Example
Remote sensors can observe enhancements above background conditions and estimate release rates.
The catch
Wind, cloud cover and measurement sensitivity influence interpretation.
Related terms
Methane, Anthropogenic methane, Biogenic methane, Flaring, Fossil methane, Fugitive emissions
In more depth
Methane plume, explained.
A methane plume turns an invisible leak into evidence that can be located and sized. Analysts estimate the release rate by combining how much extra methane the plume holds with the wind speed carrying it away. Satellites range from broad mappers that see regional excesses to fine-resolution instruments that can pin a plume to a single facility, while aircraft and drones fill in detail.
A plume is a snapshot. Many large releases are intermittent, so a single sighting cannot give an annual total. Attribution needs care where facilities sit close together. UNEP runs a system that alerts governments and operators to large plumes detected from space, which turns detection into a request for repair. Report the measurement uncertainty alongside any rate, and treat repeated sightings at the same super-emitter as a sign of a management problem.