Monday, 11 March 2013

Winter season 2013 has started

After the last team left Princess Elisabeth station (visit the station blog, the station and also its scientific instrumentation is now completely in automatic and remote control mode. Until now, all instruments have continuously been working and are doing this also right now. The sunphotometer and the Brewer spectrophotometer however, have been dismounted end of February by Erik. The sunphotometer travels back to Europe for the yearly calibration and the Brewer is stored inside the station. In principle, it could be operated continuously, but as its optical part is very sensitive it would be too risky to leave it running. If anything happened to the instrument’s mechanics or optics, there would be nobody to repair it. This will possibly damage the whole instrument and repair or replacement would be an immense cost. All the six other instruments will continue to record and send data, as long as there is no power break down or failure of an instrument part. In the southern scientific shelter, the five aerosol instruments (TEOM-FDMS aethalometer, nephelometer, laser aerosol spectrometer, condensation particle counter) are now in their forth month of simultaneous operation. The condensation particle counter has got his larger reservoir for n-butanol supply during the long winter period, and the nephelometer has been calibrated a last time before the end of the season. Such a calibration is done with a pure reference gas, in our case extremely pure carbon dioxide. The amazing thing of remote control is that I could do some nephelometer calibration from my desk in Brussels. This needed of course some cooperation with Erik at the station who opened the gas bottles and some valves, but the exact calibration I controlled via remote desktop connection to the controlling desktop in the shelter which in turn is connected via a serial port to the nephelometer control port. As it is too risky to leave an open gas bottle nine months unattended, a full calibration will not be possible anymore. But a so-called zero-check (with ‘zero’, filtered air via an internal filter) of the calibration regression can always be done remotely. In the next entry to this blog I will show some exemplary graphs of the aerosol data. The images above show the instruments at the end of the season: the Brewer spectrophotometer and the elevated box with sensors for total solar and UV-A, UV-B irradition on the northern station roof; the Cimel sunphotometer; and the five aerosol instruments in southern shelter (order from left to right like mentioned above).