Recurrent ancient geomagnetic field anomalies shed light on future evolution of the South Atlantic Anomaly
Nilsson, Andreas LU ; Suttie, Neil LU
; Stoner, Joseph S.
and Muscheler, Raimund
LU
(2022)
In Proceedings of the National Academy of Sciences of the United States of America
119(24).
- Abstract
The strength of the geomagnetic field has decreased rapidly over the past two centuries, coinciding with an increasing field asymmetry due to the growth of the South Atlantic Anomaly. The underlying processes causing the decrease are debated, which has led to speculation that the field is about to reverse. Here, we present a geomagnetic field model based on indirect observations over the past 9,000 y and identify potential ancient analogs. The model is constructed using a probabilistic approach that addresses problems with age uncertainties and smoothing of sedimentary data that have hampered previous attempts. We find evidence for recurrent hemispherical field asymmetries, related to quasiperiodic millennial-scale variations in the... (More)
The strength of the geomagnetic field has decreased rapidly over the past two centuries, coinciding with an increasing field asymmetry due to the growth of the South Atlantic Anomaly. The underlying processes causing the decrease are debated, which has led to speculation that the field is about to reverse. Here, we present a geomagnetic field model based on indirect observations over the past 9,000 y and identify potential ancient analogs. The model is constructed using a probabilistic approach that addresses problems with age uncertainties and smoothing of sedimentary data that have hampered previous attempts. We find evidence for recurrent hemispherical field asymmetries, related to quasiperiodic millennial-scale variations in the dipole moment. Our reconstruction indicates that minima in the dipole moment tend to coincide with geomagnetic field anomalies, similar to the South Atlantic Anomaly. We propose that the period around 600 BCE, characterized by a strongly asymmetric field, could provide an analog to the present-day field. The analogy implies that the South Atlantic Anomaly will likely disappear in next few hundred years, accompanied by a return to a more symmetric field configuration and possibly, a strengthening of the axial dipole field.
(Less)
- author
- Nilsson, Andreas
LU
; Suttie, Neil
LU
; Stoner, Joseph S.
and Muscheler, Raimund
LU
- organization
- publishing date
- 2022-06-14
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- geomagnetism, paleomagnetism, South Atlantic Anomaly
- in
- Proceedings of the National Academy of Sciences of the United States of America
- volume
- 119
- issue
- 24
- article number
- e2200749119
- publisher
- National Academy of Sciences
- external identifiers
-
- scopus:85131341065
- pmid:35666861
- ISSN
- 0027-8424
- DOI
- 10.1073/pnas.2200749119
- language
- English
- LU publication?
- yes
- id
- c705c5c1-b4a5-4f59-83da-0acaf3564574
- date added to LUP
- 2022-09-06 10:56:00
- date last changed
- 2024-06-13 18:54:08
@article{c705c5c1-b4a5-4f59-83da-0acaf3564574,
abstract = {{<p>The strength of the geomagnetic field has decreased rapidly over the past two centuries, coinciding with an increasing field asymmetry due to the growth of the South Atlantic Anomaly. The underlying processes causing the decrease are debated, which has led to speculation that the field is about to reverse. Here, we present a geomagnetic field model based on indirect observations over the past 9,000 y and identify potential ancient analogs. The model is constructed using a probabilistic approach that addresses problems with age uncertainties and smoothing of sedimentary data that have hampered previous attempts. We find evidence for recurrent hemispherical field asymmetries, related to quasiperiodic millennial-scale variations in the dipole moment. Our reconstruction indicates that minima in the dipole moment tend to coincide with geomagnetic field anomalies, similar to the South Atlantic Anomaly. We propose that the period around 600 BCE, characterized by a strongly asymmetric field, could provide an analog to the present-day field. The analogy implies that the South Atlantic Anomaly will likely disappear in next few hundred years, accompanied by a return to a more symmetric field configuration and possibly, a strengthening of the axial dipole field.</p>}},
author = {{Nilsson, Andreas and Suttie, Neil and Stoner, Joseph S. and Muscheler, Raimund}},
issn = {{0027-8424}},
keywords = {{geomagnetism; paleomagnetism; South Atlantic Anomaly}},
language = {{eng}},
month = {{06}},
number = {{24}},
publisher = {{National Academy of Sciences}},
series = {{Proceedings of the National Academy of Sciences of the United States of America}},
title = {{Recurrent ancient geomagnetic field anomalies shed light on future evolution of the South Atlantic Anomaly}},
url = {{http://dx.doi.org/10.1073/pnas.2200749119}},
doi = {{10.1073/pnas.2200749119}},
volume = {{119}},
year = {{2022}},
}