Sensitivity experiments of regional radiative forcing due to dust aerosol under clear sky condition

摘要

Numerical sensitivity experiments to evaluate the impacts of optical characteristics on the radiative forcing have been performed in this study. The experiments involve in the effects of refractive indices, single scattering albedo, asymmetry factor and optical depth. An updated data set of refractive indices representing East Asian dust and the data set recommended by World Meteorology Organization are used in our calculations. A k-distribution model for solar and thermal radiation transfer is employed. Studies show that comparing with WMO dust model, East Asian dust model has stronger scattering and weaker absorption at solar regime, which leads to higher negative forcing at the top of atmosphere (TOA). The more important is the signs of radiative forcing at TOA over desert regions could be reversed for the two dust models, which emphasizes the essentiality of accurate measurements of optical properties of dust aerosols for accurate estimating of radiative forcing