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Intensity of the geomagnetic field in Europe for the last 3 ka: Influence of data quality on geomagnetic field modeling

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Pavón Carrasco, Francisco Javier and Gomez Paccard, Mirian and Gwenael, Gwenael and Osete López, María Luisa and Chauvin, Annick (2014) Intensity of the geomagnetic field in Europe for the last 3 ka: Influence of data quality on geomagnetic field modeling. Geochemistry, Geophysics, Geosystems, 15 (6). pp. 2515-2530. ISSN 1525-2027

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Official URL: http://dx.doi.org/ 10.1002/2014GC005311




Abstract

One of the main challenges of paleomagnetic research is to obtain high-resolution geomagnetic field intensity reconstructions. For the last millennia, these reconstructions are mostly based on archeomagnetic data. However, the quality of the intensity data available in the databases is very variable, and the high scatter observed in the records clearly suggests that some of them might not be reliable. In this work we investigate how the geomagnetic field intensity reconstructions and, hence, our present knowledge of the geomagnetic field in the past, are affected by the quality of the data selected for modeling the Earth’s magnetic ield. For this purpose we rank the European archeointensity data in four quality categories following widely accepted paleomagnetic criteria based on the methodology used during the laboratory treatment of the samples and on the number of specimens retained to calculate the mean intensities. Four geomagnetic field regional models have been implemented by applying the revised spherical cap harmonic analysis to these four groups of input data. Geomagnetic field models strongly depend on the used data set. The model built using all the available data (without any preselection) appears to be the less accurate, indicating some internal inconsistencies of the data set. In addition, some features of this model are clearly dominated by the less reliable archeointensity data, suggesting that such features might not reflect real variations of the past geomagnetic field. On the contrary, the regional model built on selected high-quality intensity data shows a very consistent intensity pattern at the European scale, confirming that the main intensity changes observed in Europe in the recent history of the geomagnetic field occurred at the continental scale.


Item Type:Article
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© 2014 American Geophysical Union.
We would like to express our thanks to the paleomagnetic community for the effort of providing the archeo/ paleomagnetic data and the construction and updating of useful databases. We are very grateful for the review and helpful comments of Ron Shaar and a second anonymous referee. This work has been carried out within the Spanish Research Project CGL2011–24790 financed by the Spanish Ministry of Economy and Competitiveness. Financial support to this research was also given by the post doc positions ME-Fulbright CT-2010-0663 and ‘‘Assegno di Ricerca’’ INGV - Roma2 (FJPC) and Marie Curie Intra European Fellowship IEF-2012 (MGP). E. Thebault is acknowledged for providing the software of the Mehler functions of the R-SCHA2D

Subjects:Sciences > Physics > Geophysics
ID Code:29277
Deposited On:20 Mar 2015 13:05
Last Modified:25 Mar 2015 09:10

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