| Description |
This study provides a holistic view of dust storms and transport in the eastern Great Basin, and is the first to analyze the meteorological, source, and chemical characteristics of dust production in this region. First, the climatology of dust storm events affecting Salt Lake City, Utah (SLC) was assessed, and the controls on atmospheric dust generation and transport documented. Records indicate seasonal and diurnal patterns, with dust storms typically occurring in spring months during the afternoon. Since 1930, SLC had 379 dust event days (DEDs), averaging 4.7 per year, with elevated PM10 exceeding National Ambient Air Quality Standards (NAAQS) on 16 days since 1993, or 0.9 per year. Strengthening cyclonic systems are the primary producer of these dust storms. Next anthropogenically disturbed areas and barren playa surfaces were identified as the primary dust source types contributing to dust storms in the region. Moderate Resolution Imaging Spectroradiometer (MODIS) satellite imagery during DEDs was analyzed to identify dust plumes, and assess the characteristics of dust source areas, which produce dust during the spring and fall and during drought. Most plumes originate from playas, classified as Barren land cover, with a silty clay soils; they often have anthropogenic disturbances, including military operations and water withdrawal. Disturbance is necessary to produce dust from vegetated landscapes in the region, evidenced by the new dust source active from 2008-2010 in the 2007 Milford Flat Fire scar, which underwent postfire land treatments. Finally, the elemental composition of dust in the region was characterized. Dust and surface soil samples were collected, resuspended, and analyzed with Sychrotron XRay Fluorescence (SXRF). Dust and soil from the eastern Great Basin are distinctly different, and identifiable. Within the dust and soil groups, however, large differences are not seen and individual samples cannot be identified by their elemental composition. Dust and soil from the eastern Great Basin tends to not be enriched in most major soil elements, excepting a large enrichment of Na in dust samples. Trace elements, however, show very large enrichment values for both dust and soil. The enrichment of dust samples has notable importance for ecosystem functioning and human health. |
