![]() The primary focus of T-REX is on mountain waves and wave-induced rotor circulations associated with the cross-barrier flow impinging on the sierra ridge. 2008), which took place over the Sierra Nevada and Owens Valley during March–April 2006. This study is partially motivated by observations obtained from the Terrain-induced Rotor Experiment (T-REX Grubišić et al. This allows the formation of a deep well-mixed layer in Owens Valley until the westerlies penetrate into the valley in the afternoon. Jiang and Doyle (2008) examined the westerly events that occurred in Owens Valley during March and April 2004 and found that the valley airflow is often decoupled from the prevailing westerlies above the mountaintop in the morning. The surface winds also exhibit strong diurnal variation in Owens Valley, generally with stronger winds during daytime and a peak frequency of high winds in the afternoon. The well-known westerly downslope windstorms are relatively rare. (2008) found that strong winds (defined as hourly mean wind speed above 7 m s −1) observed by stations on the valley floor are primarily bidirectional, either up-valley (i.e., south-southeasterly) or, less frequently, down-valley (i.e., north-northwesterly). ![]() In a recent study of the high wind climatology in Owens Valley, Zhong et al. 1995), reduce visibility, and harm vegetation ( Marchand 1970 Reheis 1997) as far as 100 mi away.įor given soil textures and wetness, the dust lofting is largely controlled by near-surface meteorological conditions, namely wind speed and stability (therefore, surface friction velocity). The fine salt-rich particles scoured off the dry lake bed by strong winds can cause a variety of health problems to human beings ( Abbey et al. It is believed that Owens (dry) Lake is the single largest source of aerosol particles with aerodynamic diameters smaller than 10 μm (PM-10) in the United States ( Reheis 1997). ![]() The windblown dust from the approximately 280-km 2 dry lakebed of Owens (dry) Lake, a toxic mixture of arsenic, cadmium, nickel, and sulfates, has been found across the western United States ( Gill and Gillette, 1991 Reid et al. The lake level dropped quickly after the Los Angeles Department of Water and Power (LADWP) started diverting the Owens River to feed the Los Angeles Aqueduct in 1913, and eventually became a dry lake by 1926. ![]() Historically, fed by streams such as the Owens River, Owens (dry) Lake was a perennial salt lake and an important stopover site for migrating birds in the western United States. While Owens Valley is nearly two-dimensional, the topography around Owens (dry) Lake is complex and highly three-dimensional with rich multiscale features ( Fig. Owens (dry) Lake is located in Owens Valley, which is a northwest–southeast-oriented quasi-two-dimensional valley between the Sierra Nevada ridge and the Inyo Mountains ( Fig. Assisted by strong turbulence and wave-induced vertical motion in the valley, the westerlies can transport a substantial fraction of the particulate mass across the Inyo Mountains into Death Valley National Park. The simulated strong westerlies reach the western part of the valley in the afternoon and more fine dust is scoured off Owens (dry) Lake than in the morning. In the morning, with the valley air decoupled from the prevailing westerlies (i.e., cross valley) above the mountaintop, fine particulates are blown off the dry lake bed by moderate up-valley winds and transported along the valley toward northwest. The strongest dust event documented during the 2-month-long period, with maximum hourly and daily average particulate concentrations of 70 μg m −3, respectively, is further examined using output from a high-resolution mesoscale aerosol model simulation. The hourly particulate concentration averaged over a 2-month period exhibits a strong diurnal variation with a primary maximum in the afternoon, coincident with a wind speed maximum. Air quality stations around Owens (dry) Lake observed dramatic temporal and spatial variations of surface winds and dust particulate concentration. Fine dust particles emitted from Owens (dry) Lake in California documented during the Terrain-Induced Rotor Experiment (T-REX) of 2006 have been examined using surface observations and a mesoscale aerosol model.
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