| Global warming is an undoubted fact demonstrated in the IPCC forth assessment report. Climate changes not only affect human activity, but also influence regional economy and social development. Consequently, global warming becomes a serious problem, which absorbs global view. Mid-Holocene is the most recently warm and humid period, of which the CO2 concentration is similar to that of Pre-industrial, and there are abundant geological records that can be used to study the mid-Holocene climate change, which is a reference to understand the mechanism of global warming.In recent years, climate change in central Asia, eastern monsoon Asia and arid central and eastern Asia has become hot research topic. These three areas are also sensitive to climate change, at the same time, the situation of climate variability is different due to different climate conditions. We investigate the role of insolation forcing and vegetation feedback on the climate during the mid-Holocene (6000 years before present) using results from six coupled ocean-atmosphere-vegetation general circulation models and coupled ocean-atmosphere general circulation models in the Paleoclimate Modeling Intercomparison Project Phase 2 (PMIP2). Here we analyze temperature and precipitation changes compared to pre-industrial (1750 AD) control runs in summer (June to September) at the Mid-Holocene in three areas:1. Central Asia whose climate is affected by South Asian monsoon and Westerly wind; 2. Central and East Asian arid Area is marched with Westerly wind and Asian monsoon; 3. East Asian monsoon Area is mainly influenced by East Asian monsoon. For the different models and the vegetation models used by the different models, there are variations in the mean temperature and precipitation changes (6ka-0ka) across models.The main conclusions of the paper are as follows:The forcing of Earth's orbital parameters during the mid-Holocene using results from six coupled ocean-atmosphere general circulation models plays an important role on the summer temperature. These regions have experienced different degrees of warming due to changes in Earth's orbital parameters, being the major factors that determine climate changes during mid-Holocene.Vegetation is also one of the most important factors that have influence on Mid-Holocene climate change, which is analyzed with the results of six coupled ocean-atmosphere-vegetation general circulation models and with the difference between OAV and OA.In southern Himalaya, all models show significant cooling except ECBILTCLIOVECODE and FOAM which show slightly warming by 1-2℃. Models except ECBILTCLIOVECODE coupled with vegetation intensify the cooling trend. All models show precipitation significantly increased during the mid-Holocene.In the arid central and eastern Asia, model results of ECBILTCLIOVECODE,FOAM and UBRIS-HADCM3M2 show that the increased change in vegetation cover lead to a lower mean summer surface temperature. And results from the rest of the models show that the improved vegetation cover changes lead to a warmer mean summer surface temperature. All models show the mean summer surface temperature is about 0.5℃lower than present in Xinjiang area of Northwest China except MRI-CGCM2.3.4NFA. We conjecture that the increased vegetation cover result in improved leaves albedo, and then the reduced the solar radiation reaching earth surface. In East Asian Monsoon Area, the results show different variations between different models. Results of FOAM,ECHAM5-MPIOM1 and MRI-CGCM2.3.4FA show lower temperature compared to pre-industrial control runs. Results from ECBILTCLIOVECODE,UBRIS-HADCM3M2 and MRI-CGCM2.3.4NFA show that the improved vegetation cover changes lead to a warmer mean summer surface temperature. But the precipitation changes caused by the vegetation cover changes are quite different between different models and the results are not ideal.
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