THE IMPACT OF RELATIVE HUMIDITY ON THE RADIATIVE PROPERTY AND RADIATIVE FORCING OF SULFATE AEROSOL^*

With the data of complex refractive index of sulfate aerosol,the radiative properties of the aerosol under 8 relative humidity conditions are calculated in this paper.By using the concentration distribution from two CTM models and LASG GOALS/AGCM,the radiative forcing due to hygroscopic sulfate aerosol is simulated.The results show that:(1)With the increase of relative humidity,the mass extinction coefficiency factor decreases in the shortwave spectrum;single scattering albedo keeps unchanged except for a little increase in longwave spectrum,and asymmetry factor increases in whole spectrum.(2)Larger differences occur in radiative forcingsimulated by using two CTM data,and the global mean forcing is -0.268 and -0.816 W/m2,respectively.(3)When the impact of relative humidity on radiative property is taken into account,the distribution pattern of radiative forcing due to the wet particles is very similar to that of dry sulfate,but the forcing value decreases by 60%.