The Arctic is warming about twice as fast as the rest of the planet, but major questions remain, including how quickly sea ice will retreat, and how much of Greenland’s ice will slide into the sea, over the decades to come. A new NASA-led experiment could help deliver answers, by measuring a key component of the Arctic’s energy balance from space for the very first time.
In the early 2020s, NASA will launch the Polar Radiant Energy in the Far Infrared Experiment (PREFIRE), a pair of lightweight satellites carrying instruments capable of measuring far infrared emissions from Earth’s poles. Tristan L’Ecuyer, a climate scientist at the University of Wisconsin, Madison and principal investigator on the experiment, called the far infrared a “very important region of the energy exchange...that governs the Arctic climate.”
“This is a completely unique measurement we need,” L’Ecuyer told Earther.
Tom Wagner, NASA program scientist for the cryosphere, was similarly enthused about the experiment’s potential. “They may really start to understand what the heck is going on with energy balance in the Arctic and why it’s heating faster than the rest of the planet,” he told Earther.
A bit of basic Earth science: The temperature anywhere on our planet’s surface is governed by the balance between what comes in from the Sun, and what goes out, or is re-radiated, by Earth’s surface and atmosphere. Compared to the visible and UV light coming in, the stuff leaving the Earth is shifted to longer, lower-energy wavelengths in the infrared part of the spectrum. That’s because the temperature of the Earth itself is much lower than the temperature of the Sun.
Because the poles are, well, very cold, a lot of the energy leaving the Earth there—about 60 percent of it—is emitted at even longer wavelengths in the far infrared. And according to L’Ecuyer, while we’ve been able to measure far infrared emissions from the ground, “up until now, we’ve never had the tech to launch an instrument into space and have it function in a space environment,” which is needed to get snapshots across the entire Arctic. “It was always too expensive.”
The bread loaf-sized satellites, or CubeSats, that’ll fly the new experiment are dirt cheap compared with, say, the big new weather satellite NASA launched last month. L’Ecuyer is hopeful that once the experiment is airborne, taking round-the-clock and cross-seasonal measurements that members of the PREFIRE team will feed into climate models, we’ll be able to start making much better predictions about the Arctic’s future.
He says the work has taken on added urgency in light of this winter’s freak Arctic warming event, and the fact that the Arctic is now hitting new sea ice lows year after year. But L’Ecuyer is also just excited to be taking a completely new type of measurement.
“We know what we can learn right away,” he said. “But I think there’s also the excitement of learning things we never imagined.”