Characteristics Of Aerosol Optical Properties And Its Seasonal Variation And Spatial Distribution Over The Eastern China Seas

Atmospheric aerosols play an important role on satellite remote sensing. Research on the spatial/temporal variation of aerosols over the Eastern China Seas can provide references for developing retrieval algorithms for ocean color remote sensing suitable for the local area.In this dissertation, ship-borne observations of aerosol optical properties from5cruise in the Eastern China Seas during2006and2007were analyzed. They were used to investigate the characteristics of aerosol optical depth, single scattering albedo, aerosol size distribution and phase function in different weather conditions. After validation with in-situ observations, the MODIS-derived satellite remote sensing products of aerosol optical depth at869nm during2006and2007were used to study its spatial distribution and seasonal variation over the Eastern China Seas.Analysis of the in-situ observations, we found:the aerosol optical properties have different features in different weather conditions. Over the Yellow Sea, the aerosols optical depths show minimum value in sunny weather, and get larger in dust or haze. Due to the influence of dust and continental pollutants in the atmosphere, the aerosols show strong absorptions over the observation stations in spring, autumn and winter. And the intensity of aerosol absorption is approximately inverse proportional to the distance of the observation site to the coast. The aerosol particle size distributions, especially the ratios of amounts of coarse-mode and fine-mode particles change very frequently. The stations with high aerosol optical depth and strong absorption were dominated by coarse mode particles. Over the East Sea, there are more foggy days in winter, and the aerosol optical depths became higher than in sunny days. Also the fraction of coarse-mode particle is higher in foggy days than in sunny days. The stations near the coast show strong absorption in all wavelengths, due to the influence of atmospheric pollutants from land.Investigation of the spatial and temporal variations of the aerosol optical depth derived from satellite remote sensing, we found:the time-averaged aerosol optical depth has high value at the mid-latitude over the Eastern China Seas. Due to the influence of the terrestrial material in the atmosphere, inshore aerosols optical depth is greater than offshore one. And the aerosol optical depth has a linear decrease trend with the increase of distance to the coast. Due to the influence of dust and monsoon, temporal and spatial distributions of the aerosol optical depth are present in the Eastern China Seas. In spring, the influence of dust makes aerosol optical depth reaching maximum of0.12in the year over the whole Eastern China Seas, especially over the East Sea. The aerosol optical depths begin to decrease during summer and autumn, then increase slowly in winter season.