NASA technology detected millions of Arctic methane 'hotspots'

Posted Feb 16, 2020 by Karen Graham
Scientists are taking to the skies to study methane emissions in the Arctic. In a series of more than 400 airplane rides in 2017, researchers with NASA’s Arctic Boreal Vulnerability Experiment discovered 2 million methane hotspots.
The image shows a thermokarst lake in Alaska. Thermokarst lakes form in the Arctic when permafrost t...
The image shows a thermokarst lake in Alaska. Thermokarst lakes form in the Arctic when permafrost thaws.
The Arctic is one of the fastest-warming regions on Earth, and as temperatures rise, the frozen soil begins thawing, releasing methane and other greenhouse gasses into the atmosphere.
For climate scientists, it is necessary to know how much methane and other gasses are being released and to what extent - as well as what other environmental factors may influence methane's release.
Scientists with NASA's Arctic Boreal Vulnerability Experiment (ABoVE), using groundbreaking technologies, have documented the extent of methane emissions in the Arctic and published their findings on February 10, in the journal, Geophysical Research Letters.
The field mission took place in 2017. Using planes equipped with "AVIRIS-NG" infrared technology, the scientists documented methane hotspots, which the team defined as an area with 3,000 parts per million of methane in the air. In total, the scientists covered 20,000 square miles (30,000 square kilometers) of land and took roughly 1 billion observations.
The instrument did not disappoint, according to Science Daily. Lead author Clayton Elder of NASA's Jet Propulsion Laboratory in Pasadena, California said, "And we detected 2 million of these hotspots over the land that we covered."
In compiling the datasets, the scientists also discovered an interesting pattern to the hotspots. On average, the methane hotspots were mostly concentrated within about 44 yards (40 meters) of standing bodies of water, like lakes and streams.
Past the 44-yard marks, the presence of the hotspots began to drop off and at about 330 yards (300 meters) from the water source, they dropped off almost completely. The researchers weren't sure about the 44-yard "magic number," and what significance it had, but further studies conducted on the ground have provided some answers, according to Gizmodo Earther.
"After two years of ground field studies that began in 2018 at an Alaskan lake site with a methane hotspot, we found abrupt thawing of the permafrost right underneath the hotspot," said Elder.
"It's that additional contribution of permafrost carbon, carbon that's been frozen for thousands of years—that's essentially contributing food for the microbes to chew up and turn into methane as the permafrost continues to thaw."
Elder says the study is also a technological breakthrough. "AVIRIS-NG has been used in previous methane surveys, but those surveys focused on human-caused emissions in populated areas and areas with major infrastructure known to produce emissions," he said. "Our study marks the first time the instrument has been used to find hotspots where the locations of possible permafrost-related emissions are far less understood."
AVIRIS-NG is an acronym for the Airborne Visible InfraRed Imaging Spectrometer - Next Generation. AVIRIS-NG has been developed to provide continued access to high signal-to-noise ratio imaging spectroscopy measurements in the solar reflected spectral range.
AVIRIS-NG was launched in 2012 using a Twin Otter platform. AVIRIS-NG measures the wavelength range from 380 nm to 2510 nm with 5 nm sampling. Spectra are measured as images with 600 cross-track elements and spatial sampling from 0.3 m to 4.0 m.
This new knowledge will improve how Arctic land models represent methane dynamics and therefore our ability to forecast the region's impact on global climate and global climate change impacts on the Arctic.