As I hope to describe in more detail later this week, methane measurements in the atmosphere are consistent with the picture I just outlined. (green.blogs.nytimes.com)
They used a satellite instrument — the European Space Agency's SCIAMACHY — to get regional methane measurements over the entire United States. (sciencedaily.com)
Continuous methane measurements from a late Holocene Greenland ice core: Atmospheric and in - situ signals. (usap-dc.org)