By now, the ground-penetrating radar (GPR) team has probably begun inching along the first 60 miles of the GrIT traverse route, scouting safe passage for the tractors and sleds that will embark in mid-April for Summit Station. GrIT mechanic / equipment operator (/photographer) Robin Davies sent photos explaining how the team finds and marks hidden hazards in the tumbly ice that is the transition from land to ice sheet proper. Ride along.
The ground-penetrating radar (GPR) is seen through the windshield of the Tucker. The instrument uses electromagnetic waves to detect structural changes not obvious from the surface of the ice—crevasses, notably. All photos: Robin Davies
Inside the Tucker: Jennifer Mercer, Allan Delaney (rear) and Robin Davies. Delaney monitors the output from the radar constantly.
Mercer checks satellite images as Delaney monitors the radar output. Experts like Mercer can detect surface disturbances on satellite images, but sometimes a seemingly smooth surface masks hidden crevasses. That's where the GPR really proves its worth.
When Delaney sees a potential crevasse in the radar output, Davies stops the Tucker. Mountaineer/medic Kevin Emery, riding behind the Tucker on a snowmachine, comes forward to inspect the area of interest. Here, Emery profiles the suspected crevasse while lashed to his snowmachine.
After digging through the snow bridge covering the crevasse, Emery determines the fissure is a bit over two feet wide. That's too wide for safe crossing, so Emery marks the spot with black flags and the Tucker prepares to back up and find a safe route. The GPR team will likely engage in these activities scores of times on this advance-scouting traverse, but clearly risk mitigation makes the effort worthwhile.
The Greenland Inland Traverse, a collaboration between the National Science Foundation (NSF), CH2M HILL Polar Services, and Cold Regions Research and Engineering Laboratories, is funded by the NSF’s Office of Polar Programs. The 2010 spring traverse has several foci: find a safe route to Summit Station that may reduce logistical and other impacts of conducting research there; provide a research platform for scientists conducting field work in Greenland; optimize mobility by focusing on the sled/snow interface. For more on GrIT, click here.