At any given moment about 4000 commercial aircraft are flying over the Earth. To an atmospheric scientist they constitute a potentially vast array of in situ measurement platforms, an obvious source of high-resolution upper tropospheric/lower stratospheric (UT/LS) trace gas data that could not be obtained on such a continuous basis in any other way, especially over the oceans.
The number of flights has been steadily growing, and the long-term outlook for continued “funding” looks excellent given the penchant for humans to travel around the world. And yet, to date, there have been few attempts to tap this resource for atmospheric chemistry studies. One study, however, has chalked up 40 million miles over the past 5 years.