NASA mission excels in detecting sources of greenhouse gas emissions

Since its launch 16 months ago, the EMIT imaging spectrometer aboard the International Space Station has demonstrated the ability to detect more than just surface minerals.

More than a year after first detecting methane plumes from its perch aboard the International Space Station, data from NASA’s EMIT instrument is now being used to identify point-source emissions of greenhouse gases. greenhouse with a proficiency that surprised even its designers.

Short for Earth Surface Mineral Dust Source Investigation, EMIT was launched in July 2022 to map 10 important surface minerals in the world’s arid regions. These mineral-related observations, which are now available to researchers and the public, will help improve understanding of how dust released into the atmosphere affects climate.

Methane detection was not part of EMIT’s primary mission, but the instrument’s designers hoped the imaging spectrometer would have this capability. Now, with more than 750 sources of emissions identified since August 2022 – some small, others in remote locations and others persistent over time – the instrument has more than produced results in this regard, according to a new study published in Science Advances.

“Initially, we were a little cautious about what we could do with the instrument,” said Andrew Thorpe, a research technologist on the EMIT science team at NASA’s Jet Propulsion Laboratory in Southern California and lead author of the paper. “It exceeded our expectations.”

By knowing where methane emissions are coming from, operators of landfills, agricultural sites, oil and gas facilities, and other methane producers have the opportunity to address these issues. Tracking human-caused methane emissions is critical to limiting climate change because it offers a quick and comparatively low-cost approach to reducing greenhouse gases. Methane remains in the atmosphere for about a decade, but during this time it is up to 80 times more powerful at trapping heat than carbon dioxide, which remains for centuries.

Surprising results

EMIT has proven effective in detecting emission sources both large (tens of thousands of pounds of methane per hour) and surprisingly small (up to hundreds of pounds of methane per hour). This is important because it allows the identification of a greater number of “super emitters” – sources that produce disproportionate shares of total emissions.

The new study documents how EMIT, based on the first 30 days of greenhouse gas detection, can observe 60% to 85% of the methane plumes typically observed in aerial campaigns.

At several thousand feet above the ground, methane-detecting instruments on aircraft are more sensitive, but to warrant sending a plane, investigators need an advance indication that they will detect methane. Many areas are not examined because they are considered too remote, too risky or too expensive. Furthermore, the campaigns that take place cover relatively limited areas for short periods.

On the other hand, at around 400 kilometers above sea level on the space station, EMIT collects data on a large part of the planet – specifically the arid regions that lie between 51.6 degrees north and south latitude. The imaging spectrometer captures 80-by-80-kilometer (50-mile-by-50-mile) images of the surface — researchers call them “scenes” — including many regions that have been out of reach of airborne instruments.

“The number and scale of methane plumes measured by EMIT around our planet are impressive,” said Robert O. Green, JPL senior scientist and EMIT principal investigator.

Scene-by-scene detections

To support source identification, the EMIT science team creates maps of methane plumes and posts them on a website, with underlying data available from the United States Geological Survey Earth Processes Distributed Active Archive Center (LP DAAC). Mission data is available for use by the public, scientists and organizations.

Since EMIT began collecting observations in August 2022, it has documented more than 50,000 scenes. The instrument detected a cluster of emissions sources in a rarely studied region of southern Uzbekistan on September 1, 2022, detecting 12 methane plumes totaling about 49,734 pounds (22,559 kilograms) per hour.

Furthermore, the instrument detected much smaller plumes than expected. Captured in a remote corner of southeastern Libya on September 3, 2022, one of the smallest sources so far emitted 979 pounds (444 kilograms) per hour, based on estimates of local wind speeds.