中文摘要：

通过模式结果与实况资料和地质记录对比，表明模式系统可以较好地模拟现代气候状况和末次盛冰期气候的变化，特别是降水的变化与地质记录符合得较好。在末次盛冰期和现代气候状况下地球轨道参数的变化对中国地区年平均温度的影响很小，但对不同季节温度变化的作用不同。冬季气温的变化比较显著，不能忽略。CO2浓度在末次盛冰期最低，其混合比为200×10^-6，这使得气温降低。CO2的作用也存在明显的季节和区域特征。冬季其影响最大；但夏季其作用较小，甚至出现CO2浓度减少温度增加的现象。产生增温现象的原因是云量发生了变化，使到达地面的太阳辐射增加。这个结果表明云在气候变化中，可能起着非常重要的作用，甚至可以影响某时段和区域温度等要素变化的方向。青藏高原地区对这两个辐射因子变化的响应与中国其他地区相比偏小，原因是该地区的云量高于其他地区。相对现代气候，末次盛冰期地球轨道参数变化对气候的影响小于CO2的作用。但相对于末次盛冰期气候的变化，这两个因子的贡献都是比较小的。CO2对末次盛冰期年平均温度变化的贡献大约为3％-10％。此外，现代和末次盛冰期气候背景下，CO2的作用相同。

英文摘要：

Using a regional climate model MM5 nested with an atmospheric global climate model CCM3, a series of simulations and sensitivity experiments have been performed to investigate responses of the present day climate as well as the LGM climate to different mechanisms over China. Model simulations of the present day （PD） and LGM climate changes are in good agreement with the observation data and geologic records, especially in the simulation of precipitation change. Under the conditions of the PD and LGM climate, changes of Earth orbital parameters have little influence on annual mean temperature over China. However, the magnitude of effect shows seasonal pattern, with significant response in winter. Thus, this influence can not be neglected. During the LGM, CO2 concentration reached its lowest point of 200 × 10^-6. This results in a temperature decrease over China. The influences of CO2 concentration on climate show seasonal and regional patterns as well, with significant influence in winter. On the contrary, CO2 concentration has less impact in summer season. In some cases, temperature even increases with decreasing in CO2 concentration. This temperature increase is the consequence of the increase in the solar radiation that reaches the earth＇s surface due to the decrease in cloud amount. This result suggests that cloud amount plays a very important role in climate change and could directly impact the response patterns of some climate variables such as temperature in certain periods and over certain regions. Temperature responses to changes of the above two factors in the Tibetan plateau, are generally weaker than in other regions of China because the cloud amount over the plateau is generally higher than in the other areas. Relative to the PD climate, changes in orbital parameters have less impact on the LGM climate than changes in CO2 concentration. However, both factors have rather small contributions to the climate change in the LGM. About 3 % -10 % changes in annual mean temperature are contributed by ch