Free Newsletters - Space - Defense - Environment - Energy - Solar - Nuclear
..
. 24/7 Space News .




EARTH OBSERVATION
Rapid changes in the Earth's core: The magnetic field and gravity from a satellite perspective
by Staff Writers
Munich, Germany (SPX) Oct 23, 2012


Illustration only.

Annual to decadal changes in the earth's magnetic field in a region that stretches 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 a German-French group of geophysicists in the latest issue of PNAS (Proceedings of the National Academy of Sciences of the United States).

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. 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.

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.

A satellite only measures the total gravity, which consists of the mass fractions of Earth's body, water and ice on the ground and in the air. To determine the mass redistribution by flows in the outer core, the thus attained share of the total gravity needs to be filtered out.

"Similarly, in order to capture the smaller changes in the outer core, the proportion of the magnetic crust and the proportion of the ionosphere and magnetosphere need to be filtered out from the total magnetic field signal measured by the satellite," Vincent Lesur explains. The data records of the GFZ-satellite missions CHAMP and GRACE enabled this for the first time.

During the investigation, the team focused on an area between the Atlantic and the Indian Ocean, as the determined currents flows were the highest here. Extremely fast changes (so-called magnetic jerks) were observed in the year 2007 at the Earth's surface.

These are an indication for sudden changes of liquid flows in the upper outer core and are important for understanding the magneto-hydrodynamics in the Earth's core. Using the satellite data, a clear signal of gravity data from the Earth's core could be received for the first time.

This results in consequences for the existing conceptual models. Until now, for example, it was assumed that the differences in the density of the molten iron in the earth's core are not large enough to generate a measurable signal in the earth's gravitational field. The newly determined mass flows in the upper outer core allow a new approach to Earth's core hydrodynamics.

"Recent changes of the Earth's core derived from satellite observations of magnetic and gravity fields", Mioara Mandea, Isabelle Panet, Vincent Lesur, Olivier de Viron, Michel Diament, and Jean-Louis Le Mouel, PNAS 2012; doi:10.1073/pnas.1207346109

.


Related Links
Helmholtz Association of German Research Centres
Earth Observation News - Suppiliers, Technology and Application






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





EARTH OBSERVATION
TerraSAR-X images Bonneville salt flats
Berlin, Germany (SPX) Oct 22, 2012
Clouds, darkness, rain - the radar 'vision' of TerraSAR-X is unaffected by these conditions. Dark and light areas contrast clearly in this image, acquired by the German Aerospace Center's (Deutsches Zentrum fur Luft- und Raumfahrt; DLR) TerraSAR-X satellite. The black areas represent water, where radar signals transmitted by the satellite are not returned, as they are reflected away by the ... read more


EARTH OBSERVATION
European mission to search for moon water

Model reconciles Lunar Earth composition with giant impact theory

Massive planetary collision may have zapped key elements from moon

Proof at last: Moon was created in giant smashup

EARTH OBSERVATION
Valles Marineris - the largest canyon in the Solar System

Curiosity Rover Collects Fourth Scoop of Martian Soil

How Space Station Can Help Humans Follow Curiosity to Mars and Beyond

Mars Soil Sample Delivered for Analysis Inside Rover

EARTH OBSERVATION
NASA must reinvest in nanotechnology research, according to new Rice University paper

Austrian space diver no stranger to danger

Baumgartner feat boosts hopes for imperilled astronauts

Austrian breaks sound barrier in record space jump

EARTH OBSERVATION
Patience for Tiangong

China launches civilian technology satellites

ChangE-2 Mission To Lagrange L2 Point

Meeting of heads of ESA and China Manned Space Agency

EARTH OBSERVATION
New ISS Crew Confirmed

Russia launches three astronauts to ISS

ISS Orbit to be Adjusted for Next Spacecraft

Crew Unloads Dragon, Finds Treats

EARTH OBSERVATION
Brazil eyes closer space cooperation with Ukraine

S. Korea plans third rocket launch bid Friday

AFSPC commander convenes AIB

Proton Lofts Intelsat 23 For Americas, Europe and Africa Markets

EARTH OBSERVATION
New small satellite will study super-Earths for ESA

Most Planetary Systems are 'Flatter than Pancakes'

Glitch could end NASA planet search

Ultra-Compact Planetary System Is A Touchstone For Understanding New Planet Population

EARTH OBSERVATION
Angkor Wat builders may have had shortcut

Taking aim at rivals, Apple unveils iPad mini

Japan firm launches real-time telephone translation

Microsoft gives peek at new Windows, tablet




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement