Dust mobilization due to density currents in the Atlas region: Observations from the Saharan Mineral Dust Experiment 2006 field campaign

摘要: [1] Evaporation of precipitation is a ubiquitous feature dry and hot desert environments. The resulting cooling often generates density currents with strong turbulent winds along their leading edges, which can mobilize large amounts dust. Mountains support this process by triggering convection, downslope acceleration the cool air, fostering accumulation fine-grained sediments foothills through action water. For Sahara, world's largest dust source, mechanism has been little studied because lack sufficiently high resolution observational data. present study demonstrates frequent occurrence Sahara side Atlas Mountain chain in southern Morocco using unique data set collected during Saharan Mineral Dust Experiment (SAMUM) field campaign May/June 2006. are related to convection over mountains afternoon hours have lifetimes on order 10 h. passage sharp edge that sometimes reaches several hundred kilometers length usually associated marked increase dew point wind speed, change direction, decrease temperature visibility due suspended It conceivable relevant for other mountainous regions northern Africa warm season. This would imply simulations cycle numerical models need reliable representation moist convective processes generate realistic emissions from Sahara.