Kinetic equations and stationary energy spectra of weakly nonlinear internal gravity waves |
| |
Authors: | P Caillol V Zeitlin |
| |
Institution: | Laboratoire de Météorologie Dynamique, BP 99, Université P. et M. Curie, 4, pl. Jussieu, 75252 Paris Cedex 05, France |
| |
Abstract: | An ensemble of random-phase internal gravity waves is considered in the dynamical framework of the Euler–Boussinesq equations. For flows with zero mean potential vorticity, a kinetic equation for the mean spectral energy density of the waves is obtained under hypothesis of Gaussian statistics with zero correlation length. Stationary scaling solutions of this equation are found for almost vertically propagating waves. The resulting spectra are anisotropic in vertical and horizontal wave numbers. For flows with small but non-zero mean potential vorticity, under the same statistical hypothesis applied to the wave part of the flow, it is shown that the vortex part and the wave part decouple. The vortex part obeys a limiting slow dynamics equation exhibiting vertical collapse and layering which may contaminate the wave-part spectra. Relation of these results to the in situ atmospheric measurements and previous work on oceanic gravity waves is discussed. |
| |
Keywords: | Kinetic equations Stationary energy spectra Nonlinear internal gravity waves |
本文献已被 ScienceDirect 等数据库收录! |
|