TY  - GEN
A1  - Lesur, Vincent
A1  - Wardinski, Ingo
A1  - Asari, Seiki
A1  - Minchev, Borislav
A1  - Mandea, Mioara
T1  - Modelling the Earth's core magnetic field under flow constraints
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
N2  - Two recent magnetic field models, GRIMM and xCHAOS, describe core field accelerations with similar behavior up to Spherical Harmonic (SH) degree 5, but which differ significantly for higher degrees. These discrepancies, due to different approaches in smoothing rapid time variations of the core field, have strong implications for the interpretation of the secular variation. Furthermore, the amount of smoothing applied to the highest SH degrees is essentially the modeler’s choice. We therefore investigate new ways of regularizing core magnetic field models. Here we propose to constrain field models to be consistent with the frozen flux induction equation by co-estimating a core magnetic field model and a flow model at the top of the outer core. The flow model is required to have smooth spatial and temporal behavior. The implementation of such constraints and their effects on a magnetic field model built from one year of CHAMP satellite and observatory data, are presented. In particular, it is shown that the chosen constraints are efficient and can be used to build reliable core magnetic field secular variation and acceleration model components.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 844 
KW  - Geomagnetism
KW  - core field modeling
KW  - core flow modeling
KW  - frozen-flux
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-430369
SN  - 1866-8372
IS  - 844
SP  - 503
EP  - 516
ER  - 
TY  - GEN
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
BT  - 2. A new paleomagnetic database for lake and marine sediments
T2  - Postprints der Universität Potsdam : Mathematisch Naturwissenschaftliche Reihe
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.
T3  - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 875 
KW  - Geomagnetism
KW  - Paleomagnetism
KW  - Sediment magnetism
KW  - Rock magnetism
KW  - Environmental magnetism
KW  - Database
KW  - GEOMAGIA50
Y1  - 2020
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-434768
SN  - 1866-8372
IS  - 875
ER  -