太湖地区大气气溶胶光学及微物理特征分析

Analyses on Aerosol Optical and Microphysical Properties over Taihu Lake Region

利用2005年9月-2008年6月AERONET太湖站的Level 2.0数据,分析了该地区光学厚度随波长的变化趋势。结果表明,在双对数坐标中太湖光学厚度随波长变化的曲线并非直线,可用二次多项式拟合,气溶胶粒子符合对数正态谱分布。单次散射反照率SSA的变化表明,冬季SSA值较小;春季SSA随波长增大而增大,8、9月SSA随波长增大而减小。2005年9月—2006年11月太湖站粒子谱和粒子体积浓度变化表明,春季粗粒子体积浓度约是细粒子的2倍～2.5倍;总粒子体积浓度受粗粒子影响出现峰值;夏末及初秋细粒子的体积浓度要明显大于粗粒子的。春季粒径<3μm的粗粒子增加量比粒径>3μm的粗粒子增加量要大,因而粗粒子有效半径减小。最后分析了2006年4月16～18日北方沙尘天气对太湖地区气溶胶微物理参数的影响。

Using Level 2.0 data of AERONET Taihu station,change of the Aerosol Optical Depth（AOD） with wavelength is analyzed.The results indicate that the curve is not linear at the double logarithm coordinate,but it can be fitted well with quadratic polynomial.Aerosol particles consistent with lognormal size distribution.the single-scattering albedo（SSA） is investigated also.SSA is relatively small in winter.When the wavelength get longer,SSA increases in spring but decreases in August and September.Additionally,the particle spectra and volume concentration from September 2005 to November 2006 are analyzed.In spring,the volumetric concentration of coarse particles are 2.0~2.5 times that of fine particles;and total particle concentration,affected by the coarse one,appears a peak.In the late summer and early autumn,however,the situation is in reverse.Increasing amount of smaller coarse particles（3 μm） is larger than that of bigger particles（3 μm） during spring,which induces the diminishment of coarse particles effective radius.Finally,a dust weather process influence on the aerosol micro-physical parameters during 16~18 April 2006 are analyzed.