Stratosphere: 12 to 50 km (7 to 31 miles):
- The stratosphere is the second-lowest layer of Earth's atmosphere. It lies above the troposphere and is separated from it by the tropopause.
- It contains the ozone layer.
- The stratosphere defines a layer in which temperatures rise with increasing altitude. This rise in temperature is caused by the absorption of ultraviolet radiation (UV) radiation from the Sun by the ozone layer, which restricts turbulence and mixing. Although the temperature may be −60 °C at the tropopause, the top of the stratosphere is much warmer, and may be near 0 °C.
- The stratosphere is almost completely free of clouds and other forms of weather.
- This is the highest layer that can be accessed by jet-powered aircraft.
- Bacterial life survives in the stratosphere and some bird species have been reported to fly at the lower levels of the stratosphere.