Nonlinear MHD Rossby wave interactions and persistent geomagnetic field structures

 

Programa: 
meteorologia
Primeiro Autor: 
Breno Raphaldini
Ano de Publicação: 
2020
Nome da Revista/Jornal: 
Proceedings of the Royal Society A: Mathematical, Physical anda Engineering Sciences
Tipo de publicação: 
Artigo publicado em Revista
localidade: 
Publicação Internacional
TítuloNonlinear MHD Rossby wave interactions and persistent geomagnetic field structures
Tipo da publicaçãoJournal Article
Ano de Publicação2020
AutoresRaphaldini B, Raupp CFM
JournalProceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences
Volume476
Paginação1 a 20
Data de Publicação09/2020
ISSN1364-5021
Resumo

The geomagnetic field presents several stationary features that are thought to be linked to inhomogeneities at the core–mantle boundary. Particularly important stationary structures of the geomagnetic field are the flux lobes, which appear in pairs in mid- to high mid- to high latitudes. A recently discovered stratified layer at the top of the Earth’s core poses important constraints on the dynamics at this layer and on the interaction of the core dynamics and the base of the mantle. In this article, we introduce the linear and nonlinear theories of magnetic Rossby waves in a thin shell at the top of the Earth’s core. We study the nonlinear interaction of these waves in the presence of prescribed forcings at the base of the mantle of both a thermal and a topographic nature. We show that the combined effects of forcing and nonlinear interaction can lead the wave phases to be locked around a particular geographical longitude, generating a quasi- stationary flow pattern with a significant meridional component. The solutions of the system are shown to be analogous to atmospheric blocking phenomena. Therefore, we argue that persistent and long-lived structures of the geomagnetic field, such as the geomagnetic lobes, might be associated with a blocking at the top of the Earth’s core due to nonlinear stationary waves

URLhttps://royalsocietypublishing.org/doi/pdf/10.1098/rspa.2020.0174
DOI10.1098/rspa.2020.0174
Short TitleProc. R. Soc. A.