|Description:|| On the night of 8th March 2014, the Kilpisjärvi Atmospheric Imaging Receiver Array (KAIRA) was hit by a ferocious Arctic storm from the northwest. The two nearest meteorological stations (Kilpisjärvi and Saana) measured maximum gusts of 34.9 and 44.3 m/s respectively (= 126 and 159 km/h). The KAIRA site itself would have experienced a maximum speed somewhere between these two values.|
KAIRA uses LOFAR technology by ASTRON and has tile and aerial antennas like other LOFAR stations (although mounted differently to cope with Arctic conditions).
At around the moment of the peak of the storm, the westernmost tile antenna (H75) broke free from its anchor lines and was blasted across the high-band array. Debris from the tile then landed between the high- and low-band arrays, with fragments scattering through the low-band field causing additional damage.
The image above shows a map of the arrays, marking the location of the damage and has a plot in the top-right to show the wind speed and the moment of failure. The inset photographs from the top-left, going down then across are: a) using a snowmobile to gain access to the site, b) shoring timbers to protect the tiles adjacent to the missing tile, c) servicing tile anchors in bitter conditions, d) the remains of tile H75, and e) damaged aerials on the low-band field.
Makeshift repairs have now been carried out and KAIRA will run slightly impaired until summer when full access to the site can be achieved. Although the damage looks serious, it could have been a lot worse. We were saved further grief by heavy ice cover on the other tiles and packed snow around the aerials.
And during the storm and repair work, we continued observing!
More information and photographs can be found on the KAIRA web log.
|Copyright:||Sodankylä Geophysical Observatory|