Mass motion in the Earth’s core and mantle and their influence on polar motion
Mass motions in the Earth’s interior cause variations of polar motion and the gravity field. In this project, geophysical phenomena connected with the Earth core and mantle will be investigated, in particular for the decadal and sub-decadal time scale – a scale range, which is important for the objectives of the DFG research unit. The objectives of this project are (i) an improved modelling of core-mantle coupling and inner-core motions to better understand the applied geophysical processes and to solve the present discrepancies between predicted and observed values of polar motion variations, and (ii) to check whether the density variations and/or mass redistributions accompanying these processes are large enough to be detectable in the gravity field.
Involved institutions:
Scientists / Staff:
- Dr. Hans Greiner-Mai, GeoForschungsZentrum GFZ,
Tel.: +49 331 288 1144, E-Mail: grm (at) gfz-potsdam.de - Dr. Jan Hagedorn, GeoForschungsZentrum GFZ,
Tel.: +49 331 288 1750, E-Mail: jan (at) gfz-potsdam.de
Publications:
- Hagedoorn, J.M., Greiner-Mai, H. & Ballani, L.: Determining the time-variable part of the toroidal geomagnetic field in the core-mantle boundary zone. Phys. Earth Planet. Inter., doi:10.1016/j.pepi.2009.07.014, in press, 2009.
- Hagedoorn, J.M. & Geiner-Mai, H.: Core-Mantle Coupling - Part I: Electromagnetic coupling torques. Sci. Techn. Rep. GFZ Potsdam, STR 08/06, doi:10.2312/GFZ.b103-08061, ISSN 1610-0956, 2008
(or http://bib.gfz-potsdam.de/pub/str0806/0806.pdf). - Greiner-Mai, H. & Hagedoorn, J.M.: Core-Mantle Coupling - Part II: Topographic coupling torques. Sci. Techn. Rep. GFZ Potsdam, STR 08/06, doi:10.2312/GFZ.b103-08113, ISSN 1610-0956, 2008
(or http://bib.gfz-potsdam.de/pub/str0811/0811.pdf). - H. Greiner-Mai, J. Hagedoorn, L. Ballani, I. Wardinski, D. Stromeyer, & R. Hengst: Axial poloidal electromagnetic core-mantle coupling torque: a re-examination for different conductivity and satellite supported geomagnetic field models. Studia Geophysica at Geodaetica 51, 491–513, 2007.
Poster Presentations:
- J.M. Hagedoorn, H. Greiner-Mai, L. Ballani, D. Stromeyer & I. Wardinski: Combined coupling torques for the electromagnetic and topographic core-mantle coupling and their influence on Earth's rotation. EGU General Assembly 2009, April 19 – 24, 2009.
Download (pdf/4629 KB) - J.M. Hagedoorn, H. Greiner-Mai, L. Ballani, D. Stromeyer & I. Wardinski: Determination of the electromagnetic and topographic core-mantle coupling torques based on geomagnetic observations: Influence of the electric conductivity of the Earth's mantle. AGU 2008 Fall Meeting, San Francisco, December15–19, 2008. Download (pdf/2792 KB)
- J.M. Hagedoorn, H. Greiner-Mai, L. Ballani, D. Stromeyer & I. Wardinski: Investigating the time lag in the electromagnetic core-mantle coupling torque due to different radial conductivity profiles. 11th Symposium of SEDI, Kunming P.R. China, July 26 – 31, 2008. Download (pdf/1241 KB)
- J.M. Hagedoorn, H. Greiner-Mai, L. Ballani & D. Stromeyer: Determination of the toroidal geomagnetic field in the lower mantle considering a radial electric conductivity profile. EGU General Assembly 2008, 14-18 April, Vienna.
Download (pdf/3095 KB) - J. M. Hagedoorn, H. Greiner-Mai, L. Ballani, & I. Wardinski:
Electromagnetic core-mantle coupling torques for different magnetic field models and core velocity fields. Poster presentation, IUGG XXIV General Assembly, Perugia, Italy, July 2 – 13, 2007. Download (pdf/482 KB)
Oral Presentations:
- J.M. Hagedoorn, H. Greiner-Mai, L. Ballani, D. Stromeyer & I. Wardinski: Influence of highly electrically conducting post-perovskite on the geomagnetic field and the electromagnetic core-mantle coupling torque at the CMB. Workshop "Transport Properties of the Lower Mantle", October 21 - 24, 2008, Yunishigawa, Japan.
- J.M. Hagedoorn, H. Greiner-Mai, L. Ballani, D. Stromeyer & I. Wardinski: Influence of the electric conductivity profiles of the lower mantle on the electromagnetic core-mantle coupling torque. EGU General Assembly 2008, 14-18 April, Vienna.
- H. Greiner-Mai: Topographische Kern-Mantel Kopplung - analytische Kopplungsdrehmomente. Statusseminar DFG Forschergruppe FOR 584 “Erdrotation und globale dynamische Prozesse”, Wettzell, 12. – 14.03.2008.
- J. Hagedoorn: Elektromagnetische Kern-Mantel Kopplung - das Problem der bestimmung des toroidalen Magnetfeldes. Statusseminar DFG Forschergruppe FOR 584 “Erdrotation und globale dynamische Prozesse”, Wettzell, 12. – 14.03.2008.
- J. Hagedorn: Zwischenbericht zur Drehmomentbestimmung der elektromagnetischen Kern-Mantel-Kopplung. Statusseminar DFG Forschergruppe FOR 584 “Erdrotation und globale dynamische Prozesse”, Dresden, 30. – 31.05.2007.
- H. Greiner-Mai, L. Ballani, D. Stromeyer, J. Hagedoorn, & R. Hengst:
Electromagnetic core-mantle coupling torques for different conductivity models of the core-mantle transition zone. 10th Symposium of SEDI, Prague, Czech Republic, July 9 – 14, 2006.