Sea Ice Survey and Generating Topological Maps
Before the spring season of marine mammal hunting, or whaling, can even start up on the North Slope, crews and other community members chip away at the sea ice to make miles-long trails to reach open water. These sea-ice pathways allow them to reach the shore and enable their long-standing cultural practice of marine mammal hunting. The process is done with hand tools — mostly ice picks — taking days or weeks, and is very labor intensive. So when researchers at the University of Alaska Fairbanks offered to fly a small, unmanned aircraft over the ice in hopes of finding the safest, most efficient routes to open leads, whaling captains in Barrow were enthusiastic. In April 2015, a Ptarmigan unmanned aircraft was launched and flown in a grid pattern 400 feet over a section of ice about 2,600 feet by 600 feet.
After the flights, a technique called structure-from-motion was used to create an accurate three-dimensional map of the surface. This technique had not been extensively used for ice modeling, and the use of this technique on ice was pioneered by researchers at UAF’s Geophysical Institute. The result was a topographic map that allowed whalers to take a closer look at ice conditions and find the best routes to open leads and the whales that show up there. The aircraft was not used to locate whales, only to enable the whaling community and ensure a safe route for them.
“This technique is something that’s been pioneered here at UAF, especially in areas like ice and snow,” said Dyre Oliver Dammann, a doctoral student who, along with Eyal Saiet, a staff member for the Alaska Center for Unmanned Aircraft Systems Integration, came up with the idea to map the ice using the hexacopter.
For the 2015 spring season, these 3D maps were available to crews online and for download onto phones or other devices. “We provided what we call a digital elevation model, that shows where the large ridges are and where the smooth areas are,” Dammann said. “From that, (they) can immediately identify potential risks.” Researchers and scientists at UAF have been working in the Arctic for years studying sea ice. “Researchers should always aim to give something back to the community,” Dammann said. “We’ve been trying to understand sea ice and dynamics that are relevant for larger aspects such as climate change, but we’re also very interested in conducting research that has a direct implication for people that live there.”
Whalers, who navigate sea-ice, already know a lot about how the ice behaves during spring break up and scientists rely on local knowledge when conducting research there. “So we were trying to provide something that they can learn from that they couldn’t otherwise do,” Dammann said. “It’s a really great relationship.” UAF started mapping whaling trails in the ice about seven years ago to help captains and their crews by identifying not only safer routes, but also more efficient routes, thus saving time and money. Then we approached them about flying an unmanned aircraft over and actually get the topography of the ice ... and they said they were all for that.”