INNOVATION November-December 2015

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the drainage system influences ice sheet dynamics, we can learn more about how glaciers will likely respond to climate change.” During the spring thaw, meltwater fills an enormous chamber in the Kaskawulsh Glacier. An ice wall dams the chamber until summer’s rising warmth and pressure break it. Such outburst floods, commonly known by the Icelandic word jökulhlaup , can be hazardous to any infrastructure or people downstream. Flowers has used roving ice-penetrating radar developed by Laurent Mingo, P.Eng., at Blue System Integration since 2008. This year, she planned to map the dam and record a time-series that documents hydrological change where the drainage tunnel was estimated to run. Such an investigation required a fixed- point sensor to record for days—perhaps weeks. That is, she needed a fully automated system. Building a remote, stationary, automated ice-penetrating radar presented challenges for Mingo. The valley’s 80km/hr wind gusts could disturb radar antennas’ positions and solar panel orientation, and the system had to be anchored such that it followed the daily surface melt downward as the ice receded. To secure all parts and their respective orientations, the team used a set of poles drilled into the ice, fitted with long PVC sleeves. Anchoring the radar system to the sleeves allowed it to inch down the immobile poles as the glacier surface melted. This kept the system in continual contact with the ice surface. Mingo also modified the roving radar software to operate as stationary radar, and redesigned the radar transmitter to operate at low- power consumption when in sleep mode. For six weeks, and until retrieval, the system awoke every four hours, sent a few hundred radar pings over a few hundred milliseconds, recorded and formatted the data, then shut down—all within five minutes. Flowers’ team recovered the system in September 2014 and found that internal reflection through the ice plummeted. The water chambers within had emptied three days after they left. In future research, Flowers would like to install stationary radar around the ice dam, ideally year-round, to measure it filling and draining. Ice Islands The stationary radar’s success caught the attention of Carleton University researcher Derek Mueller and his doctoral student Anna Crawford. They study ice islands—relatively thin, tabletop-like icebergs hundreds or thousands of metres across. The islands calve from ice shelves and drift past Ellesmere and Devon islands, into Baffin Bay and down the Labrador coast. “Knowing how ice islands and icebergs deteriorate offers valuable information to the transport industry,” says Mueller. Modeling their degradation “helps set the limit of all known ice, a crucial point for ship traffic off Newfoundland, because insurance rates drop once a ship is clear of that limit.” Typical icebergs are notoriously dangerous to work on because they may roll anytime, but ice islands don’t roll as readily. Both kinds of formations pose threats to ships and structures, and both are ephemeral. For these reasons, the scientists proposed placing a remote, stationary ice- radar device on an ice island. The device needed two-way communication capabilities and had to record and send data daily throughout the year.

A roving radar system, receiving unit and embedded processing unit (top) can be strapped to sleds, skis or vehicles. A stationary device (bottom) is attached to sleeves over poles that are anchored in glacier ice to follow surface melt as the ice recedes. Photos: Laurent Mingo, P.Eng.

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