With the help of the two vegetation database, a regional climate model and a global climate model were used to simulate the effect of land cover change on climate of the past 300 years(1700 ～ 1995)in China. The regional model used in this study is RegCM3 developed from the NCAR first version of regional model by the Abdus Salam International Center for Theoretical Physics in 2003 ～ 2004. In RegCM3 the large scale cloud parameterization,cumulus convective parameterization, and sea surface flux parameterization are modified. RegCM3 is one of the popular regional climate models in climate modeling. The Global model used is AGCM+SSiB,which is the third version of IAP nine-level GCM plus improved land surface processes. These two models have different roles in climate simulation. The global model can give responses of climate to vegetation change on global scale, while the regional model can show more detailed dynamical structures when land cover changes. For the global model, the historical land cover change during 1700 ～ 1990 from HYDE V2.0 are used in simulations,and reconstructed regional vegetation from historical documents of China during 1724 ～ 1995 is used in RegCM3. The simulations from global and regional climate models with different vegetation types in historical times are analyzed to detect the potential effects of land cover change on the regional climate of China. The modeling results by these two models show that the natural vegetation deterioration duo to the expanding of crop land might have significant effects on regional climate. Through comparative analyses of surface temperature, summer precipitation and low atmospheric circulation in different land covers and in different times, it is found that the annual mean temperature had some decrease and obvious seasonal difference after the natural vegetation was replaced by crop land, especially in East China. In vegetation deteriorated regions increase in summer temperature and decrease in winter temperature were universal. Moreover, the summer precipitation had significant decrease. The 850hPa wind field also had obvious change. The significant decrease in summer precipitation might be related to the enhanced lower anti-cyclonic circulation. It means that the deteriorated vegetation due to land use would weaken the summer monsoon circulation in the past 300 years. Therefore,the land use change might be a potential cause of weakening of the East Asian monsoon.%以两种植被数据为基础,分别利用区域和全球气候模式对过去300年土地利用和地表覆盖变化的气候效应进行了模拟研究.结果表明,耕地面积不断扩大所造成的自然植被破坏可能对区域性气候产生显著影响.通过对不同时期植被特征下地面温度、降水和低层大气环流的比较分析发现,中国东部地区耕地取代自然植被后,全年平均温度有所降低,且存在明显季节差异.植被退化地区的夏季温度有明显升高而冬季温度则显著降低;同时夏季降水和850 hPa风场发生显著变化:夏季降水明显减少,而这一结果与低层(850hPa)大气环流的反气旋性增强相联系,即植被退化使中国东部夏季风环流减弱,这与目前观测事实是一致的.土地利用引起的地表覆盖的变化可能是东亚季风减弱的原因之一.
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