Research Projects

Project at a Glance

Project Status: complete

Report Published September 1994:

Title: Generation, characterization and transport of Owens (dry) Lake dusts

Principal Investigator / Author(s): Cahill, Thomas

Contractor: University of California, Davis

Contract Number: a132-105


Research Program Area: Atmospheric Processes

Topic Areas: Monitoring, Transport


Abstract:

We investigated the sources of PM10 from the Owens Lake playa and its transport into both populated and wilderness areas. The levels of PM10 dust observed near the lake bed are among the highest ever seen in the United States. This study's result show that the dust is a consequence of the grinding of salt and silt components o fthe playa by wind-driven, saltating, coarse grains of sand, broken salt crust, and other debris. We ascertained that the lake bed forms saline crusts that, if not destroyed by sand or other causes, suppress or eliminate formation of PM10. The "fetch effect," in which the mass of wind-eroded soil increases with distance downwind, is shown to exist at Owens (Dry) Lake. Data from our intensive field study in March 1993 lead us to a conditional acceptance of three mechanisms causing the wind-erosion fetch effect: avalanching, soil resistance, and aerodynamic feedback. Particle sizes in the dust are generally much finer than soil based PM10. Due partly to the fine size and the topographically-confined transport paths, the dust is efficiently transported long distances north and south of the Owens Lake area, to sites including the Ancient Bristlecone Pine Forest and the Naval Air Weapons Station, China Lake. We also surveyed existing vegetation types of Owens (Dry) Lake and the conditions in which they survive, confirming the usefulness of native vegetation in dust suppression once sand motion has been controlled.


 

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