Longitudinal and Lateral Spectra of Turbulence in the Atmospheric Boundary Layer at the Kennedy Space Center

Abstract

An engineering spectral model of turbulence is developed with horizontal wind observations obtained at the NASA 150-m meteorological tower at Cape Kennedy, Fla. Spectra, measured at six levels, are collapsed at each level with [nS(n)/u*02,f]-coordinates, where S(n) is the longitudinal or lateral spectral energy density at frequency n(Hz), u*0 the surface friction velocity, and f = nz/?, ? being the mean wind speed at height z. A vertical collapse of the dimensionless spectra is produced by assuming they are shape-invariant in the vertical. An analysis of the longitudinal spectrum in the inertial subrange, at the 18-m level, implies that the local mechanical and buoyant production rates of turbulent kinetic energy are balanced by the local dissipation and energy flux divergence, respectively.