Sunday, 12 February 2012

Work and Weather

Last days we had two minor storms, the first on Thursday and the second on Friday to Saturday. They were not really strong, but strong enough that the Utsteinen Nunatak was barely or not visible anymore. On the bottom photo you can imagine the snow drifting or blowing across the ridge on which the station and the aerosol instrument shelter is located. When the visibility becomes bad like this, you better stay inside and only the really necessary and essential tasks outside can be done. On Saturday morning already, wind became less, and around noon wind was weak and we had a nice sunny day again. It is fascinating to watch then how the wind has formed the snow and ice surface. You can easily walk a long time around, just watching the ground and the diverse shapes the storm has left. Today, there is a cirrus stratus layer above us and a nice Halo could be seen (top image). This optical phenomenon is caused by the refraction of light, under a certain angle, on ice crystals within these clouds.

On Saturday, I installed the last instrument I brought with me – an ultrafine condensation particle counter. This instrument measures how many particles there are in the atmosphere, from the very tiny ones to coarse particles. For an atmospheric researcher like me, very tiny means around a few nanometres (that is one billionth of a meter), and coarse would be a particle of 2 or 3 micrometres (what is in fact still very small). For comparison, a typical cloud droplet is around 20 micrometres and a rain drop about 2 millimetres. With all aerosol instruments now running, we have a comprehensive description of the physical and optical properties of the atmospheric particles in this part of Antarctica. It is now the aim to let as much as possible of all the instruments running over winter. Therefore, I will do some checks and preparations with the instruments in the coming days.

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