The Influence of Simulated Surface Dust Lofting Erodible Fraction on Radiative Forcing

Abstract. The use of dust erodible fraction geographical databases in case-study numerical simulations provides more realistic dust loading compared to idealized, non-spatially-constrained methods. Idealized lofting in case study scenarios tends to generate unrealistically large amounts of dust compared to observations, due to the lack of locational constraints. Generally, simulations of enhanced dust mass via surface lofting lead to reductions in daytime insolation due to aerosol scattering effects, as well as reductions in nighttime radiative cooling due to aerosol absorption effects. In simulations with extreme dust concentrations, these effects noticeably suppress the model environment’s diurnal temperature range. In simulations with lesser amounts of lofted dust, the presence of dust is shown to still strongly impact the radiative fluxes while only marginally modifying the low-level temperature. Increased resolution in dust erodible fraction inventories are shown to enhance the details of dust lofting locations and potential, thereby, mitigate over-lofting and associated radiative response biases over regions that are unlikely source locations.