Interaction between unvegetated desert surfaces and the atmospheric boundary layer: a preliminary assessment
The nature of interactions between surface winds and natural desert surfaces has important implications for aeolian sediment transport. We report here initial results from measurements of boundary layer wind profiles and surface roughness at 5 sites in Death Valley, U.S.A. and discuss their implications. The sites studied were a flat to gently undulating gravel and sand reg, three alluvial fan surfaces, including one with a well-developed desert pavement, and a silt and clay playa. Aerodynamic roughness estimates range from 0.00018 to 0.00537 m and increase in parallel with the visual estimates of topographic roughness at each site. Microtopography was measured with template and laser profiling devices. The standard deviation of surface elevations (RMS height) appears to provide a good index of surface roughness. It correlates well with field observations of topographic roughness and aerodynamic roughness estimates.
KeywordsAtmospheric Boundary Layer Wind Profile Bulk Richardson Number Laser Data Template Data
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