Geomagnetic secular variation since 1901

Four centuries of geomagnetic secular variation from historical records

We present a new model of the magnetic ­ eld at the core{mantle boundary for the interval 1590{1990. The model, called gufm1, is based on a massive new compilation of historical observations of the magnetic ­ eld. The greater part of the new dataset originates from unpublished observations taken by mariners engaged in merchant and naval shipping. Considerable attention is given to both correcti...

Polynomial Modelling of Southern African Secular Variation Observations Since 2005

The COMPASS (COmprehensive Magnetic Processes under the African Southern Sub-continent) program forms part of a collaboration project between Germany and South Africa, called Inkaba ye Africa, and aims to investigate the regional geomagnetic field in this area, particularly its evolutionary behaviour. Results obtained from field surveys conducted by the Hermanus Magnetic Observatory (HMO) and ...

Fractal Analysis for Geomagnetic Secular Variations

Investigation of a secular variation impulse using satellite data: The 2003 geomagnetic jerk

Observatory monthly means provide an excellent opportunity to study the temporal changes of the magnetic field at a given location. Unfortunately, the uneven distribution of the present observatory network makes it difficult to determine the global field change pattern. Recently, we have developed an approach to extract satellite monthly means at a regular network of “virtual observatories” at ...

High-resolution record of geomagnetic secular variation from Late Pleistocene Lake Lisan sediments (paleo Dead Sea)

We measured geomagnetic secular variation in Lake Lisan sediments (paleo Dead Sea). More than 1500 oriented samples were collected from a 27.3-m section of alternating aragonite and detritus laminae in the Dead Sea basin ranging in age from 67 to 32 ka. The natural remanent magnetization (NRM) is carried by titanomagnetite in the detrital laminae whereas the aragonite is diamagnetic. The NRM is...