Magnetic Observatory Haimhausen
Haimhausen, Germany · geographic coordinates: 48°18' N
11°33 E · geomagnetic coordinates (2017): 43.33°N
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(plots last generated: 05.12.2024 14:05)
Explain these plots!
A magnetic field is characterized by a vector in three-dimensional
space. Upon international agreement, the horizontal component towards North is termed X and the horizontal component towards
East is called Y. At this time, this magnetometer only measures the two horizontal components.
The absolute intensity (magnetic flux) of the geomagnetic field is just under 50000 nT on the Earth's surface. This magnetometer
can measure variations on the order of a few nT during quiet geomagnetic conditions. During extreme solar storms, variations of
up to 1500 nT can occur. Depending on the disturbance level, the magnetogram uses different scales identified by the background color
(white/yellow/amber/red), allowing for a quick recognition of disturbed conditions.
The scale on the vertical axis shows the intensity variation in nT, the horizontal axis shows UTC time.
This magnetometer is located in Haimhausen, about 15 km north of Munich, Germany.
It measures the horizontal components of the Earth's magnetic field.
The above magnetogram shows the
development of the local magnetic field and allows to draw conclusions
particularly on the probability of observing norther lights (aurora borealis)
at the location of the magnetometer. The data analysis is based of
self-developed python and perl code.
The magnetogram shows intensity variations
with time of the geomagnetic field in Viby. The rather small variations are primarily caused by the solar
wind, which continuously moves onto the Earth's magnetic field. Changes in its velocity, density and
magnetic orientation influence orientation and intensity of the geomagnetic field.
The disturbance of the magntic field can have a considerable effect on the distribution of
electrically charged molecules in the ionosphere (upper atmosphere) which gives rise to northern lights. The
magnetometer is able to measure effects much smaller than causing aurora, which makes it an interesting tool for
forecasting northern lights.
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The magnetogram A magnetogram shows the temporal evolution of the magnetic flux density of the Earth's magnetic field at its location:
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Bx:
change of the North-South component of the magnetic flux density:
the smaller Bx, the higher the probability for polar lights |
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By :
change of the East-West component of the magnetic flux density:
evening hours: the higher By,
the higher the probability for polar lights
morning hours: the smaller By,
the higher the probability for polar lights |
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Bz:
change of the vertical component of the magnetic flux density:
the higher Bz,
the higher the probability for polar lights |
Quelle: NOAA/NDGC |
Often, instead of Bx und By the
horizontal intensity BH (quadratic sum of
Bx and By) as well as the
magnetic declination D = arctan (By/Bx) is used.
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Strong disturbances caused by solar activity are usually seen in the
horizontal components of the magnetic field. The vertical component can
be used to infer the location of the electrojets. These electric currents
run along the auroral
ovals and are, give and take, responsible for all magnetic disturbances resulting from
magnetic substorms close to the surface. Hence changes in the vertical component represent
a good measure for the strength of local substorms.
More about K values and the auroral oval
The K index
is a measure of the maximum fluctuation of the horizontal magnetic
field component ΔBH in fixed three-hour intervals. It is a historically-grown historisch gewachsenes,
quasi-logarithmic measure of the occurrence probability for polar lights.
It is calculated as the difference of maximal and minimal magnetic field strength in
eight predefined 3-hour intervals per day.
The association of K values and disturbance size is
chosen dependent on the latitude of the magnetic observatory in a way
so that the statistical distribution of worldwide K values
is reached. This means that K is an universal measure for polar light probabilities, and also that
stations at higher (geomagnetic) latitudes require larger fluctuations to reach a given K level.
For a given disturbance of the geomagnetic field, K values remain combarable globally. This also
allows for computing a global, so-called planetary Kp Index (Kp Indices from 1868 on).
Disturbances on the K scale can roughly be translated in how
far south the auroral oval will reach according to this map. Basically, for disturbances
equivalent to K7 or greater (G3-level storms) there is a small chance for northern lights in southern Germany.
For a fair chance of observing northern lights in northern central Europe, a level of
K8 should be reached.
Only from K9
the chances for visible aurora in Southern Germany are high. It is a good idea to also consider local circumstances at other
magnetometers, like SAM Stockholm.
SAM Haimhausen measures the evolution of the x and y components
of the Earth's magnetic fields. As only the relative changes with respect to the values at 00:00 UTC are
regarded, an absolute calibration against long-term drifts of the instrument is not required.
To determine the K value, SAM Haimhausen uses this conversion, appropriate for latitudes on the transition between mid and high latitudes:
K value |
magnetic field disturbance
ΔBx |
color code |
magnetic field |
G value |
0 |
below 10 nT |
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quiet
| G0
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1 |
below 20 nT |
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2 |
below 40 nT |
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unsettled
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3 |
below 80 nT |
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disturbed
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4 |
below 140 nT |
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active
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5 |
below 240 nT |
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minor storm
| G1
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6 |
below 400 nT |
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moderate storm
| G2
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7 |
below 660 nT |
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strong storm
| G3
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8 |
below 1000 nT |
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severe storm
| G4
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9 |
exceeding 1000 nT |
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extreme storm
| G5
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This service is based on Simple Aurora Monitor, designed by the SAM project by Karsten Hansky and Dirk Langenbach.
Parts of the hardware have been generously donated by Ralf Pitscheneder and had been previously used at polarlichtinfo.de.
Running SAM_linux & SAManpy software by Robert Wagner, powered by python on Raspberry Pi
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