A battle with fog banks
around the polar light
show
2:20 CET: The view from
Lugberg/Germerswang looking north...
Nothing happens. O.k, the solar storm
takes its time. Fog!, change of
location to the other side.
2:50: Still no
aurora. Fog is coming up here too.
It's pointless, so off home. But
suddenly, a brief intense red shining,
a polar light appeared through the
mist. Arrival time exactly predicted
by
SWPC,
Wow!
3:00h: The fast change of location towards
Galgen/Mammendorf, no fog! And now the
aurora borealis actually appeared along
with the power line intended for
connecting the aurora ;-)
3:10h:
On the left in the background is the village of
Mammendorf. Fog is rolling in again, frustrating!
3:30h: Again change of location to the
wind turbine Mammendorf. An annoying bank of fog
builds up again in front of me.
4:30: Change of location near Landsberiet. Now
finally a clear view!
4:40: Shortly before dawn, the strongest
aurora borealis rays appeared.
4:50h CET:
The appearance was clearly visual.
KP index of approx.
8+
What a foggy thriller at 1°C.
Basics about
sightings of Aurora Borealis also known as Northern- or polar lights,
in middle latitudes
KP index*:
Roughly speaking, auroras can already be observed visually from
KP 5-6 (G1/2 storm)
in northern Germany. At
KP 7/8 (G3/4 storm)
or above
also in southern Germany (Alps to southern Europe). Among
other things, the density and speed of the flares or CME's
(earth directed solar mass ejection forms) or corona holes are relevant
parameters for the strength of the solar storms and visual
sightings. But the Bz value
which definite the north- south alignment of the
earth magnetic field ( May 2024, Bz -50nT ) is the most important factor.
If this Bz value
is to weak, the protons can't invade in the earth magnetic
field. By the way, the glowing phenomenon is triggered by
'animated' oxygen and nitrogen atoms. Oxygen up to ~100 km
shows
greenish
colors and from
~100-200 km
red to orange.
Nitrogen atoms up to ~300 km
shows more seldom purple
or blue
colors.
NOAA Space
Weather
Prediction Center
Aurora Borealis & Atmospheric phenomena
