GeoMag

T H E L AY E R S O F T H E AT M O S P H E R E

SAMUEL HARWOOD

THE LAYERS OF THE ATMOSPHERE

Northern Lights Manas Mapara

The Layers of the Atmosphere Troposphere

Exosphere The exosphere is located between 700 and 10,000 kilometres above the Earth’s surface, and it is the highest layer in the Earth’s atmosphere. At the top of the exosphere layer, it merges with solar wind. Any molecules found here have extremely low density, meaning that this layer does not behave like a gas, and particles here escape into space. Even though there is no weather in this layer, the aurora borealis and aurora australis are sometimes seen in the lowest part. Most satellites orbit in the exosphere.

The troposphere is the first layer of the atmosphere. It goes up to 12 kilometres high and contains around 99% of all the water vapour and aerosols. It is probably the most important layer, as it is where we all live. Most of the weather happens in this layer, apart from the cumulonimbus thunder clouds, whose tops can rise to the bottom of the Stratosphere. Stratosphere This is probably the most well-known layer and is found from 12-50 kilometres off the ground. It is home to the ozone layer, which is extremely important, as it protects us from the Sun’s harmful ultraviolet radiation. This means that the stratosphere and the troposphere are protected from the Sun’s rays whereas the other layers aren’t. It is nearly free from clouds and weather, apart from polar stratospheric clouds, which are sometimes there in its lowest, coldest altitudes. Mesosphere The mesosphere is located from 50 to 80 kilometres above ground, and gets increasingly colder with altitude. The top of the mesosphere layer is the coldest place found within the Earth system, with an average temperature of -85 degrees Celsius. Because of the scarce amount of water vapour at the top of the mesosphere layer, noctilucent clouds are formed, which are the highest clouds in the Earth’s atmosphere, which can be seen by the naked eye under certain conditions and at certain times of the day. This layer is where most meteors burn up, and sounding rockets and rocket powered aircraft can reach this layer. Thermosphere The thermosphere layer is positioned between 80 to 700 kilometres in the air. The lowest part of the thermosphere is where the ionosphere is found. In the thermosphere, the temperature increases with altitude because of the very low density of the molecules found here. It is cloud and water vapour free. The aurora borealis and aurora australis are usually found here. The International Space Station orbits in the thermosphere.

Udaipur Kishan Popat

Sunset Jenson Ives

Sunset Beams Anay Desai

20 | Geographical Magazine • Merchant Taylors’ School

2021/22 Edition | 21