Influence of relative humidity on optical properties of atmospheric aerosol particles

The optical properties of water-soluble, sea salt (acc. mode), sea salt (coa. mode) and sulfate droplets are simulated at red band and infrared band. The asymmetry parameter, extinction coefficient, scattering coefficient, absorption coefficient and single scattering albedo are performed to study the influence of the relative humidity and wavelength. Comparing the optical properties of the four aerosols in different wavelengths and relative humidity. The difference of optical properties have close relationship with the relative humidity and the wavelength. The differences of five optical properties show an obvious change at special wavelength and relative humidity. And this article also analysis the reasons that generated differences. When the wavelength is nearly 3um, the optical properties have the biggest differences. The optical properties increases with the increasing of the relative humidity, except sea salt. Results show that the influences of aerosol optical properties under relative humility changed from 0% to 99% on the red band and infrared band. The biggest difference of asymmetry parameter reach 33.76% averagely, extinction coefficient is 95.50%, scattering coefficient is 96.47%, absorption coefficient is 90.38% and single scattering albedo is 20.05%. The relative humility could lead to a large change of the optical properties. This research has scientific significance for studying the atmospheric radiation transmission.