Polar Radar for Ice Sheet Measurements
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Day 30 - June 4 2006
Finally, this was the day we had been looking for! Dennis and I put in our longest and most productive days of the trip and finished mapping the grid. The weather was perfect for Flade Isblink. It was bright and sunny, the winds were calm and the temperature hovered around 32 F all day. We got up before the rest of the camp, ate breakfast, ran some premapping tests on the radar and were out mapping by about 10:00 am.
One of our last runs with the accumulation radar. Dennis is manning the sled, Claude is driving.
First we remapped the 6 1/2 lines from the day before that were missing GPS tags, then we continued mapping new lines in the grid, averaging about one line every 15 minutes. We paused for an hour for lunch back in camp and then worked continuously until 8:00 pm. In total, we mapped 27 lines of 3 km each, completing the grid. Then, at JP's request, we mapped a line due north from camp for a distance of 6 km, crossing the ice ridge, to test his hypothesis that snow accumulation would be higher on the north side of the ridge. That is the side facing the prevailing winds, which should advect moisture (that is, move it horizontally) off the Arctic Ocean and sea ice, and, in rising 2000 ft to pass over the dome, the saturated air would be expected to precipitate preferentially on the windward side.
Although difficult to see in snow with the glare from a full sun, the radar display can just be made out. On the left are two graphs of signal return strength versus approximate depth. On the right are various indicators of system status and a listing of the files that are being written.
In all, we covered more than 100 km (63 miles) today. Successfully completing the last lines of the grid gave us an enormous sense of accomplishment as well as relief that we were able to complete the task even in the face of adversity from weather and equipment.
Detail of the ice core drill head and cutters. The drill head and cutter are at the end of a stem, which is housed inside an outer sheath. At depth, a drilling fluid circulates between the stem and outer sheath.
At lunch we learned the drilling crew had determined that it was too warm to process ice during the heat of the day and decided to put off working on the core in the drill dome until evening. We also learned that the Twin Otter flight would require we travel light. Each of us would be limited to 40 lb of personal luggage. The rest would have to remain behind and be shipped back later.
Close up of an ice core segment, showing mostly ice, some unconsolidated firn and bubbles.
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