China In The Eastern Part Of The Aerosol Radiative Forcing And Climate Effect Of Numerical Simulation

Using the aerosol optical depth product retrieved by MODIS, we analyzed the spatial and temporal characteristics of aerosols over the middle eastern China in 2001. The aerosol optical depth has the obviously seasonal change characteristics. The maximal values of aerosols were found in the Sichuan basin and the middle and lower reaches of Yangtse River for the whole year. On the base of it, Using the Fifth-Generation of PSU/NCAR Mesoscale Model (MM5 ) , we firstly simulated the spatial and temporal characteristics of sulfate aerosols direct radiative forcing and climate effects during clear sky over middle eastern China, then developed the sensible experiments for the sulfate aerosols direct radiative forcing and climate effects when doubling the aerosol optical depth and selected six small areas to compare the difference of the surface temperature. The results are as follows: During clear sky, the aerosol radiative forcing is consistent with optical depth in the position. There is a good exponential relation between radiative forcing and optical depth. The surface temperature responses are obviously regional and seasonal dependence. After doubling the aerosol optical depth, the distribution of clear radiative forcing change is coherent with the case of one, but each season has different change range. With the regional average, the largest direct radiative forcing during clear sky is in spring reaching -34.53W/m2 in the case of one and -59.25 W/m2 in the case of two; the smallest one is in summer respectively reaching -20W/m2 and -34.18 W/m2 in the case of one and two over middle eastern China. While the largest value of the surface descendant temperature is in winter reaching -0.65℃ in the case of one and -1.1℃ in the case of two; the smallest one is in summer respectively reaching -0.09℃ and -0.18℃ in the case of one and two. The sensitive experiments with single scatter albedo change for the change of radiative forcing , surface shortwave radiative flux, surface temperature and total cloud mount indicate that the radiative forcing on the top of the atmosphere varies less than the surface short wave radiative flux does. During clear sky, the radiative forcing on the top of model increases with the increasement of the single scatter albedo, while the surfaceshortwave radiative flux decreases. With the increasement of the single scatter albedo, the decreasing tend of the surface temperature enlarges. Therefore, it is very significant for understanding the aerosol radiative forcing and surface temperature effects to consider the kinds of aerosols associated with radiative characteristics in detail.