Analysis of the Characteristics of Aerosol Scattering Coefficient at Shangdianzi Background Station
上甸子本底站气溶胶散射系数变化特征的初步分析

The aerosol scattering coefficient(σ_(sp))data observed at Shangdianzi atmospheric background station from 2004 to 2006 have been used to analyze the characteristics of aerosol in the background region.The results show that the mean annual σ_(sp) was relatively low with a slight increase in 2006,which is specially caused by frequent dust pollutions happening during the spring.Diurnal change has a dropping trend in the daytime and a rising trend at night,which accords with the daily change of atmospheric stratification.Seasonally,the values of σ_(sp) in winter and spring were lower than that in summer and autumn.Moreover,weather impacts aerosol obviously.The mean σ_(sp) in sunny days was much lower than that in cloudy condition,due to the strong convection that can increase the aerosol diffusion in sunny days.The air from east-northeast east was clean,which could decrease σ_(sp),while sourh-west wind could bring more polluted air and cause the increase in σ_(sp),which shows that the city activities had an effect on the atmosphere at the observing site.Finally,the background value was calculated through the most frequent statis-tics value,which was in the range of 10-20 Mm~(-1).