The impact of dust storms on the Arabian Peninsula and the Red Sea

Located in the dust belt, the Arabian Peninsula is a major source of atmospheric dust. Frequent dust outbreaks and some 15 to 20 dust storms per year have profound effects on all aspects of human activity and natural processes in this region. To quantify the effect of severe dust events on radiation fluxes and regional climate characteristics, we simulated the storm that occurred from 18 to 20 March 2012 using a regional weather research forecast model fully coupled with the chemistry/aerosol module (WRF-Chem). This storm swept over a remarkably large area affecting the entire Middle East, northeastern Africa, Afghanistan, and Pakistan. It was caused by a southward propagating cold front, and the associated winds activated the dust production in river valleys of the lower Tigris and Euphrates in Iraq; the coastal areas in Kuwait, Iran, and the United Arab Emirates; the Rub al Khali, An Nafud, and Ad Dahna deserts; and along the Red Sea coast on the west side of the Arabian Peninsula. Our simulation results compare well with available ground-based and satellite observations. We estimate the total amount of dust generated by the storm to have reached 94 Mt. Approximately 78% of this dust was deposited within the calculation domain. The Arabian Sea and Persian Gulf received 5.3 Mt and the Red Sea 1.2 Mt of dust. Dust particles bring nutrients to marine ecosystems, which is especially important for the oligotrophic Northern Red Sea. However, their contribution to the nutrient balance in the Red Sea remains largely unknown. By scaling the effect of one storm to the number of dust storms observed annually over the Red Sea, we estimate the annual dust deposition to the Red Sea, associated with major dust storms, to be 6 Mt.