| Texto completo | |
| Autor(es): |
Terra-Nova, Filipe
[1, 2]
;
Amit, Hagay
[2]
;
Hartmann, Gelvam A.
[1, 3]
;
Trindade, Ricardo I. F.
[1]
Número total de Autores: 4
|
| Afiliação do(s) autor(es): | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, Dept Geofis, Sao Paulo - Brazil
[2] Nantes Atlantiques Univ, Univ Nantes, CNRS, Lab Planetol & Geodynam, UMR CNRS 6112, Nantes - France
[3] Observ Nacl, Rio De Janeiro - Brazil
Número total de Afiliações: 3
|
| Tipo de documento: | Artigo Científico |
| Fonte: | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH; v. 120, n. 2, p. 691-704, FEB 2015. |
| Citações Web of Science: | 13 |
| Resumo | |
Archeomagnetic field models may provide important insights to the geodynamo. Here we investigate the existence and mobility of reversed flux patches (RFPs) in an archeomagnetic field model. We introduce topological algorithms to define, identify, and track RFPs. In addition, we explore the relations between RFPs and dipole changes and apply robustness tests to the RFPs. In contrast to previous definitions, patches that reside on the geographic equator are adequately identified based on our RFPs definition. Most RFPs exhibit a westward drift and migrate toward higher latitudes. Undulations of the magnetic equator and RFPs oppose the axial dipole moment (ADM). Filtered models show a tracking behavior similar to the nonfiltered model, and surprisingly new RFPs occasionally emerge. The advection and diffusion of RFPs have worked in unison to yield the decrease of the ADM at recent times. The absence of RFPs in the period 550-1440 A.D. is related to a low in intermediate degrees of the geomagnetic power spectrum. We thus hypothesize that the RFPs are strongly dependent on intermediate spherical harmonic degrees4 and above. (AU) | |
| Processo FAPESP: | 10/10754-4 - Evolução do campo magnético terrestre na América do Sul para os últimos 500 anos |
| Beneficiário: | Gelvam André Hartmann |
| Modalidade de apoio: | Bolsas no Brasil - Pós-Doutorado |
| Processo FAPESP: | 13/14629-8 - Variações temporais e espaciais dos lóbulos de fluxo do campo arqueomagnético |
| Beneficiário: | Filipe Terra Nova dos Santos |
| Modalidade de apoio: | Bolsas no Exterior - Estágio de Pesquisa - Iniciação Científica |