| Dust aerosols, as a most important component of aerosols in the atmosphere, can modulate global and local balance of radiation energy impact and thus forcing climate change effects. The dust aerosols, blown up by strong wind, could harm the natural environment and human activities. Therefore, it is necessary to research dust aerosol and its radiation forcing effects; But also on the occurrence of sandstorms forecast, early warning is important to dust hazards. In this paper, Using Lanzhou university semi-arid climate and environmental observatory (SACOL) in March 2007 27-29, the process of a strong dust variety of observation data and HYSPLIT - 4 model and the MODIS satellite remote sensing image about the process of a preliminary analysis. Application WRF-CHEM model, NCEP analysis data as the initial field and the boundary conditions by using three nested, for the simulation of the dust process and dust aerosol direct radiation effect of the radiation and the resulting feedback on the surface meteorological elements and atmospheric fields are preliminarily analyzed.(1) Ground in the dust before the arrival of more control for the northwest wind, and there will be a wind speed from 4m/s increased to 8m/s, relatively dry air at 10% relative humidity near the base. During dust process, PM10 concentration and the trace gases NO2, NOx, SO2 concentration are in the opposite trend, indicating that the dust events and the different man-made pollution incidents, and the impact of dust weather conditions and the diffusion of trace gases generated. The influence on the ground by the dust of shortwave radiation received the maximum difference could reach 200 W m-2.(2) Dust occurs in a certain large scale background field, There are obvious high-altitude frontal zone and the upper existing jet, The ground cold high pressure at altitude northwest airflow under the direction of movement, Advection of cold high altitude made the further development of surface cold high pressure. The dust generation needed to have high and low temperature, require high temperature-pressure field configuration.(3) HYSPLIT-4 model to the dust during the post-flow to the track. the dust from the lower there are two main sources of areas:a source close to the Tibetan plateau in Qinghai, Another source is the Taklimakan Desert in Xinjiang. The high-level northwest flow of weather map is more consistent.(4) Compared before and after the MODIS visible satellite image of dust can be drawn:Before the dust arrival the image can clearly reflect the surface conditions, the dust affecting surface conditions is fuzzy. The difference between dust and clouds the dust with the topography and is spread along the topography,but height of high clouds as less affected by terrain.(5) WRF-CHEM model by two different sand flux calculation scheme Modell and Model 2. The results show that:Model 1 can better reflect the basic characteristics of the dust process.700hPa PM10 concentration variation of the same ground only a small concentration. Largely consistent with the change in the boundary layer, Small is the concentration of deposition and diffusion; 500hPa PM10 concentration in the former two have different characteristics and have two peaks:The first peak may be combined with high-level wind strength is greater than the lower speed and may be the source of long-distance transmission of high-level results, The second peak could be the role of low-level dust up the results of transmission.(6)The two groups Numerical simulation experiment control experiment (CTL) and short wave radiation feedback dust experiment (RAD) of the results can be seen, Judging from time to change the most dust makes 2m temperature cooling about 2℃Short wave radiation more than 200 Wm-2 reduction, The sensible heat flux reduce up to 100 Wm-2. PM10 concentration in terms of space determines the distribution of meteorological elements and their field of meteorological effect, PM10 concentrations of high value corresponds to 2m temperature and sensible heat flux difference between the maximum area, Changes in the concentration of the center and with two high values also will move the change.
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