Energy dispersion in a barotropic atmosphere
| Autor: | A. J. Simmons, D. G. Andrews, Brian J. Hoskins |
|---|---|
| Rok vydání: | 1977 |
| Předmět: |
Physics
Atmospheric Science Atmospheric wave Equator Northern Hemisphere Mechanics Vorticity Atmospheric sciences Positive vorticity advection Barotropic fluid Astrophysics::Earth and Planetary Astrophysics Barotropic vorticity equation Dispersion (water waves) Physics::Atmospheric and Oceanic Physics |
| Zdroj: | Quarterly Journal of the Royal Meteorological Society. 103:553-567 |
| ISSN: | 1477-870X 0035-9009 |
| DOI: | 10.1002/qj.49710343802 |
| Popis: | The propagation of energy on the sphere as described by the linear barotropic vorticity equation is studied. For simple flows, the concept of group velocity is examined. Planetary-scale vorticity anomalies exhibit a surprising lack of dispersion in a hemispheric domain. On the sphere, there is more dispersion and a significant cross-equatorial propagation of energy. Planetary-scale vorticity sources tend to produce an orderly downstream train of waves which exhibit a strong tilt (NE-SW for sources in the northern hemisphere) and cross the equator. Zonally elongated sources produce an almost north-south train of waves. For realistic zonal flows with equatorial easterlies, large-scale transients cross the equator, but the long-term forced response in the opposite hemisphere is small. Comparison of the results with observations of atmospheric wave behaviour is made, and some possible implications are presented. |
| Databáze: | OpenAIRE |
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