Rapid Changes in the Earth's Core: The Magnetic Field and Gravity from a Satellite Perspective

'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.'

'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.'

' Extremely fast changes (so-called magnetic jerks) were observed in the year 2007 at 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 Earth's core. '

Here's the story from 2008 where they first mentioned it, [link to www.sciencedaily.com] So, it appears it took them about 4 years to determine how to measure the change.

Changes in Earth’s gravity in relation to magnetic field measured
Posted on October 23, 2012 by Anthony Watts
[link to wattsupwiththat.com]

Good post, new currents promote new fields. If these new fields are shifted away from the dominant field they detract away from the overall magnetic field force. this is apparently happening, but at what rate? we watch and wait!
Nice thread T!

Here's the Paper [link to www.pnas.org] and 2 Videos showing;
"One of the most puzzling features of the magnetic field revealed by the study of satellite data is the evidence of a rapid evolution in time of its second order time derivative (the secular acceleration) (2, 4). As shown in the animation (Movie S1), the acceleration computed at the Earth’s surface evolves smoothly
over the last decade. It is roughly characterized by a patch of acceleration migrating from India around 2003 to the southwest of the Indian Ocean in 2008, while a strong patch of deceleration grows in the middle Atlantic to reach a maximum in 2006 and then vanishes rapidly (2)."
[link to www.pnas.org]

"To maximize the core signals-to-other sources ratio, we have corrected for estimated annual, semiannual, and 161 d periodic cycles. As the core signals are large-scale patterns, we have truncated the GRACE gravity models at degree and order 8, corresponding to a spatial resolution of 2500 km. This also removes
most of the striping patterns. Our postprocessed models mostly contain imperfectly modeled seasonal variations, and interannual signals such as polar ice caps mass variations. They are represented in the supplemental animation file (Movie S2)."
[link to www.pnas.org]

At [link to www.pnas.org]