The stratosphere is the second layer of Earth's atmosphere, just above the troposphere. It extends from about 10 kilometers (6 miles) to 50 kilometers (31 miles) above Earth's surface. The stratosphere is mostly dry, with very little weather. The temperature increases with height in the stratosphere, reaching a maximum at the stratopause. The stratosphere is important because it contains the ozone layer, which protects life on Earth from the Sun's ultraviolet radiation.
It lies above the troposphere and below the mesosphere. The stratosphere is stratified in temperature, with warmer layers higher up and cooler layers lower down. This is in contrast to the troposphere, which is well mixed. The stratosphere is mostly free of clouds and other forms of precipitation.
The stratosphere was discovered in the early 19th century by balloonists who noticed that the temperature increased with altitude. In the 1920s, the British meteorologist L.F. Richardson showed that the stratosphere is stratified.
The stratosphere is important because it contains the ozone layer, which absorbs ultraviolet radiation from the Sun. This radiation is harmful to living things, and so the ozone layer protects us from it.
The stratosphere is also home to the jet stream, which is a fast flowing river of air that helps to drive the weather.
