Assimilation of Satellite-derived Aerosol Optical Thickness and Online Integration of Aerosol Radiative Effects in a Mesoscale Model

To investigate the importance of aerosol radiative effect in the atmosphere, numerical simulation of a dust event during the Puerto Rico Dust Experiment (PRIDE) is presented by using the Colorado State University (CSU) Regional Atmospheric Modeling System (RAMS). Through assimilation of aerosol optical thickness (AOT) retrieved from a geostationary satellite, spatial and temporal aerosol distribution is optimally characterized during the simulation, which facilitates the accurate estimation of aerosol radiative effects. Radiative effect of dust aerosols is considered using different types of radiative transfer. Comparisons against observations show that a direct online consideration of aerosol radiative effects produces the best results. Numerical simulations show that for the atmospheric dust loading considered in this study, the uncertainty in the simulated AOT is 0.05 (10%) and the surface energy balance is different by 40 ∼ 60 Wm−2 if the aerosol radiative effects are not properly represented. The dust radiative effect on the 2m air temperature and atmospheric heating rate are quantitatively analyzed. The results from this study demonstrate that the assimilation of satellite aerosol retrievals not only improves the aerosol forecasts but also has the potential to reduce the uncertainties in modeling the surface energy budget and other associated atmospheric processes