Direct Radiative Forcing by Dust in China Based on Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) Datasets

Large uncertainties exist in simulated direct radiative forcing by dust in climate models.Multi-model comparisons quantify the range of uncertainties in current climate models.The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) is set up to evaluate the radiative forcing and climate effect of short-lived chemical species in the atmosphere.Based on simulated dust concentrations from 7 ACCMIP models,we quantify in this work the direct radiative forcing by dust in China and the range of uncertainties.Our results show that annual total emission,annual mean surface-layer concentration,burden,and AOD (Aerosol Optical Depth) of dust averaged over China are 215±163 Tg a^-1,41±27 μg m^-3,9±4 kg m^-2,and 0.09±0.05,respectively.Simulated annual mean short-wave,long-wave,and net (short-wave plus long-wave) direct radiative forcings by dust averaged over China are,respectively,-1.3±0.8 W m^-2,0.7±0.4 W m^-2,and -0.5±0.7 W m^-2 at the top of the atmosphere and -1.5±1.0 W m^-2,1.8±0.9 W m^-2,0.2±0.2 W m^-2 at the surface.Long-wave radiative forcing by dust is found sensitive to vertical distribution of dust concentrations.Dust aerosol in high altitudes contributes largely to long-wave radiative forcing at the top of the atmosphere.However,short-wave radiative forcing by dust is dependent on dust burden but not sensitive to its vertical distribution.