Study On The Complex Refractive Index Of Aerosol And Radiative Effects

Atmospheric aerosol is a system which include atmospheric medium and the solid or liquid particles mix in it.Due to it can absorb and scatter solar short-wave radiation and earth long-wave radiation(direct radiation force),the atmospheric aerosol have influence on the radiation balance of earth-atmosphere system,so it can be used as a radiation chatacteristics of the condensation nuclei which effect the cloud and the reaction surface which effect the chemical reaction speed(indirect radiation force),the atmospheric aerosol occupy an important position in the reasrch of atmospheric radiation and climate change, the inversion of atmospheric aerosol optical thickness palys an important role in the atmospheric correction.The complex refractive index of atmospheric aerosol particles determines the different scattering and absorption properties of the solar and long-wave radiation,the real part of the refractive index determines the scattering properties and the imaginary part determines the absorption properties which plays an important role in the atmospheric radiation balance.Aerosol optical properties and its radiation effect is a hot issue in the field of global climate change research.This study introduce how to get the corresponding radiation optical parameters (scattering coefficient, absorption coefficient, transmittance and single scatteing albedo, asymmetric factor, scattering phase function, etc) form the real part and imaginary part of different kinds of aerosol particles refractive index in the infrared longer wave-length range(4-10um).The complex refractive index of different types of aerosol particles in spectrum change with the wavelength,according to the real part and imaginary part of different kind aerosol refractive index to calculate the correspongding radiation optical parameters using aerosol mixing and hybird method and obtain the corresponding radiative forcing using the atmospheric radiative transfer model SBDART.And analyze the optical characteristics of aerosol particles scattering and absorption of radiation effects. The main conclusions are as follows:(1) Through atmospheric radiative transfer model SBDART calculated the surface, the top of atmosphere and atmospheric radiation force under the certain conditiongs.It shows that as the imaginary part of complex refractive index of aerosol and the surface is much larger; As the real part of complex refractive index of aerosol and radiation force on the top of the atmosphere is larger,too. And the top of the atmosphere radiative forcing changes with respect to small changes in the surface, the imaginary part of the aerosol complex refractive index of the contribution of long-wave radiation.(2) By inversion of aerosol optical thickness of the Taihu Lake region, combined with SBDART calculated under different aerosol optical depth irradiance and aerosol factor caused by the direct radiative forcing. Compared with AERONET on Taihu Lake Station and it is reasonable. It shows that the effects of aerosol optical thickness on direct radiation forcing is large. Aerosol optical depth increases, the smaller the net radiation flux. It leads to the surface and the top of atmosphere radiative forcing increases.(3) By calculating the aerosol radiative forcing under changing the complex refractive index of the imaginary part on the same aerosol optical thickness and of the real part. It shows that aerosol radiative forcing is related to the aerosol single scattering albedo and the asymmetry factor. Aerosol single scattering albedo increases, the smaller the surface and the top the top of atmosphere radiative forcing. On the same conditions the asymmetry factor increases, the larger the surface and the top the top of atmosphere radiative forcing.