The highly stratified region of the atmosphere above the troposphere extending
from about 10 km (ranging from 9 km in high latitudes to 16 km in the tropics on
average) to about 50 km.
Among other gazes, the stratosphere contains small amounts of gaseous ozone
(O3), which filters out about 99 percent of the incoming harmful ultraviolet
(UV) radiation. Most commercial airline flights operate at a cruising altitude
in the lower stratosphere.
