MessageToEagle.com
23 October, 2012
MessageToEagle.com - Rapid, almost sudden, changes take place in the Earth’s magnetic field.
A German-French group of geophysicists observed that - changes in the earth's magnetic field in a region stretching from the Atlantic to the Indian Ocean - have a close relationship with variations of gravity in this area.
From this it can be concluded that outer core processes are reflected in gravity data. This is the result presented by scientists in the latest issue of PNAS.
The main field of the Earth's magnetic field is generated by flows of liquid iron in the outer core. The Earth's magnetic field protects us from cosmic radiation particles.
Click on image to enlarge
http://www.pnas.org/content/suppl/2012/10/11/1207346109.DCSupplemental/pnas.1207346109_SI.pdf
Therefore, understanding the processes in the outer core is important to understand the terrestrial shield. Key to this are measurements of the geomagnetic field itself.
A second, independent access could be represented by the measurement of minute changes in gravity caused by the fact that the flow in the liquid Earth's core is associated with mass displacements.
The research group has now succeeded to provide the first evidence of such a connection of fluctuations in the Earth's gravity and magnetic field.
Click on image to enlarge
http://www.pnas.org/content/suppl/2012/10/11/1207346109.DCSupplemental/pnas.1207346109_SI.pdf
They used magnetic field measurements of the GFZ-satellite CHAMP and extremely accurate measurements of the Earth's gravity field derived from the GRACE mission, which is also under the auspices of the GFZ.
"The main problem was the separation of the individual components of the gravity data from the total signal," explains Vincent Lesur from the GFZ German Research Centre for Geosciences, who is involved in the study.
Simulated three-dimensional structure of Earth's magnetic field, with inward (blue) and outward (yellow) directed field lines. Field lines extend two Earth radii from the core. The location of the core-mantle boundary is evident where the structure becomes complex. Credits: G. Glatzmaier, Los Alamos National Laboratory. P. Roberts, University of California-Los Angeles
For full article:Rapid Changes In The Earth's Core - The Magnetic Field And Gravity Seen By Satellites - MessageToEagle.com
