中文摘要：

青藏高原隆升对亚洲乃至全球气候演化的影响是古气候学热点问题之一。青藏高原的热力和动力效应一直以来受到人们的广泛重视，其中高原对大气环流的阻碍作用被认为在亚洲冬季气候形成中扮演着极其重要的作用。过去的理论及重建研究大都强调青藏高原主体的贡献，忽略了高原边缘中小尺度地形的可能贡献。以青藏高原北边缘蒙古地形为例，现代大气流场显示蒙古地形对冬季对流层低层西风具有明显的阻碍作用。本研究利用一个海气耦合模式评估了蒙古地形对亚洲冬季气候的影响及其同青藏高原主体的相对贡献。结果显示，蒙古高原地形对亚洲西风急流和东亚冬季风具有非常显著的影响。蒙古高原存在时，东亚大槽加深，日本上空的西风急流增强，东亚冬季风环流也增强。该效应主要源自于亚洲大气热力结构的变化，对流层低层西风在蒙古地形的动力强迫下向北绕流，在下游产生强烈的北风异常，有利于极地冷空气南下。该温度冷平流最终导致西风急流和冬季风环流的响应。值得注意的是，青藏高原主体对西风急流和冬季风的贡献要明显弱于蒙古高原。该结果启示我们，传统认识的青藏高原动力效应可能被一定程度高估，亚洲各地形的动力效应不仅同其规模和高度有关，也与其所处位置有关，处于敏感区域的较小尺度地形同样会对亚洲气候形成有不可忽略的影响。

英文摘要：

The influence of the Tibetan Plateau（TP）uplift on the evolution of Asian climate and global climate is one of the hottest topics in the paleoclimate community. The thermal and dynamical effects of the TP are widely emphasized. The mechanically blocking effect is considered to play a vital role in the formation of Asian climate during winter. However, most theoretical and proxy studies in the past are focused on the contribution of the main body of the TP, the potential contribution of small-scale mountainous topography around the main TP is always neglected. Taking the Mongolian Plateau （MP） as an example, it is located to the north of the main TP. From the perspective of the modern atmospheric circulation observation, the topography of the MP significantly hinders the upwind low-level westerly winds in winter. But its climate effect and mechanism is rarely studied by numerical simulation. In this study, a coupled ocean-atmosphere model is used to simulate the effect of the topography of MP on the Asian climate during winter and its relative contribution is analyzed compared to the main TP. The result shows that the upper troposphere East Asian trough is deepened and the westerly jet over Japan is remarkably strengthened with the topography of the MP in model. Besides, the East Asian winter monsoon circulation is also intensified as the northerly wind in lower troposphere is significantly intensified. The climate effect of the MP to Asian winter is achieved by the change in the atmospheric thermal structure. The strong North Hemisphere westerly winds at lower troposphere in winter are forced to encircle the MP northwards when facing it, which produces a strong northerly wind anomaly over the downwind region. The northerly wind anomaly allows the southward penetration of the cold air from the high latitudes and this cold advection finally leads to the responses of westerly jet and East Asian winter monsoon. Moreover, the contribution of the MP topography on the westerly jet and East Asian winter monsoon is