| Full text | |
| Author(s): |
Raphaldini, B.
[1, 2]
;
Teruya, A. S. W.
[1]
;
Raupp, C. F. M.
[1]
;
Silva-Dias, P. L.
[1]
;
Takahashi, D. Y.
[3]
Total Authors: 5
|
| Affiliation: | [1] Univ Sao Paulo, Inst Astron Geophys & Atmospher Sci, Rua Matao 1226, Cidade Univ, Sao Paulo, SP - Brazil
[2] Univ Durham, Dept Math Sci, Stockton Rd, Durham DH1 3LE - England
[3] Brain Inst, Av Nascimento Castro 2155, BR-59056450 Natal, RN - Brazil
Total Affiliations: 3
|
| Document type: | Journal article |
| Source: | European Physical Journal-Special Topics; v. 230, n. 14-15, p. 2999-3007, OCT 2021. |
| Web of Science Citations: | 1 |
| Abstract | |
The geomagnetic field is generated by a dynamo process in the Earth's core and is characterized by a predominant dipole component that has been steadily decreasing in the last few centuries. The physical drivers behind the fluctuations of the geomagnetic dipole field remain poorly understood. One of the possible explanations rely on the interaction between the dipole mode and other multipole terms of the geomagnetic field. To test this hypothesis, we used two millennial scale models based on spherical harmonic fitting of paleomagnetic data, which allowed to reconstruct the geomagnetic field of the past. By performing causality and information statistical analysis, we found significant interactions between the dipole and smaller scale harmonics (quadrupole and octupole) of the geomagnetic field. In particular, both data sets agree that the spherical harmonic Y-2(2) acts as a source term, whereas the axial dipole term Y-1(0) consists of the term with least information loss. The results suggest a possible control of core-mantle boundary inhomogeneities on the interaction between the components of the geomagnetic field. Our results also show a net information flux from larger to smaller scales, which is compatible with a direct turbulent cascade view of the geodynamo. (AU) | |
| FAPESP's process: | 17/23417-5 - Paleoclimatic variability of South Atlantic Convergence Zone and processes in the Atlantic and Pacific Oceans: Last Glacial, Middle Holocene and Last Millennium |
| Grantee: | Breno Raphaldini Ferreira da Silva |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |
| FAPESP's process: | 15/50122-0 - Dynamic phenomena in complex networks: basics and applications |
| Grantee: | Elbert Einstein Nehrer Macau |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 15/50686-1 - Paleo-constraints on monsoon evolution and dynamics |
| Grantee: | Pedro Leite da Silva Dias |
| Support Opportunities: | Research Projects - Thematic Grants |