Thursday, 27 February 2014

Princess Elisabeth Antarctica station now in winter mode


the final place taking off from Utsteinen - copyright International Polar Foundation
On Monday, 24 February around noon, all station team members left Utsteinen and flew out to Novo (see image of the station webcam above; www.antarcticstation.org). For the coming nearly 9 months, nobody will be at the station. Everything has been arranged in order to guarantee the functioning of the station and that the scientific instruments can be remotely controlled. Four aerosol instruments remain active in the southern shelter: the TEOM-FDMS, the aethalometer, the laser aerosol spectrometer (LAS; number size distribution of particles) and the condensation particle counter (CPC; aerosol total number). The sunphotometer (total atmospheric aerosol load) was uninstalled by Karel and it is now on its way back to us. It has to be calibrated each year by the reference centre of the network it belongs to (AERONET; aeronet.gsfc.nasa.gov) and because during winter the sun is missing for its direct sun measurements. In addition, the sensors for total solar irradiation and UV-A and UV-B radiation remain active (follow in near-real time the evolution of the UV index ). Also, the cloud condensation nucleus counter is on its way back to the Institute for tropospheric research in Leipzig, Germany. We have now two months of simultaneous data on aerosol number, size distribution and the aerosol’s capability to form cloud droplets. The analysis will give us more insight into the type of the aerosol, if there are dependencies of the cloud formation properties on meteorology or on air mass origin. To operate aerosol instruments without being able to do any physical maintenance during 8 to 9 months is a challenge. Luckily, the aerosol shelter is well-insulated and heated, thus the harsh conditions during winter should not be a problem. However, during periods of heavy storms with very strong snow drift, the instruments could get problems of, e.g., too many snow crystals sucked in via their air sample inlets. Therefore, two additional supervision tools were installed in the shelter: (i) a webcam (an example image above), to be able to see, e.g., if the instruments are still on, if any of the error-message LEDs of the instruments are lit, or if there is any snow intrusion; (ii) a remotely controllable power switch, via which we can switch off and on each instrument individually. This last one will be useful when, e.g., the data connection between desktop and CPC hung up itself, or when the automatic tape advance mechanism of the aethalometer is blocked for any reason. So, everything is setup for a successful winter measurement period and currently working fine. Credits for this go to Karel Moerman, who supervised the instruments during the last two months, to Erik Verhagen who helped me a lot during my stay at the station, and also to Alain Hubert and the whole station team for the support and the help in order to keep the instruments running.

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