Campus Units

Geological and Atmospheric Sciences

Document Type

Article

Publication Version

Published Version

Publication Date

12-2011

Journal or Book Title

Acta Geophysica

Volume

59

Issue

6

First Page

1135

Last Page

1157

DOI

10.2478/s11600-011-0050-0

Abstract

EULAG is a computational model for simulating flows across a wide range of scales and physical scenarios. A standard option employs an anelastic approximation to capture nonhydrostatic effects and simultaneously filter sound waves from the solution. In this study, we examine a localized gravity wave packet generated by instabilities in Held-Suarez climates. Although still simplified versus the Earth’s atmosphere, a rich set of planetary wave instabilities and ensuing radiated gravity waves can arise. Wave packets are observed that have lifetimes ≤ 2 days, are negligibly impacted by Coriolis force, and do not show the rotational effects of differential jet advection typical of inertia-gravity waves. Linear modal analysis shows that wavelength, period, and phase speed fit the dispersion equation to within a mean difference of ∼ 4%, suggesting an excellent fit. However, the group velocities match poorly even though a propagation of uncertainty analysis indicates that they should be predicted as well as the phase velocities. Theoretical arguments suggest the discrepancy is due to nonlinearity — a strong southerly flow leads to a critical surface forming to the southwest of the wave packet that prevents the expected propagation.

Comments

This article is from Acta Geophysica. Volume 59, Issue 6, Pages 1135–1157, ISSN (Online) 1895-7455, ISSN (Print) 1895-6572, DOI: 10.2478/s11600-011-0050-0, October 2011

Rights

This work is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 3.0 License. (CC BY-NC-ND 3.0)

Copyright Owner

Institute for Geophysics, Polish Academy of Sciences

Language

en

File Format

application/pdf

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