Difference of the Geomagnetic Variations in Wingst and Niemegk in the last 24 hours

Shown here is the difference between the variations of horizontal intensity (H), declination (D) and vertical intensity (Z) at the observatories Niemegk and Wingst. Addition of the difference between a moving average values gives the absolute differences.

The average absolute difference is approximatly the difference of field contributions from inside the Earth: the slowly varying main field originating in the Earth's outer core and local, constant field contributions due to magnetized rocks in the Earth's crust (crustal field).

Differences in the variations reflect the inhomogeneity of the field contributions with sources external to Earth in the ionosphere and magnetosphere. During magnetically quiet times the differences vary only slightly as the fields are close to homogeneous over the distance Niemegk - Wingst. During magnetically disturbed conditions the differences can vary with considerable amplitudes. In particular geomagnetic storms show large inhomogeneity.

The differences have different information content in the individual components. Horizontal intensity is most directly influenced by the external field contributions. Variations in vertical intensity are strongly influenced by the electrical conductivity of the subsurface and contain information on the field contributions induced in the Earth by the external variations.

Strong short-period differences in Z between Niemegk and Wingst often are a result from the fact that variations of certain periods have the opposite sign at the two observatories in this component. The different behaviour of horizontal and vertical components can be used to study the conductivity distribution inside the Earth, for example by magnetotellurics.

The values shown here are calculated from uncorrected measurement results. Sporadically artificial disturbances (i.e. erroneous values) might occur, which will only be corrected in the final data sets later on. Such irregular errors may be able to distort the scaling.


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Dr. Jürgen Matzka

Lindenstr. 7
Building H 1, room 101
14823 Niemegk
tel. +49 33843 624-18