Persistence of the South Atlantic Anomaly in geomagnetic observations, field models and numerical dynamos

• Grant number: 18/07410-3
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• Effective date (Start): August 01, 2018
• Effective date (End): July 31, 2021
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geophysics
• Principal Investigator: Ricardo Ivan Ferreira da Trindade
• Grantee: Filipe Terra Nova dos Santos
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil

Abstract

The geomagnetic field is generated by convection motions of an electrically conducting fluid at Earth's outer core. The field is measured directly at Earth's surface by observatories and at space by dedicated satellites. For periods preceding direct magnetic measurements, analysis of archeological material provides vital information about the field. Though complete self-consistent 3D solutions to all relevant fields inside the core, i.e. velocity, magnetic field and temperature (or co-density) can be only obtained with numerical dynamo simulations. Here in this project we explore geomagnetic observation, field models and numerical dynamo simulations to study the persistence of the South Atlantic Anomaly, which is the region of weakest intensity field at Earth's surface presently located on inland Brazil. The anomaly persistent in Brazil can have several societal impacts. This region is less shielded by the Earth's magnetic field and thus bombarded by energetic particle that degrade electronics , optics, solar panels , and other critical systems by braking chemical bonds and disrupting crystalline structures. Our key questions are: the dynamical origin on the core of low field intensity registered in archeomagnetic field series, how old are the South Atlantic Anomaly, is it the South Atlantic Anomaly mantle controlled, how does the heterogeneous CMB heat flux prescribe preferential convection and weak surface field and how does the amplitude of tomographic heterogeneous CMB heat flux determine dynamo regimes (dipolar or reversing) and properties.

Scientific publications

(7)

(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)

TERRA-NOVA, FILIPE; AMIT, HAGAY. Magnetic boundary layers in numerical dynamos with heterogeneous outer boundary heat flux. PHYSICS OF THE EARTH AND PLANETARY INTERIORS, v. 309, DEC 2020. (18/07410-3)

TERRA-NOVA, FILIPE; AMIT, HAGAY; CHOBLET, GAEL. Preferred locations of weak surface field in numerical dynamos with heterogeneous core-mantle boundary heat flux: consequences for the South Atlantic Anomaly. Geophysical Journal International, v. 217, n. 2, p. 1179-1199, MAY 2019. (18/07410-3)

PINHEIRO, K. J.; AMIT, H.; TERRA-NOVA, F.. Geomagnetic jerk features produced using synthetic core flow models. PHYSICS OF THE EARTH AND PLANETARY INTERIORS, v. 291, p. 35-53, JUN 2019. (18/07410-3)

AMIT, HAGAY; TERRA-NOVA, FILIPE; LEZIN, MAXIME; TRINDADE, RICARDO I.. Non-monotonic growth and motion of the South Atlantic Anomaly. EARTH PLANETS AND SPACE, v. 73, n. 1, DEC 8 2021. (18/07410-3)

JAQUETO, PLINIO; TRINDADE, RICARDO I. F.; TERRA-NOVA, FILIPE; FEINBERG, JOSHUA M.; NOVELLO, VALDIR F.; STRIKIS, NICOLAS M.; SCHROEDL, PETER; AZEVEDO, VITOR; STRAUSS, BECK E.; CRUZ, FRANCISCO W.; et al. Stalagmite paleomagnetic record of a quiet mid-to-late Holocene field activity in central South America. NATURE COMMUNICATIONS, v. 13, n. 1, p. 10-pg., 2022-03-15. (16/15807-5, 18/07410-3, 19/06709-8, 18/15774-5, 16/24870-2, 17/50085-3)

TRINDADE, RICARDO I. F.; JAQUETO, PLINIO; TERRA-NOVA, FILIPE; BRANDT, DANIELE; HARTMANN, GELVAM A.; FEINBERG, JOSHUA M.; STRAUSS, BECKY E.; NOVELLO, VALDIR F.; CRUZ, FRANCISCO W.; KARMANN, IVO; et al. Speleothem record of geomagnetic South Atlantic Anomaly recurrence. PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, v. 115, n. 52, p. 13198-13203, DEC 26 2018. (17/50085-3, 18/07410-3, 16/15807-5, 16/24870-2, 16/00299-4)

TERRA-NOVA, FILIPE; AMIT, HAGAY; CHOBLET, GAEL; TOBIE, GABRIEL; BOUFFARD, MATHIEU; CADEK, ONDREJ. The influence of heterogeneous seafloor heat flux on the cooling patterns of Ganymede's and Titan's subsurface oceans. ICARUS, v. 389, p. 15-pg., 2023-01-01. (18/07410-3)