Fairbanks Fodar is 'ideal for mapping changes': UAF scientist develops airborne measurement system.

• Author: Stricker, Julie
• Position: TECHNOLOGY

Kit DesLauriers had a problem.

The adventurer, known for being the first person to ski down the highest summits on all seven continents, wanted to ski the highest peak in the western Brooks Range, but she wasn't sure which mountain was tallest. In the 1950s USGS (United States Geological Survey) made two maps of the region with different scales. One showed Mount Isto was the tallest; the other pointed to Mount Chamberlin. The difference was about fifty feet.

Puzzle Solving

While waiting for a flight in Coldfoot, DesLauriers bumped into Matt Nolan, a UAF (University of Alaska Fairbanks) scientist who has been studying the Brooks Range glaciers since 2003. She told him about the USGS discrepancy and they hatched a plan to solve the puzzle.

Nolan is a camera buff who has experimented with various types of large-format photography and other methods to measure the volume of McCall Glacier over time. The year before DesLauriers brought the IstoChamberlin discrepancy to his attention, he had started developing an airborne measurement system. Solving the peak problem would be a good test of the efficiency and accuracy of his system, and it would add to the scientific knowledge of the Brooks Range.

DesLauriers climbed both mountains with a GPS receiver to serve as a ground measurement. Then Nolan climbed into his small airplane and flew over the mountains, taking pictures with a Nikon camera mounted on the bottom of the plane, which is also hooked up to a professional-grade GPS. When he returned to the ground, he compared his readings to those taken by DesLauriers. They matched to within a few centimeters, showing Mount Isto is the highest peak in Alaska's Arctic at 8,975 feet.

Innovative Remote-Sensing

To measure the peaks, Nolan used an innovative remote-sensing program he calls fodar, a compound of "foto" and "lidar." (It's not an acronym and it's not capitalized, he says.) Nolan created it as a way to inexpensively and accurately map such things as snow depth, glacial volume, erosion, and infrastructure. He uses the system to create topographic maps that he can then layer and compare to note changes in the landscape as small as five to fifteen centimeters.

It's similar to Lidar, which uses lasers to measure distance, he says, but it's much less expensive and the results are equally accurate. And, it generates actual photos of the area being mapped, which are also useful for comparisons.

Here's how it works: Nolan mounts a professional-grade...