利用SeaWiFS资料反演我国海域气溶胶粒子密度分布

Retrieval of the columnar aerosol grain density from SeaWiFS over the China seas

在卫星数据反演气溶胶光学厚度产品的基础上，讨论了二次反演大气柱中气溶胶粒子密度的问题．通过理论分析，利用多波段气溶胶光学厚度提取大气柱中气溶胶粒子密度是可行的，并指出能否准确确定多波段气溶胶光学厚度会直接影响粒子密度的反演结果．定义并分析了气溶胶粒子消光体积权重系数随粒子半径的变化，表明从气溶胶光学厚度中反演大气柱中气溶胶积聚模态和粗模态粒子密度的结果是可信的．利用SeaWiFS气溶胶光学厚度产品，运用蒙特卡罗法反演了2002年我国海域上空大气柱中积聚模态和粗模态气溶胶粒子密度，结果表明，积聚模态粒子密度比粗模态的高2～3个量级，它们的空间分布趋势一致；我国近岸海域大气柱中气溶胶粒子密度高于离岸海域的；春季气溶胶粒子密度高于其他季节的，特别在黄海、东海海区是如此．

The problem of secondarily-deriving the columnar aerosol grain density from a satellite-retrieved aerosol optical thickness is discussed. It is feasible to retrieve the columnar aerosol grain density with the multi-wavelength aerosol optical thickness. The reliability of the multi-wavelength aerosol optical thickness directly affects the retrieved colunmar aerosol grain density. The aerosol grain-size extinction weighting coefficient is proposed and the variety of the grain-size extinction weighting coefficient with the particle radius indicates that the retrieval of the aerosol columnar grain distribution in an accumulation mode and a coarse mode is believable. Lastly, using the Monte-Carlo simulation method,the columnar aerosol grain density in the accumulation mode and the coarse mode was extracted from the Sea WiFS-retrieved aerosol optical thickness over the China seas in 2002. The results show that the columnar aerosol grain density in the accumulation mode is higher two or three levels than that in the coarse mode, and their distribution has the similar trend over the China seas. The columnar aerosol grain density over the coast is always higher than over the ocean. It is the highest in spring,especially over the Huanghai Sea and the East China Sea.