K is the daily sum of the eight K numbers.
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:
http://www-app3.gfz-potsdam.de/obs/niemegk/monrep/,
while earlier months are available via FTP:
ftp://ftp.gfz-potsdam.de/pub/home/obs/monrep/
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 |
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 aK using the following table:
|
Range of ak
|
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 |
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.
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