An alternative view on the role of the beta-effect in the Rossby wave propagation mechanism
2014 (English)In: Tellus. Series A, Dynamic meteorology and oceanography, ISSN 0280-6495, E-ISSN 1600-0870, Vol. 66, 22672- p.Article in journal (Refereed) Published
The role of the beta-effect in the Rossby wave propagation mechanism is examined in the linearised shallow water equations directly in momentum-height variables, without recourse to potential vorticity (PV). Rigorous asymptotic expansion of the equations, with respect to the small non-dimensionalised beta parameter, reveals in detail how the Coriolis force acting on the small ageostrophic terms translates the geostrophic leading-order solution to propagate westward in concert. This information cannot be obtained directly from the conventional PV perspective on the propagation mechanism. Furthermore, a comparison between the beta-effect in planetary Rossby waves and the sloping-bottom effect in promoting topographic Rossby waves shows that the ageostrophic terms play different roles in the two cases. This is despite the fact that from the PV viewpoint whether the advection of mean PV gradient is set up by changes in planetary vorticity or by mean depth is inconsequential.
Place, publisher, year, edition, pages
2014. Vol. 66, 22672- p.
Rossby wave propagation, momentum-pressure perspective, role of ageostrophic flow, beta plane, sloping bottom
Meteorology and Atmospheric Sciences
IdentifiersURN: urn:nbn:se:su:diva-111706DOI: 10.3402/tellusa.v66.22672ISI: 000345902000001OAI: oai:DiVA.org:su-111706DiVA: diva2:776521