Journal ArticleDOI
Saturated and Unsaturated Spectra of Gravity Waves and Scale-Dependent Diffusion
TLDR
In this article, the spectrum of gravity wave at each height is calculated directly from the wave equation and wave dissipation is approximately accounted for by a diffusion term, assuming that many wave dissipations can be approximately described by a scale-dependent diffusion process.Abstract:
For a highly idealized condition, the spectrum of saturated and unsaturated gravity waves at each height is calculated directly from the wave equation. A principal feature of this wave equation is the inclusion of wave dissipation, although in an approximate form. In the absence of wave absorption, reflection, radiation, wind shears, resonant wave–wave interactions and other sources and sinks, this dissipation at each height is determined solely by the “turbulent” or chaotic state caused by off-resonant wave–wave interactions and instability of the (broad) wave spectrum at that height. The dissipation is approximately accounted for by a diffusion term. The appropriate diffusivity is self-consistent with the continuum of spectral waves that cause the chaotic state and is argued to be scale dependent. An inverse calculation is also made of what the observed spectra imply for wave dissipation—again assuming that many wave dissipations can be approximately described by a scale-dependent diffusion pro...read more
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Journal ArticleDOI
Gravity wave dynamics and effects in the middle atmosphere
TL;DR: In this article, a review of gravity wave sources and characteristics, the evolution of the gravity wave spectrum with altitude and with variations of wind and stability, the character and implications of observed climatologies, and the wave interaction and instability processes that constrain wave amplitudes and spectral shape are discussed.
Journal ArticleDOI
Gravity wave activity in the lower atmosphere: Seasonal and latitudinal variations
Simon J. Allen,Robert A. Vincent +1 more
TL;DR: A climatology of gravity wave activity in the lower atmosphere based on high-resolution radiosonde measurements provided by the Australian Bureau of Meteorology is presented in this article, where the vertical wavenumber power spectra of normalized temperature fluctuations are calculated within both the troposphere and the lower stratosphere and compared with the predictions of current gravity wave saturation theories.
Journal ArticleDOI
An overview of the past, present and future of gravity-wave drag parametrization for numerical climate and weather prediction models
TL;DR: An overview of the parametrization of gravity wave drag in numerical weather prediction and climate simulation models is presented in this article, where the focus is primarily on understanding the current status of gravity-wave drag and the new parameters that will be needed for the next generation of atmospheric models.
Journal ArticleDOI
Self-similarity of strongly stratified inviscid flows
Paul Billant,Jean-Marc Chomaz +1 more
TL;DR: In this paper, the authors proposed a scaling law for strongly stratified flows in which the inviscid governing equations in the limit Fh→0, without any a priori assumption on the magnitude of Lv, are selfsimilar with respect to the variable zN/U, where z is the vertical coordinate.
Journal ArticleDOI
On the importance of gravity waves in the middle atmosphere and their parameterization in general circulation models
TL;DR: In this article, the authors discuss the problem of parameterizing unresolved gravity waves in general circulation models (GCMs) of the middle atmosphere and present a review of the basic dynamics of both the large-scale circulation and internal gravity waves.
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