Aerogeophysics in Finland 1972-2004 - arkisto.gsf.fi - Geologian ...

at the Geophysical Observatories in Nurmijärvi,
South Finland, and Sodankylä, North Finland.
In the second phase, the data is gridded and the
DGRF1965.0 reference field (Fig. 24) is removed.
After removal of DGRF1965.0, the standard deviation
of the Finnish magnetic anomaly field is about
300 nT and thus the anomaly maps can be combined
using the same colour table for the whole country.
Other corrections
A lag test is performed to verify the recording delay.
Due to the real time RMS compensation, its prefiltering,
and delays in network data transmission, a
small lag exists in the recording of the data. This is
verified by repeating a flight line in opposite directions
above a sharp but sideways wide magnetic
Fig. 22. A set of diurnal variation recordings in Finland: quiet day, moderate
variation, strong variation.
Geological Survey of Finland, Special Paper 39
The “Three-in-One” aerogeophysical concept of GTK in 2004
Fig. 23. The secular variation in Finland during the Second National
Mapping Project. Measured at the Nurmijärvi Geophysical Observatory
by Finnish Meteorological Institute, Southern Finland and in Sodankylä
Geophysical Observatory by University of Oulu, Northern Finland.
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