Date of Award:
Master of Science (MS)
Plants, Soils, and Climate
Gene L. Woodridge
Constant volume superpressure pillow balloons were flown over a mountain valley downwind from a sharp ridge line. Balloon trajectories revealed and atmospheric soundings confirmed a persistent turbulently mixed adiabatic layer over the valley at approximately ridge top height except in the immediate lee of the ridge where strong vertical motions were observed. Temporary stationarity of the relative mesoscale turbulence was found to exist on a time scale exceeding 4 hours. Power spectrum analysis of component relative velocities showed greater variance in lower wave numbers and anisotropy in mesoscale turbulence. Eddy diffusivity coefficients for turbulence above the ridge height were Kx= 1×107 , Ky = 5×106 , Kz = 1×106 (cm2 sec-1). Below the ridge line Kz was nearly constant at 2×105 cm2/sec- 1. Kz was found to vary exponentially with R, a balloon-ridge ratio; Kz ∞ exp (3R).
Ellis, Ronan I., "Mesoscale Atmospheric Circulation and Diffusion Characteristics" (1973). All Graduate Theses and Dissertations. 3642.
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