Core field acceleration pulse as a common cause of the 2003 and 2007 geomagnetic jerks
Abstract
Using observatory data, we report the detection of a
geomagnetic jerk in 2007, which we relate to a jump in
the second derivative of the geomagnetic field previously
noted in satellite data. Although not of worldwide extent,
this jerk is very intense in the South Atlantic region.
Using the CHAOS‐2 model, we show that both this jerk
and the previous 2003 jerk are caused by a single core
field acceleration pulse reaching its maximum power near
2006.0. This pulse seems to be simultaneously occurring
in several regions of the core surface where it corresponds
to dominant n = 5 and 6 spherical harmonic modes.
Geometrical attenuation explains why the 2003 and 2007
jerks are local and not fully synchronized at the Earth’s
surface. Our results suggest that this core field acceleration
pulse is the relevant phenomenon to be investigated from
the point of view of core dynamics, rather than the jerks
themselves. Citation: Chulliat, A., E. Thébault, and G. Hulot
(2010), Core field acceleration pulse as a common cause of the
2003 and 2007 geomagnetic jerks
Origin : Publisher files allowed on an open archive
Loading...