7A.1 Evaluation of WRF-Chem cloud-resolving modeling of haboobs

Anisimov, Anatolii, King Abdullah University of Science and Technology (KAUST), Duncan Axisa, National Center for Atmospheric Research (NCAR), Suleiman Mostamandi, KAUST, Paul A. Kucera, NCAR, and Georgiy Stenchikov, KAUST

We combine unique aircraft observations of aerosol and WRF-Chem simulations to investigate mesoscale dust storms in Central Arabian Peninsula caused by cold pool outflows from deep convective clouds ("haboobs"). To simulate dust generation and transport, we configure the WRF-Chem model with the fully interactive 8-bin MOSAIC aerosol microphysics scheme and run it using cloud-resolving grid spacings. We utilize the aerosol aircraft observations near Riyadh in April 2007, obtained during the "Kingdom of Saudi Arabia Assessment of Rainfall Augmentation" research program. The in-situ aircraft observations of dense dust plumes within haboobs are indispensable for assessment of dust properties during periods of extreme loading.

The model captures the main features of convection, producing reasonable precipitation patterns. The simulated aerosol optical depth at the AERONET site locations and large-scale AOD patterns are consistent with the surface measurements, remote SEVIRI & MODIS observations, and MERRA-2 reanalysis. The column-averaged aerosol size distribution in the model is generally in good agreement with the aircraft observations and the AERONET inversion product. Both WRF-Chem and AERONET underestimate the coarse mode especially during the strong dust events in comparison with the aircraft observations, although, model results are in a better agreement with observations.