Evaluating Land Surface Processes on Simulated Dust Emissions, Air Quality Impacts, and Aerosol–Radiation Interactions

Frequent dust emissions from the Sahara and Sahel during the summer in North Africa can be driven by cold pool outflows associated with moist convection, low level jets, cyclonic/anticyclonic systems, and thermal lows. The precipitation associated with these events can increase soil moisture conditions and in turn vegetation coverage over deserts, which impacts the strength of dust emissions. It is important to simulate realistic dust emissions from this region as the dust aerosols can have substantial impacts on air quality, radiation, and clouds across North Africa as well as regions throughout the globe when transported long distances. Thus, this study proposes to examine the impacts of soil moisture and vegetation on dust emissions, along with impacts on air quality and radiation in the atmosphere, by conducting Weather Research and Forecasting with Chemistry (WRF-Chem) model simulations for the June, July, August dust season over North Africa. Our control (CTRL) simulations will utilize Global Forecast System (GFS) reanalysis data for initial and lateral meteorological conditions. Our experimental (EXP) runs will update the GFS soil moisture fields with NASA Land Information System (LIS) product. Our EXP simulations will also have an updated green vegetation fraction from the 16 day Moderate Resolution Imaging Spectroradiometer (MODIS) product. We anticipate the EXP simulations will lead to more realistic dust emissions transport processes and, consequently, improved air quality forecasts and aerosol-radiation interactions downwind of the dust source regions. Numerous satellite and ground-based data sets will be utilized for the validation including the high-quality aerosol measurements from the Aerosol Robotic Network (AERONET), detailed vertical distributions of aerosols from Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), and shortwave and longwave radiances from the Clouds and Earth’s Radiant Energy System (CERES).