Monthly Report
Adolf-Schmidt-Observatory Niemegk

Each month, the Adolf-Schmidt-Observatory Niemegk publishes a Monthly Report containing essential results from the previous month. The Monthly Reports are available in printed form as well as through the Internet. The results of the most recent month are presented
in Web format at:,
while earlier months are available via FTP:

Table 1  presents the magnetic activity indices calculated at Niemegk observatory. The eight three-hourly K numbers (after Bartels) are calculated by a computer code (FMI method) from the digital recordings of the three component flux-gate variometer FGE. They are hand-scaled in parallel from the photographic recordings of the classical variometers for comparison. The ranges of the individual K numbers are defined as follows:

Devitation from the
normal sq variation/nT
     < 5     5 ... < 10   10 ... < 20 20 ... < 40 40 ... < 70 70 ... < 120 120 ... < 200 200 ... < 330 330 ... < 500 > 500    
K 0 1 2 3 4 5 6 7 8 9

sigma K is the daily sum of the eight K numbers.

To derive the local equivalent daily amplitude AK, a three-hourly equivalent amplitude aK is assigned from each K value using the following table:

K 0 1 2 3 4 5 6 7 8 9
aK 0 3 7 15 27 48 80 140 240 400

AK is then the mean value of the eight aK numbers, measured in units of 2nT.

The daily character-figures C (after A. Schmidt) and F (after G. Fanselau) are defined by sigmaaK using the following table:

Range of sigmaak C F
   0 ...     24 0 0.0
  25 ...   120 0 0.5
121 ...   216 1 0.5
217 ...   384 1 1.0
385 ...    640 1 1.5
641 ...   1120 2 1.5
     > 1120 2 2.0

kappa represents the degree of variability of geomagnetic disturbances during a day. It is calculated by summing the absolute values of the differences in adjacent K values within one day. It also takes into account the last K value of the previous day and the first K value of the following day, by averaging these two differences, rounding fractions up or down to the nearest even number.

Table 2  gives typical variations detected in Niemegk from the magnetic recordings. b, bp, bs, bps, si, si*, ssc and ssc* are caused by solar corpuscular radiation, while sfe is an effect of solar wave radiation.
The typical variations b, bp, bs, bps, si, si*, ssc and ssc* are classified as A, B or C following international convention.

Diagram 1 shows in 3 separate diagrams plots of the hourly mean values of the magnetic north, east and vertical field components, also printed in table 3.

In Table 3 (a collection of 6 separate tables), preliminary hourly mean values of the magnetic elements X , Y and Z are published. These values are based on the digital recordings of the three-component fluxgate magnetometer FGE. The preliminary baseline of this magnetometer is determined from absolute measurements with a DI-flux theodolite and an Overhauser proton magnetometer.

In printed form, the monthly reports are available from:

GeoForschungsZentrum Potsdam
Adolf-Schmidt-Observatorium für Geomagnetismus
Lindenstraße 7
D-14823 Niemegk

For content questions please contact:

Jürgen Matzka
Helmholtz Centre Potsdam
GFZ German Research Centre for Geosciences
Public Law Foundation State of Brandenburg
Telegrafenberg, 14473 Potsdam

URL: index.html
Revised: Thu Jan 18 11:14:55 MET 2001