Tuesday, 21 February 2012

Last Days

Today is the last day for me at Princess Elisabeth station. Tomorrow we will fly to the Russian Novo Air Base and on Thursday then to Cape Town. The last days are filled with de-installing the instruments which have to go back to Belgium for calibration or adaption reasons, and to prepare the other instruments for winter operation. All my instruments have been measuring fine so far, so I am right away satisfied. There was a lot of sunny weather, and the ozone spectrophotometer and the sun photometer had done a lot of good measurements. Also the condensation particle counter (measuring the number of particles in the air) turned out to behave smoothly. Most of the time there are low particle concentrations of around 300 to 500 particles per cubic centimetres. If one would measure, e.g., in Brussels, the concentrations were 100 to 1000 times higher. Our instrument is really sensitive – detecting immediately if the station’s bulldozer, tractor or somebody smoking is passing nearby. The last days we take advantage of the calm weather for clearing the garage’s roof from the huge amount of snow/ice which has accumulated over the last winter. We were moving tons of snow/ice. One block of around 50x50x50 cm of this compacted snow weighs approximately 70 to 80 kg. On Sunday I also went with Denis from the Observatory to dig a 1 m snow profile in order to better understand the snow accumulation over the winter. These measurements are needed for the ‘Hydrant’ project of the KU Leuven, from whom nobody could come this season. At such a profile one measures the temperature profile, determines how many layers are distinguishable, and within these layers one describes the ice crystals size, form and the hardness of the snow. In addition, from the layers snow samples are taken in a normed cylinder and this is weighed. This weight is then converted in water equivalent and is then used to estimate the amount of precipitation over the accumulation period. On the images, the Utsteinen nunatak and the station on the small Utsteinen ridge can be seen. On Monday, we got a bit more wind and this was announced earlier by the forms the clouds form over the Romnoesfjellet peak towards north, around 60 km from Princess Elisabeth station.

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