Numerical simulation of a continental-scale Saharan dust event

Abstract

Using an integrated dust-storm modeling system, we simulate the severe Saharan dust episode between 1 and 10 March 2004. The simulations are compared with surface synoptic data and satellite images and are found to agree well with the observations. The synoptic systems that generated the dust storms and the evolution of the dust patterns are analyzed. It is revealed that a cyclogenesis over central Sahara, accompanied by an anticyclone over the Atlantic and a monsoon trough in the tropics, was responsible for the widespread continental-scale dust storms in North Africa. Dust first appeared in west Sahara, then in east Sahara and much of the dust emitted from east Sahara was transported to the monsoon trough, resulting in high concentrations of suspended dust over the Sahel (column dust load up to 10 g m -2). The main dust source regions were (1) Mauritania, (2) Chad and Niger, and (3) Libya, Egypt, and Sudan. The region between 10°N and 17°N was one of net dust deposition. We estimate that 715.8 megatons (Mt) of dust was emitted from North Africa during the episode, 608.2 Mt of which was deposited to the continent, and the net dust emission was 107.6 Mt. Of the 107.6 Mt, with respect to the model domain, 7.3 Mt was deposited to the ocean, 79.8 Mt was transported across the domain boundaries, and 20.5 Mt was suspended in the atmosphere. © 2010 by the American Geophysical Union.