Using fodar, a technique he invented to map terrain using airborne photography, glaciologist Matt Nolan created a high-resolution topographic map of the Brooks Range in Alaska, which reveals Mount Isto to be the tallest mountain in the US Arctic, standing 8,975 feet tall.
|A map of the five tallest peaks in the Alaskan arctic, measured by fodar (Image: Nolan & DesLauriers, The Cryosphere, 2016)|
The results of their survey, along with details of the technique, were published in The Cryosphere. Although the method is new, it has roots in an old technique called photogrammetry, where researchers use scale photographs to make cartographic measurements. The difference is in how it’s applied.
Both Mount Chamberlin and Mount Isto claimed the title as their own. Now, one has emerged triumphant—and a third, entirely separate mountain peak has also entered the race. Mount Isto is 2735.6 meters and Mount Chamberlin is a full 23 meters shorter at 2712.3 meters—but that doesn’t push Mount Chamberlin to the number two spot. Instead, a third, unsuspected peak from further away, Mount Hubley emerged in the survey with a height of 2717 meters to yank the title and push Chamberlin to number three.
|Kit DesLauriers on the Isto climb (Image: Andy Bardon via University of Alaska Fairbanks)|
That’s when Nolan decided to put his technology to the test to find out. As he flew over the Brooks Range in a Cessna 170B equipped with a DSLR camera linked to a GPS unit, skier and mountaineer Kit DesLauriers climbed up and skied down the mountains with her own GPS unit, allowing the pair to chart elevations from the air and ground simultaneously to provide a “measure of accuracy.” The resulting maps are accurate to about 8 inches.
Nolan notes his technology is much like lidar but costs $30,000 rather than $500,000 and can measure coastal erosion, glacier melt, and landslides. “The possibilities are truly unlimited,” he says.
|Mount Isto, with every on-the-ground GPS measurement shown in yellow (Image: Nolan & DesLauriers, The Cryosphere, 2016)|
Nolan also explained that the technique could be used to track changes not only in glaciers but also in permafrost, coastlines, rivers, and even the break-up of the ice sheets. With the technique, we can get an even more complete, real-time map of the ways our planet is changing as it warms.