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Canadian technology marks future of snow studies

Researchers studying how sound waves travel through snow to produce snow property profiles



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While FMCW microwave radar (frequency modulated continuous wave, used by police speed-traps) measures snow depth or snow density (but not both) without touching the snowpack, the SAS2 is the first device to determine depth, density, temperature and wetness successfully from one measurement without contact.

"Nobody has been able to do that," Kinar said. "As soon as the shovel comes in contact with the snow, you modify the properties. Using sonar — it's like making a fingerprint without touching the skin on to paper."

Kinar is developing the device as a PhD project with the University of Saskatchewan's Centre for Hydrology. His supervisor, Dr. John Pomeroy, Canada research chair in water resources and climate change, said he recognized quickly that Kinar, 30-ish, is exceptionally intelligent. He approached Kinar about working on novel instrumentation for snow.

After testing several prototypes, Kinar spent many months designing and building the SAS2. The circuit board, consisting of eight ultra-thin layers with the smallest distance between layers being five mil (1 mil equals 1,000th/inch), was manufactured by a specialized facility. Kinar mapped the 120,000 traces, or connections, one by one on a computer. He used a special soldering iron with a tip smaller than one millimetre to attach dozens of surface mount components — ultra-tiny technology used in iPods and cell phones.

"It's been much more difficult than I ever anticipated," Kinar admitted. "It's both a fine art and a science. It certainly gives you more satisfaction when you buy electronics in the store!"

Kinar experimented with many sources to find a lithium battery that could last 12 hours, and function in temperatures as low as minus 40. Employing top-tier FMCW radar, the SAS2 operates at a sampling rate of 2.1 Mhz/second (2.1 million times per second). Results are analyzed in a custom computer program and graphed as an image of the snow cross-section.

"The speaker and microphones are standard stuff," Pomeroy said. "What is special is the computer board, which is more complex than a laptop computer and was custom designed and partly hand built by Nicholas — incredible."

Thus far Kinar has published papers on the earlier prototypes and will soon publish on the SAS2. His presentation at the 2011 American Geophysical Union meeting in San Francisco earned him the organization's prestigious Horton Award. He will present in Banff in June at the 2012 Canadian Geophysical Union Conference.

While the U.S. military employs similar technology for seismic and geological purposes, no-one has yet developed functioning technology to read snow. Current methods include the Swiss-designed snow microbe penetrometer, a digital probe that can send signals to read snowpack properties.

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