Observational evidence of a saturated gravity wave spectrum in the troposphere and lower stratosphere

Abstract

The spectrum is dominated by low-frequency gravity waves with an upward sense of propagation in the lower stratosphere and both upward and downward propagation in the troposphere. Results indicate excellent agreement of the observed and predicted velocity and temperature spectra in both amplitude and slope. Vertical wavenumber spectra in area-preserving form reveal a dominant vertical wavelength of ~2.5km, systematic variations in energy density and the dominant vertical scale with time, and consistency between the temporal variations of velocity and temperature variance. Velocity and temperature fluctuations are due primarily to internal gravity waves and to the saturated spectrum theory and its imposed constraints on wave amplitudes and spectral shape. -from Authors