In an extensive airborne survey, a NASA-led team has analyzed a previously identified “hot spot” of methane emissions in the Four Corners region of the United States, quantifying both its overall magnitude and the magnitudes of its sources. The study finds that just 10 percent of the individual methane sources are contributing half of the emissions.
Scientists from NASA’s Jet Propulsion Laboratory and Caltech, both in Pasadena, California; the National Oceanic and Atmospheric Administration (NOAA), Boulder, Colorado; and the University of Michigan, Ann Arbor, used two JPL airborne spectrometers to identify and measure more than 250 individual sources of methane. The sources emitted the gas at rates ranging from a few pounds to 11,000 pounds (5,000 kilograms) per hour. Results are published this week in the Proceedings of the National Academy of Sciences in a paper titled “Airborne methane remote measurements reveal heavy-tail flux distribution in Four Corners region.” Christian Frankenberg of JPL and Caltech is the lead author.
The experiment was a proof of concept for airborne detection of methane, according to Frankenberg. “That we could observe this distribution in a widespread geographical area and collect enough plumes to perform a statistical analysis was a pleasant surprise,” he said.