Abstract
Abstract. We used WRF-Chem, a regional meteorological model coupled with an aerosol-chemistry component, to simulate various aspects of the dust phenomena over the Arabian Peninsula and Red Sea during a typical winter-time dust event that occurred in January 2009. The model predicted that the total amount of emitted dust was 18.3 Tg for the entire dust outburst period and that the two maximum daily rates were ~2.4 Tg day−1 and ~1.5 Tg day−1, corresponding to two periods with the highest aerosol optical depth that were well captured by ground- and satellite-based observations. The model predicted that the dust plume was thick, extensive, and mixed in a deep boundary layer at an altitude of 3–4 km. Its spatial distribution was modeled to be consistent with typical spatial patterns of dust emissions. We utilized MODIS-Aqua and Solar Village AERONET measurements of the aerosol optical depth (AOD) to evaluate the radiative impact of aerosols. Our results clearly indicated that the presence of dust particles in the atmosphere caused a significant reduction in the amount of solar radiation reaching the surface during the dust event. We also found that dust aerosols have significant impact on the energy and nutrient balances of the Red Sea. Our results showed that the simulated cooling under the dust plume reached 100 W m−2, which could have profound effects on both the sea surface temperature and circulation. Further analysis of dust generation and its spatial and temporal variability is extremely important for future projections and for better understanding of the climate and ecological history of the Red Sea.
Highlights
M of the aerosol optical depth (AOD) to evaluate the radiative al., 2011, 2012) and many biogeochemical cycles by providimpact of aerosols
While the predictions for the coarse and accumulation modes are similar over the Red Sea, the coarse mode is mostly responsible for the dust loading over the regions with the highest dust concentrations, including the middle part of East North Africa, Rub Al Khali, and eastern coast of the Arabian Peninsula
The model simulated intense dust emissions over the basin of the Arabian Desert with the total amount of 18.3 Tg for the entire dust outburst period of 14 days and two daily maximums of ∼ 2.4 Tg and ∼ 1.5 Tg, which corresponded to two periods with the highest AOD captured by AERONET and MODIS instruments
Summary
The WRF model is a state-of-the-art numerical weather prediction system designed to simulate atmospheric processes for both research and operational applications (Skamarock et al, 2008). The model has been used to simulate atmospheric processes over a wide range of spatial and temporal scales. The model uses a generalized vertical terrain-following coordinate system and takes into account a variety of physical processes such as boundary layer meteorology, deep and shallow convection, radiation, and land surface processes. The chemistry component is fully coupled with the meteorological model and both components use the same transport scheme, integration grid, physics parameterizations, and time steps. The chemistry component takes into account a variety of coupled physical and chemical processes such as transport, deposition, chemical transformations, aerosol interactions, photolysis, radiation, and emissions
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