中文摘要：

利用区域气候模式RegCM3对1998年夏季东亚区域气候进行了季节尺度模拟，并通过小波分解方法对长江中下游地区观测和模拟的气象要素进行多尺度分析，旨在研究区域气候模式对长江中下游地区夏季大气多尺度振荡的模拟能力。结果表明：模式对降水低频振荡的模拟要优于对其它振荡周期的模拟，而对降水高频振荡和天气尺度周期振荡的描述能力相对较弱。模式对整个对流层温度模拟偏低，且主要表现在对低频温度模拟偏低。对流层下层温度模拟误差主要是由对高频温度振荡的模拟误差造成的，对流层上层温度模拟误差主要是低频温度振荡的模拟误差造成的。由于高频温度所占方差贡献很小，因此，提高模式对整层大气低频温度变化的模拟能力显得更为重要，但总体上各种时间尺度温度振荡和梅雨期降水振荡之间并不存在对应关系。除涡度的8天周期振荡外，涡度的其它周期振荡和降水振荡之间具有较好的对应关系，梅雨降水集中期主要与16天以上涡度低频振荡和4天以下涡度高频振荡相对应，涡度天气尺度周期振荡对梅雨期降水的贡献不大。涡度振荡分量周期越长，其模拟与观测之间相关系数的垂直变化就越大，且不论周期长短，涡度各周期分量方差贡献的大小都基本相同。

英文摘要：

The purpose of this paper is verifying the ability of regional climate model to reproduce the multi-scale oscillation over the lower and middle reaches of Yangtze River in summer, by means of seasonal scale simulations by RegCM3 and wavelet decomposition technique for the case of East Asian summer monsoon in 1998. The results show that the lower-frequency precipitation oscillation can be reproduced well by the model, but the higher-frequency oscillations cannot be simulated well, especially for the oscillation with 2-day and 8-day periods. The model gives a cooler temperature all over the troposphere, which is mainly caused by the simulated lower-frequency colder temperature. Besides, the simulated error for temoerature in lower troposphere is caused by the simulation error with high-frequency, which is possibly due to the failure of simulation of diurnal temperature variation associated with the land-atmosphere interaction. The lower-frequency temperature error covers the main portion in the upper troposphere, and it is important to improve the ability of the model in describing the lower-frequency temperature for the whole troposphere. The temperature oscillation with all timescales is not corresponding to that of precipitation during the Mei-Yu period in general, but the oscillation of vorticity is basically coincided with that of precipitation, except for that with the 8-day period. The concentration period for precipitation during the Mei-Yu period is mainly composed of the oscillation with timescale longer that 16 days and shorter than 4 days, and the oscillation with the 8-day period contributes less to the precipitation during the Mei-Yu period. For the correlation coefficient, however, the longer the oscillation time-scale for vorticity, the more the variation of the correlation coefficients in vertical, and the variance contribution rate is almost the same for oscillation of vorticity among all timescales.