| Climate change has raised the concern of the current governments and scientific community. However, the past and future climate simulations are considered uncertainly with the lack of awareness and knowledge. Most of the solar radiation to the earth makes the climate effects through clouds in climate system, which also plays a strong regulatory role of the radiation effect to the entire earth-atmosphere system. Direct climate effects of clouds has been understood more clearly, however, the radiation characteristics of cloud depends not only on its distribution, but also on cloud cover, optical thickness, cloud water path, effective radius and other cloud microphysical properties, then these factors would indirectly affect on climate. This paper would contain the following two main research contents.Firstly,the temporal and spatial characteristics of cloud over China have been analyzed using the ISCCP (International Satellite Cloud Climatology Project) monthly mean D2 data from July 1983 to June 2005 and MODIS ( MODerate-resolution Imaging Spectro-radiometer) monthly mean MOD06 data from 2000 March to 2009 June. The results show that: (1) over the past 20 years, total cloud amount has little change in trend in most parts of China; in the South China and the northwest of China, the total cloud amount over there is in an increased trend, while it has been decreased trend in the central part of Qinghai-Tibet Plateau. (2) It is also found that the total cloud amount in different seasons has different trend. The changes in cloud effective radius have the greatest effect to the cloud optical thickness during summer, which means that aerosol indirect climatic effect may be the strongest during summer. The changes of cloud optical thickness and effective radius also show that the cloud over the Yangtze River region and the Qinghai-Tibet Plateau region may be caused prominently by aerosol indirect climatic effects. (3) Besides, the ice cloud optical thickness and effective diameter are associated with strong regional characteristics in China, indicating that the ice cloud micro-physical mechanism is more complex than the water cloud.Secondly, with the previous work, the CAM3.0 model we used is based on comparison of two internationally advanced models, one of which is the NCAR/UCAR joint development of new generation atmospheric general circulation models Community Atmospheric Model3.0 (CAM3.0), and the other is the Canadian Aerosol Module Canadian Aerosol Module (CAM) for one-way online interaction. The model has also used the theory of Hayder Abhul-Razzak et al. which provides the aerosol activation progress, as Aerosols-Climate coupled model simulation, and it uses AeroCom 2009 pollution source data. By CAM3.0 model simulation from January 1, 1980 to December 30, 1996, the later 10 years data has been analyzed and several major conclusions have been drawn, with the comparisons to the satellite data.(1) Model can simulate the global total cloud amount of seasonal and annual distribution, especially over the equatorial region and marine region. The simulation of the global distribution of high cloud reflects the basic reality; in the equatorial and low latitude regions, the simulated valu is lager than the satellite data, while in the polarization it is smaller. The simulation of the middle cloud amount global distribution approaches the observations, but larger deviations in the Polar Regions. The best Model analysis is the simulation of the total cloud amount.(2) Model simulated total cloud amount distribution in China is similar to the observations, but the valu is lower; model simulated high cloud amount distribution in China basically reflects the distribution of reality, but the value is higher than observation, especially in Tibetan Plateau; model simulated the distribution of middle cloud amount in China are quite different from observations, mainly in the Tibetan Plateau. |
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