15.11
Statistical Properties and Characteristics of Boundaries in the ABL
Haldun Karan, University of Alabama, Huntsville, AL; and K. R. Knupp
The characteristics of various types of boundaries within the atmospheric boundary layer, derived from the UAH Mobile Integrated Profiling System (MIPS composed of a 915 MHz profiler, a 2 kHz Doppler sodar, near-infrared (0.906 m) lidar ceilometer, a 12-channel microwave radiometer, surface instrumentation) are summarized. The diverse data set includes observations of boundaries from northern Alabama (all seasons), southeast Texas (summer), and the Florida Keys (summer). In this study we have classified boundaries according to type (gust fronts, land/sea breeze fronts, gravity/solitary waves, and warm/cold fronts). For each boundary, various kinematic quantities are analyzed, including boundary width, depth, vertical motion characteristics, turbulence, cloud properties, and changes in wind and thermodynamic properties across the boundary. Details of the vertical structures of the boundaries are analyzed from time series of 915 MHz profiler SNR, mean vertical motion, spectral width (turbulence), vertical variation of the horizontal wind vector, RASS virtual temperature profiles, sodar return power, and ceilometer backscatter. A variety of gust fronts have been observed, ranging from shallow gust fronts modified by surface fluxes over water in the Florida Keys region, to deep, vigorous gust fronts observed within the deep, dry ABL of southeast Texas during August-September 2000 time frame. In addition, a wide variety of sea breeze fronts observed over SE Texas and the Florida Keys, are associated with more subtle changes in kinematic and thermodynamic properties.
Session 15, Boundary Layers over Heterogeneous Surfaces
Friday, 19 July 2002, 8:30 AM-12:15 PM
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