TY  - JOUR
A1  - Lesur, Vincent
A1  - Wardinski, Ingo
A1  - Bärenzung, Julien
A1  - Holschneider, Matthias
T1  - On the frequency spectra of the core magnetic field Gauss coefficients
JF  - Physics of the earth and planetary interiors
N2  - From monthly mean observatory data spanning 1957-2014, geomagnetic field secular variation values were calculated by annual differences. Estimates of the spherical harmonic Gauss coefficients of the core field secular variation were then derived by applying a correlation based modelling. Finally, a Fourier transform was applied to the time series of the Gauss coefficients. This process led to reliable temporal spectra of the Gauss coefficients up to spherical harmonic degree 5 or 6, and down to periods as short as 1 or 2 years depending on the coefficient. We observed that a k(-2) slope, where k is the frequency, is an acceptable approximation for these spectra, with possibly an exception for the dipole field. The monthly estimates of the core field secular variation at the observatory sites also show that large and rapid variations of the latter happen. This is an indication that geomagnetic jerks are frequent phenomena and that significant secular variation signals at short time scales - i.e. less than 2 years, could still be extracted from data to reveal an unexplored part of the core dynamics.
KW  - Geomagnetism
KW  - Core field
KW  - Secular variation rate of change
KW  - Geomagnetic jerks
KW  - Correlation based modelling
Y1  - 2017
U6  - https://doi.org/10.1016/j.pepi.2017.05.017
SN  - 0031-9201
SN  - 1872-7395
VL  - 276
SP  - 145
EP  - 158
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Brown, Maxwell C.
A1  - Donadini, Fabio
A1  - Nilsson, Andreas
A1  - Panovska, Sanja
A1  - Frank, Ute
A1  - Korhonen, Kimmo
A1  - Schuberth, Maximilian
A1  - Korte, Monika
A1  - Constable, Catherine G.
T1  - GEOMAGIA50.v3: 2. A new paleomagnetic database for lake and marine sediments
JF  - Earth, planets and space
N2  - Background: GEOMAGIA50.v3 for sediments is a comprehensive online database providing access to published paleomagnetic, rock magnetic, and chronological data obtained from lake and marine sediments deposited over the past 50 ka. Its objective is to catalogue data that will improve our understanding of changes in the geomagnetic field, physical environments, and climate.
 Findings: GEOMAGIA50.v3 for sediments builds upon the structure of the pre-existing GEOMAGIA50 database for magnetic data from archeological and volcanic materials. A strong emphasis has been placed on the storage of geochronological data, and it is the first magnetic archive that includes comprehensive radiocarbon age data from sediments. The database will be updated as new sediment data become available.
 Conclusions: The web-based interface for the sediment database is located at http://geomagia.gfz-potsdam.de/geomagiav3/SDquery.php. This paper is a companion to Brown et al. (Earth Planets Space doi:10.1186/s40623-015-0232-0,2015) and describes the data types, structure, and functionality of the sediment database.
KW  - Geomagnetism
KW  - Paleomagnetism
KW  - Sediment magnetism
KW  - Rock magnetism
KW  - Environmental magnetism
KW  - Database
KW  - GEOMAGIA50
Y1  - 2015
U6  - https://doi.org/10.1186/s40623-015-0233-z
SN  - 1880-5981
VL  - 67
PB  - Springer
CY  - Heidelberg
ER  -