Research On The Characteristics Of Aerosol Size Distribution And Complex Refractive Index In Typical Areas Of China

The influence of the atmospheric aerosols,due to its complicated mechanism and the important role in the climate,has become one of the current research hotspots.Atmospheric aerosol particles distribution and the complex refractive index m(m=nr-ini,nr is refractive index real component,ni is the refractive index imaginary part)is an important physical parameter of aerosols.Because of China's vast territory,complicated terrain and climate,the difference between different regions of aerosol source is very big,so the research on aerosol optical parameters of typical region features,especially the complex refractive index of aerosol,is very meaningful.Based on Mie scattering theory combined with the OPC-06 optical particle counter,black carbon,integral turbidity meter and visibility meter instruments,the surface measurement of aerosol physical and optical properties is performed to retrieve atmospheric aerosol complex refractive index of Xinjiang,Tianjin,Xiamen and Hefei four typical areas,and the absorption and scattering coefficient and the aerosol particle number concentration distribution four typical areas is analyzed.In addition,this paper is focus on using the OPC-06 optical particle counter measure aerosol particle number concentration spectrum and using logarithmic normal distribution to fit number concentration distribution of urban,mainland,desert and marine aerosols,and then analyzing their characteristics.Main conclusions are as follows:(1)Spectral distribution of aerosols in Tianjin area,Xiamen area,and Hefei area is described by Junge distribution and lognormal distribution,in which the modal are lognormal distribution,the peak is centered in 0.80,0.86 and 0.54 um,and this accords with the characteristics of urban aerosols;the Xinjiang region of aerosol spectral distribution is described by Junge distribution.(2)The atmospheric aerosol real part nr of refractive index in Xinjiang area,Tianjin area,Xiamen area,and Hefei area is around 1.50,the refractive index imaginary part ni of that is 0.010,0.017,0.008 and 0.016 respectively.(3)The extinction coefficient and absorption coefficient in Tianjin area,Hefei area and Xiamen area are in good agreement with the change of wavelength.In the long wave band,there is almost no change;In the Xinjiang region,extinction effect in short-wave band,and absorption effect in the long wave band are significant respectively.(4)The number concentration distributions of the urban aerosols,the rural aerosols,the desert aerosols,and marine aerosols are basically all overlaid by logarithmic normal distribution in three sections.Urban aerosol's middle modal radius is around 1 microns.Rural aerosol and desert aerosol mainly has two fine grained modal,and rural aerosol's particle concentration is low.Marine aerosol's middle modal radius is also near 1 um,which is mainly consist of the sea salt droplet.There is no coarse mode in the Pacific Ocean,the concentration of desert aerosol's coarse mode the largest in the summer.