HR: 16:00h
AN: GP44A-01 INVITED     [Abstracts]
TI: Decadal to Millennial Changes in the Magnetic Pole Positions and Dipole
AU: * MANDEA, M
EM: mioara@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam, Telegrafenberg, Haus F, Potsdam, 14473 Germany
AB: The magnetic pole positions on decadal to milennial time-scales represent a key parameter in understanding the current behavior of the magnetic field. The north magnetic pole velocity has significantly increased, reaching some 40km/yr in 2001, the highest rate measured so far over the last century. Because of the dominantly dipolar axial characteristic of the field, it is expected that the south magnetic pole has been moving in a similar way. Surprisingly, as it will be shown, this is not the case. These observations, together with the decrease in the Earth's magnetic dipole intensity have triggered the idea of a possible polarity reversal. Geomagnetic data provided by observatories situated at high latitude, as well synthetic data obtained from geomagnetic models (gufm1 and cals7k) indicate that a polarity reversal is not a likely cause. It will also be shown that the pole positions can be used as a good indicator of field variations. Indeed, some phenomena clearly linked to core dynamics, as the geomagnetic impulses observed only in observatory data, are also reflected in the dip pole velocity changes.
DE: 1507 Core processes (1213, 8115)
DE: 1555 Time variations: diurnal to decadal
DE: 1560 Time variations: secular and longer
SC: Geomagnetism and Paleomagnetism [GP]
MN: Fall Meeting 2005