中文摘要：

利用美国大气研究中心（NCAR）的公用气候系统模式（CCSM2．01）进行了一组改变青藏高原地形高度和地球轨道（岁差）参数的数值模拟试验，以探讨青藏地区地球轨道和地形变化对高原气候的影响。结果表明：同样的岁差强迫，青藏地区与湿度相关的各种气候要素（如降水、地表径流、降雪和积雪深度）在高地形情况下的响应要比在低地形情况下的响应强烈得多。当近日点的时间由现代的1月份变为7月份时（如距今约1万年前的全新世初期），会造成高原中南部及高原南侧夏季降水和径流显著增加，冬季高原西北部降雪增加，但高原中南部的冬季降雪却会明显减少。上述区域气候变化特征与岁差强迫下大气环流的改变密切相关。这些数值模拟结果也有助于理解该地区相关地质气候记录中青藏高原隆升过程对轨道尺度气候变率的调制作用。

英文摘要：

Using the National Center for Atmospheric Research （NCAR） Community Climate System Model （CCSM 2.01）, a set of numerical experiments were conducted to examine dependence of the orbitalscale climate variability over the Qinghai Xizang Plateau region on the orography by changing the plateau topography and the Earth＇s orbital parameter （precession）. The result shows that the response of climatic elements related to the humidity （such as precipitation, runoff, snowfall and snowdepth） is much stronger in a high-orography case than in a low-orography case to the same precession forcing. When the date of perihelion is changed to January from July, the summer precipitation and runoff increase significantly in the mid-south part of the Qinghai-Xizang Plateau. Meanwhile, winter＇s snowfall and snowdepth increase in the west north part but decrease in the mid-south part of the Qinghai-Xizang Plateau. The above climatic variations are found to be related with changes in the atmosphere circulation induced by the precession. These modeling results may be helpful to understand the modulation of the uplift of the Qinghai-Xizang Plateau to the regional climate variability reflected by relevant geological records.