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Non-Dipole and Regional Effects on the Geomagnetic Dipole Moment Estimation
Language
English
Obiettivo Specifico
1A. Geomagnetismo e Paleomagnetismo
Status
Published
JCR Journal
JCR Journal
Peer review journal
Yes
Title of the book
Issue/vol(year)
/172 (2015)
ISSN
0033-4553
Electronic ISSN
1420-9136
Publisher
Springer Verlag
Pages (printed)
91-107
Issued date
2015
Subjects
Abstract
The study of the temporal evolution of the dipole
moment variations is a forefront research topic in Earth sciences. It
constrains geodynamo simulations and is used to correct cosmogenic
isotope production, which is evidence of past solar activity,
and it is used to study possible correlations between the geomagnetic
field and the climate. In this work, we have analysed the main
error sources in the geomagnetic dipole moment computation from
palaeomagnetic data: the influence of the non-dipole terms in the
average approach, the inhomogeneous distribution of the current
palaeomagnetic database, and the averaging procedure used to
obtain the evolution of the dipole moment. To evaluate and
quantify these effects, we have used synthetic data from a global
model based on instrumental and satellite data, the International
Geomagnetic Reference Field: 11th generation. Results indicate
that the non-dipole terms contribute on a global scale of <6% in
the averaged dipole moment, whereas the regional non-dipole
contribution can show deviations of up to 35 % in some regions
such as Oceania, and different temporal trends with respect to the
global dipole moment evolution in other ones, such as Europe and
Asia. A regional weighting scheme seems the best option to mitigate
these effects in the dipole moment average approach. But
when directional and intensity palaeomagnetic information is
available on a global scale, and in spite of the inhomogeneity of the
database, global modelling presents more reliable values of the
geomagnetic dipole moment.
moment variations is a forefront research topic in Earth sciences. It
constrains geodynamo simulations and is used to correct cosmogenic
isotope production, which is evidence of past solar activity,
and it is used to study possible correlations between the geomagnetic
field and the climate. In this work, we have analysed the main
error sources in the geomagnetic dipole moment computation from
palaeomagnetic data: the influence of the non-dipole terms in the
average approach, the inhomogeneous distribution of the current
palaeomagnetic database, and the averaging procedure used to
obtain the evolution of the dipole moment. To evaluate and
quantify these effects, we have used synthetic data from a global
model based on instrumental and satellite data, the International
Geomagnetic Reference Field: 11th generation. Results indicate
that the non-dipole terms contribute on a global scale of <6% in
the averaged dipole moment, whereas the regional non-dipole
contribution can show deviations of up to 35 % in some regions
such as Oceania, and different temporal trends with respect to the
global dipole moment evolution in other ones, such as Europe and
Asia. A regional weighting scheme seems the best option to mitigate
these effects in the dipole moment average approach. But
when directional and intensity palaeomagnetic information is
available on a global scale, and in spite of the inhomogeneity of the
database, global modelling presents more reliable values of the
geomagnetic dipole moment.
Type
article
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15. Campuzano et al., 2014.pdf
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2.12 MB
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