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Ann. Geophys., 26, 2037-2042, 2008
www.ann-geophys.net/26/2037/2008/
© European Geosciences Union 2008
Three-dimensional spectrum of temperature fluctuations in stably stratified atmosphere
A. S. Gurvich and I. P. Chunchuzov
Oboukhov Institute of Atmospheric Physics, Moscow 119017, Russia
Abstract. A phenomenological model is proposed for a 3-D spectrum of temperature
inhomogeneities generated by internal waves in the atmosphere. This model is
a development of the theory based on the assumption that a field of
Lagrangian displacements of fluid particles, induced by an ensemble of
internal waves with randomly independent amplitudes and phases, is
statistically stationary, homogeneous, axially symmetric in horizontal plane
and Gaussian. For consistency of this model with measured spectra of
temperature fluctuations in the stratosphere and mesosphere the additional
assumption was introduced in to the model about the anisotropy of
inhomogeneities to be dependent on their vertical sizes. The analytic
expressions for both the 3-D and 1-D spectra are obtained. A model vertical
wave number spectrum follows a −3 power law, whereas a horizontal spectrum
contains two regions with a −3 slope, and the intermediate region with the
slope between −1 and −3 depending on the rate of anisotropy decrease as a
function of increasing sizes of the inhomogeneities. In the range of a few
decades the model showed a good agreement with the results of measurements
of the spectra in the troposphere, stratosphere and mesosphere.
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