Today on 7 December we have launched our 10th
balloon with the new system and we got as usual good data on the vertical
distribution of temperature, humidity, wind and pressure up to 32 km altitude
(however, it needs to be said that humidity is only reliable up to around 10
km). All launches have been good until now and we are happy that we are able to
create a database of the meteorological and dynamic conditions in the higher
atmosphere around Princess Elisabeth station. To launch such a weather balloon
it is necessary to be with two. One prepares the radiosonde which measures and
transmits the data and the other holds the with Helium filled balloon until
launch. At some days the wind has been very strong and it was not always easy
to hold the balloon until the sonde is ready and is fixed to the balloon. During
strong winds at launch time, the balloon bounces back and forth and tries to
escape …
All the instruments we have set up are used to follow the
evolution of aerosol (particle) properties around Princess Elisabeth station.
Most of the time the conditions are relatively constant and not much special is
happening. But, yesterday – we went to check routinely our instruments – we saw
that the particle concentration was increasing. From the normal baseline of
200-300 particles/cm3 during summer it went suddenly up to 6000 / cm3.
It happened during strong winds from eastern directions and contamination by
the station can surely be ruled out. It is more probable that this was linked
to the approaching of a major cloud system. The lower cloud level was
decreasing when the particle concentration went up. When the concentration
reached maximum and thereafter, the cloud level was increasing and the clouds
even move away. The instrument from Leipzig told us that the concentration of
particles being able to form clouds has not much increased during this event.
So, there are some questions for us to be answered, how clouds, the whole lot
of particles and particles, which can form clouds, are linked. That’s why we
are here. This morning the concentration of particles was again at the usual
level around 300 / cm3. And no strong winds anymore.
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