Tuesday, 8 April 2014

Making measurements

As soon as we arrived, we got to work building the set up for our experiment. Just as we had practiced in Qaanaaq we assembled the antenna frame, arranged the Network Analyser in its thermal box and mounted everything on the sled. It took a while in the afternoon to get the generator working but that first day we worked until about 10pm and got the first few radar shots done. The sun didn’t 'set' until about 1am, and it never really got dark so it was very easy to keep on working until late.


30th March - Today was a bit trickier. On site we had 3 generators and for some reason - possibly the cold, possibly because they had been shaken around a bit too much in transit – none of them wanted to run for any extended period of time! This was also the day that the rest of the ground team went on a day excursion to a northern site and Ewan came to the ice camp to help us make measurements. Luckily it wasn’t a wasted day as we made a load of snow depth measurements, and the generator eventually started working so we managed to make some radar shots late in the evening.

31st March – we had a really good day. We managed to get one of the generators to run for a whole day non-stop! Taking our radar shots of the sea ice and digging the snow pits to make notes about the snow layer characteristics quickly became a routine and we got really efficient at using our time effectively, so that neither of us was stood around for too long getting cold. The time absolutely whizzed by and we ended up working from the morning all the way through until about 10pm.

In the afternoon the weather set in a bit again. The wind picked up and it began to snow. It wasn’t too cold though – the combination of the low cloud and fresh snow meant that the temperature stayed reasonably high (when it was still with clear skies the air temperature could get down to -30C to -35C). The cloud and snow also meant that the visibility dropped significantly, from 10s of kilometres to a few hundred meters. We were working at the second corner reflector site, about 300m from the camp and when the visibility dropped we got quite paranoid about polar bears – we were stopping and checking around every few minutes. We had our whistles to attract the attention of Marc and Petter, and if it really got close we also had some bear bangers (small fireworks that you launch off a pen-sized device) to put off any curious bears. Here you can see how low the visibility can get with even mild wind and snow:

An interesting atmospheric effect also happens when there are ice crystals in the air - the suns light gets refracted and forms a ring around the sun, commonly known as a 'sundog'. Here's a pic:

We made a lot of measurements, and dug a lot of snow pits. It sure makes your back ache! But we got a really god idea of the variability of the snow layer on top of the sea ice. This is important for us because understanding how the radar interacts with the snow layer is essential for making the best measurements with the CryoSat-2 satellite.

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