An Observation Study Of Aerosol Scattering And Related Properties In Northern Suburb Of Nanjing

The industrial pollution over northern suburbs of Nanjing is heavy. The aerosol optical properties were continuously observed by Integrating Nephelometer, Micro-pulse Lidar and Particulate Matter Monitor from June2010to April2011in NUIST (Nanjing University of Information Science&Technology). In this study we analyzed the variation characteristics of aerosol scattering coefficient, the vertical distribution of aerosol extinction coefficient and the relationship between scattering coefficient and mass concentration. The results showed as follow:(1) The scattering coefficient was significant changed in different observation day, and the average scattering coefficient of550nm wavelength for whole experiment period was343.58Mm-1, with the standard deviation of234.36Mm-1, about70%of the scattering coefficient in the range100-400Mm-1. Affected by human activities and atmospheric stratification, scattering coefficient is high in the daytime and low in nigh. With the season changed, the peak of the value was slightly different and the average value of four seasons was summer> spring> autumn> winter. The Angstrom exponent changed from0.92to2.09, while the back-scattering ratio showed an increase trend from0.09-0.19, which indicated fine particles content increases in the observation period.(2) The aerosol scattering coefficient increased dramatically when the wind flows were from southeast with2m/s speed, while low scattering coefficient values often appeared in the periods of western wind. In general, the scattering coefficient increased with relative humidity increased, but due to the serious pollution, the impact of humidity on the scattering coefficient is not so significant.(3) A good relationship between scattering coefficient and PM2.5mass concentration was found with high correlation coefficient as0.93. PM2.5mass scattering coefficient changed in the range of0.17-4.63m2/g, an average value was1.87m2/g. The correlation between aerosol scattering coefficients and visibility was-0.66described by a negative power function.(4) The vertical distribution of aerosol extinction coefficient increased with increasing height from0-1km, and then decrease. The maximum is about several km-1, usually appeared in the position less than1km, and the minimum appeared at the height of6km, only10-3km-1. The vertical extinction coefficient is influenced by the development of the boundary layer, showed that upslope value appeared during the day and dissipated at night.