This spectral "fingerprint" of methane was produced from data taken during a September 2023 test at NASA's Jet Propulsion Laboratory in Southern California of a state-of-the-art imaging spectrometer that will measure the greenhouse gases methane and carbon dioxide from space.

The instrument measures hundreds of wavelengths of light reflected by Earth's surface and absorbed by gases in the planet's atmosphere. Different compounds absorb different wavelengths of light, leaving a kind of spectral fingerprint that the imaging spectrometer can identify. These infrared fingerprints, invisible to the human eye, can pinpoint and quantify strong greenhouse gas emissions, and accelerate mitigation efforts.

Before the imaging spectrometer was shipped from JPL to Planet Labs PBC in San Francisco, where it will be integrated into a Tanager satellite, there was a rare opportunity to use a sample of methane to test the completed instrument while it was in a vacuum chamber. The test was successful, and the imaging spectrometer produced this clear spectral fingerprint of methane (appearing as a red line in the graph).

Designed and built by JPL, imaging spectrometer will be part of an effort led by the nonprofit Carbon Mapper organization to collect data on greenhouse gas point-source emissions. The information will help locate and quantify "super-emitters" – the small percentage of individual sources responsible for a significant fraction of methane and carbon dioxide emissions around the world.