| Full text | |
| Author(s): |
Terra-Nova, Filipe
[1, 2]
;
Amit, Hagay
[2]
;
Hartmann, Gelvam A.
[1, 3]
;
Trindade, Ricardo I. F.
[1]
Total Authors: 4
|
| Affiliation: | [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
Total Affiliations: 3
|
| Document type: | Journal article |
| Source: | JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH; v. 120, n. 2, p. 691-704, FEB 2015. |
| Web of Science Citations: | 13 |
| Abstract | |
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) | |
| FAPESP's process: | 10/10754-4 - Evolution of the Earth Magnetic Field in South America for the past 500 years |
| Grantee: | Gelvam André Hartmann |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 13/14629-8 - Spatio-temporal variations of archeomagnetic flux patches |
| Grantee: | Filipe Terra Nova dos Santos |
| Support Opportunities: | Scholarships abroad - Research Internship - Scientific Initiation |