Vanguard Magazine

a arcTic 26 DECEMBER 2015/JANUARY 2016 www.vanguardcanada.com Back in the lab, when they reviewed the images they took, the researchers discovered that the snow had registered what Leblanc described as "nice big linear anomalies in the data." Subsequent investigations revealed the "anomalies," which appeared as red lines, were actually tracks in the snow. This was when it dawned on them they were onto something. The infrared lines could hold the clue as to whether tracks have been in the snow for several days or if they are a more recent disturbance. Studying snow disturbance is nothing new and has in fact been around for cen- turies if not thousands of years. If search- ers can view tracks from the air they could cover a bigger area in a shorter period of time. However, detecting tracks from the air is difficult since various factors such as weather, angle of view and type of snow come into play. "While most applications of disturbed snow have focused primarily on the is- sue of disturbed vs. non-disturbed snow, in our work we have focused on the sub- ject of qualitatively identifying recently vs. non-recently disturbed snow within the range of the shortwave infrared (SWIR)," said Leblanc. Spectral imaging has the potential to shorten the time it takes for searchers to determine which tracks to investigate. "There are several advantages that this approach has, namely, when there is a time- critical component (such as in SAR activi- ties) where we would be looking to identify recently disturbed snow as opposed to snow that had been disturbed at some time well- prior to the search," said Leblanc. The method can also be used in conjunc- tion with current drone technology so that searches can be conducted remotely em- ploying unmanned autonomous vehicles (AUVs). Developing operational application The NRC team is now gearing up to ex- pand their research. The winter has been mild so far, but hopefully, January will bring in more snow. By then the team expects to launch both manned and unmanned aircraft over the fields around Ottawa. They will be look- ing for further indicators that this new method of observing disturbed snow has practical operational potentials. The key to this is being able to estab- lish metrics that can be used to judge the time differences around snow disturbance as well as changes in the snow caused by different types of disturbances. By establishing these parameters, the re- searchers hope to be able to determine the difference between tracks that have been left from several days ago from those that were made about an hour ago. The characteristics of snow also change depending on the size, weight and type of object moving it. For example, when people walk over snow we tend to trans- form the snow grains from something that is "snow-like" to something more "ice-like." The different grain sizes of snow reflect different wavelengths of light which the hyperspectral imager can detect. "Our ultimate goal is to develop this up to the point that it is operational," said Leblanc. infrared anomalies could hold the clue as to whether tracks have been in the snow for several days or if they are a more recent disturbance. Measurement of a standard calibration target by a ground-based spectrometer during snow- related activities. This measures the amount of change in the snow signal due to the motion of the sun and other external factors.

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