סמינר בחוג למדעי כדור הארץ: Effect of Terrain Relief on the Transport of Dust Aerosol

Abstract:

The terrain relief may also affect the aerosol propagation. First, some places may play role of certain traps where the aerosol brought from distant regions can be accumulated. This, for example, can happen in valleys as the dust-carrying air flow reaches them. Second, the relief can channelize the dust-loaded air mass flow resulting in appearance of predominant transport path. In this paper, we will consider both the examples of aerosol traps and aerosol transport channels associated with relief. Accumulation of the desert dust in Po valley in front of Alps as the dust-carrying air flow from North Africa reaches them and slows down was observed in (Israelevich et al., 2012) using MODIS data. Analysis of Aeronet data performed here confirms this conclusion. Using MISR Aerosol Optical thickness we show that during summer months southern part of the Red Sea becomes a trap for dust aerosol. The Red Sea is filled with the dust both from the African and Arabian sides, but the main entrance for the dust is the valley between Ethiopian Highlands and Red Sea Hills at 180N 37.50E. The  Atlas, Ahaggar and Tibesti mountain chains are located on the way of northward flow of dust containing air masses from the major sources of Saharan desert aerosols. These obstructions result in enhanced transport channels – one through the passage between Atlas and Ahaggar mountains, and two others between Ahaggar and Tibesti, and Marrah Mountains.

מארגנת הסמינר: ד"ר רוית חלד