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CNSC Log Day 2 Sunday 5th October 2008
6.30am start again with Breakfast at 7am sharp. This is not a holiday!
Briefing at 7.45am in the large unheated laboratory. Here we were introduced to the GPR (Ground Penetrating Radar). We all knew we would grow to love this instrument over the next 11 days. We spent about an hour in a detailed lecture on the systematic setup and operation of this very valuable research tool. 3 minutes to get ready again for a survey of the Tundra site, a long drive over very rough potholed roads. We saw a mother bear and her cub on our drive, which was good as we could all tick this one off our list now. We set up two 50m tapes perpendicular to each other and sampled the permafrost underground every 25cm. The instrument comprises all plastic construction with a transmitter mounted on a heavy plastic ski approximately 1m long with tall plastic handles for holding the instrument in position. This is powered by two 6 volt motor bike size batteries. The detector is identical in construction and is operated with a separation of exactly 1m with both tracks held parallel. The transmitter and detector are connected together by optical fibre, which is then connected to a signal processor which must be kept more than 5m away from the measuring instruments to reduce electrical "noise". The processor is powered by a 12 volt bike battery and is connected to a HP Palm to store the data. Operators with steel toed boots are excused from taking their turn in operating the GPR. The unit sends a pulse of radar at 100MHz to a maximum depth of 15m. Every 25cm the heavy unit is lifted and moved for a new reading which is recorded on a second data logger. When the readings are taken near to a source of steel such as a leg of an environmental monitoring station or other steel pegs that can not be removed this must be manually noted in the data logger. A slow tedious process but one that provides invaluable data that can be periodically compared.
While we proceeded with the GPR Peter downloaded data from a nearby monitoring station that looked somewhat battered. It had recently been knocked over by a Polar Bear and one of the 5 instruments still had not been replaced. One detector measured solar radiation by an array of black and white thermocouples mounted on a metal disc and exposed to sunlight. Another measured snow depth by pulsing a sonic signal to the ground every 5 seconds and measured the reflection. There were two anemometers one at 1.5m the other should have been at 2m but had been destroyed by the PB attack. Temperature thermocouple probes were at 1.5m, 0m ,-20cm, -40cm and -80cm. Data from all sensors was stored in a black box in a black box with a bag of desiccant inside. Batteries inside the equipment were trickle charged by a solar panel. Quite a sophisticated looking set up, particularly the two large rocks placed on top to prevent it blowing away during the fierce polar winds.
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