Near surface atmospheric turbulence and surface temperature correlations

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Thursday, 6 February 2014: 11:45 AM
Room C206 (The Georgia World Congress Center )
Tim Price, University of Utah, Salt Lake City, UT; and V. Kulandaivelu, D. Jensen, E. Pardyjak, S. Hoch, and H. J. S. Fernando

Surface temperature is an important aspect of the unstable convective boundary layer and is a critical parameter for boundary layer modeling techniques. Previous work has shown that the surface temperature spatial and temporal statistics are strongly linked to atmospheric turbulence statistics and overall atmospheric stability. High frequency and high-resolution surface temperature and turbulence data were obtained during the Spring 2013 MATERHORN field campaign over the dry lakebed playa at the SLTEST facility in Utah's West Desert on the US Army Dugway Proving Grounds. This site features a large undisturbed fetch with very low surface roughness. Near surface turbulence was measured with a vertical array of hot and cold wire probes and a vertical array of fine-wire thermocouples allowing for computation of most terms of the local momentum and temperature transport equations. Surface temperature was measured using a high frequency thermal camera co-located with the turbulence measurements. Soil thermal properties were sampled intensively resulting in a well-characterized sub-surface thermal model. The resulting surface temperature fluctuations are shown to exhibit multi-scale temporal and spatially coherent structures correlating with surface layer turbulence and advection velocity. Using conditional averaging and quadrant-hole analysis, the role of sweep and ejection events on sensible heat flux is also explored.