LOCAL METEOROLOGICAL, TRANSPORT, AND SOURCE AEROSOL CHARACTERISTICS OF LATE AUTUMN OWENS LAKE (DRY) DUST STORMS

The time evolution of aerosol generation in the saltation dominated fine particle production from Owens (dry) Lake, California, was measured by size and elemental composition for four dust events in November-December 1991. Time resolved aerosol size distributions were measured during all storm periods from genesis to cessation at the township of Keeler, less than 1 km from the border of one of the dust-producing regions. The size distributions of aerosols showed a much greater concentration of soil elements in very fine modes than is usual in typical soils, with a PM10 mass median diameter in the 2.5-5 mum size range. Four meteorological stations on and around the lake, time lapse photography of the northern lake bed, and nephelometers located 100 km to the south allowed for the continuous monitoring of local meteorology as well as transport patterns during storm periods. Local meteorological and transport patterns observed are discussed.