A Preliminary Study On The Properties Of Atmospheric Aerosols In Qingdao

Aerosol has much influence on the earth-atmosphere climate system through its impact on direct and indirect radiative forcing. It also plays a crucial role in regional air pollution problems.Lying on the south of Shandong peninsula and surrounded by the sea, the aerosol in Qingdao area is affected by land and ocean. Based on direct and scattered radiation data measured by Skyradiometer, TSP (total suspended particulate) and size segregated data, and the Moderate Resolution Imaging Spectroradiometer (MODIS) data, the optical property and spectrum distribution of aerosol and the effects of meteorological situation are analyzed in Qingdao area. The aerosol optical depth (AOD) measured based on MODIS and on ground are compared. The results show that:Caused by meteorological situation, daily variance of AOD is rather large in Qingdao area. South wind increases AOD and its daily range. Light fog and haze have rather large proportion in AOD, and the contribution of fog is larger than that of haze. For the wavelength shorter than 500nm, the single scattering albedo (SSA) is higher in summer and lower in spring. But the SSA is higher in spring for the wavelength longer than l000nm. With the wavelength increases, the scattering ability of aerosol descends. The wavelength index ranges from 0.9 to 1.4, and turbidity is lower than 0.3 in Qingdao area.In the surface layer, the concentration of coarse particle is highest in spring, and fine particle is about three times in winter to other seasons. The coefficient of correlation between AOD and volume concentration of accumulated particulate is above 0.9. It means that the particulate of accumulated mode plays leading role in extincting solar radiation. With the wavelength increases, the coefficient of correlation between AOD and nucleus particulate decreases, but the coefficient goes up between AOD and coarse particulate. For the humidity over 60%, with the humility increases, nucleus and accumulated particle manifold.Comparisons between AOD measured by MODIS and by skyradiometer give good correlations. When the AOD is lower than 0.7, the value measured by MODIS is higher than measured by skyradiometer, but when the AOD is higher than 0.7, the reverse shows. The correlation between AOD measured by MODIS and the accumulated particulate is good. But the correlation between AOD by MODIS and the nucleus and coarse particulate are poor.Using MODIS products from NASA, the seasonal characteristics and variation of AOD over Shandong peninsula are analyzed. Combined MODIS data and meteorological data and API data, the effect of two dust storms during 2002 on Qingdao are analyzed. The results show that the dust can be transported from the source area to Qingdao, and debase the local air quality.