The information on this site is subject to a disclaimer and a copyright notice . The aircraft have found surprisingly low temperatures at the boundary between the lower atmosphere and the stratosphere. At this boundary, called the tropopause, the aircraft detected some of the thinnest clouds on Earth, which, although thin, play nevertheless a critical role in climate change. Moreover, because nearly all of the air entering the stratosphere does so in the tropics, tropical atmospheric processes have an impact on stratospheric ozone at global scale.
Clouds affect climate by trapping heat emitted from the Earth and by reflecting sunlight.
The size of these two effects on climate is uncertain for all cloud types, but most uncertain for high clouds in the tropics because detailed measurements are missing. The Intergovernmental Panel on Climate Change, the forum set up to provide the scientific advice on climate change to governments, recently identified the lack of knowledge about high tropical clouds as one of the largest obstacles in the way of a definitive statement on how climate is changing. The second aircraft, a Russian M-55 Geophysica operated by Myasischev Design Bureau, which flies at about twice the height of commercial airliners, made measurements inside the clouds. The equipment on the Falcon can provide rapid information on cloud position, and this was relayed to the Geophysica. This allowed the two aircraft to make combined measurements in very thin layers of cirrus clouds, which are visible to the laser equipment but not to the human eye, or to satellites.