对比分析。结果表明,全球和区域气候模式都能反映出中国东部地区夏季平均环流场和降水场气候态分布的基本特征,但全球模式模拟的雨带范围偏大,几乎覆盖整个华南地区,区域气候模式则较好地模拟出华南沿海地区的降水大值中心,与实际观测更相符。对于季节演变特征而言,全球模式模拟的华南前汛期和江淮梅雨期的主要降水中心均位于华南地区,未能反映出北推过程,而区域模式能够模拟出中国东部地区夏季雨带随时间呈现出的北推过程,即华南前汛期、江淮梅雨期和华北与东北雨季三个阶段。区域模式对东亚高空急流和对流层低层南风场随时间北移的模拟能力明显优于全球模式,这可能是区域模式能够改进对降水季节演变模拟的重要原因。

英文摘要：

The authors compared the simulations of seasonal evolution of rainfall over eastern China and the associated large-scale circulation during summer by a coupled general circulation model （CGCM, MIROC3.2_hires） and the nested regional climate model （RegCM3）. Results show that both the MIROC3.2_hires and RegCM3 can reproduce the basic features of summer mean atmospheric circulation, and the spatial distribution of precipitation in China characterized by a decrease from the southeast to northwest of China. Compared with observations, the MIROC3.2_hires simulates a more extensive area of heavy rainfall over South China, while the RegCM3 presents more reasonable spatial distribution of rainfall over this region. The improvement of simulation by RegCM3 is more evident in the seasonal evolution than that by the driving CGCM. It is found that the MIROC3.2_hires fails to reproduce the seasonal evolution of rain band by presenting the precipitation maximum stagnating over South China during the whole summer period. Meanwhile, the RegCM3 can basically capture the seasonal evolution of rainfall over eastern China during summer, characterized by three stepwise stages, i.e. pre-summer rainy season in South China, Meiyu period in the Yangtze River valley, and rainy season in North China. It suggests that the better simulation of seasonal evolution of wind in both the lower and upper troposphere may be important for the improvements of RegCM3 in simulating the seasonal rainfall evolution.