Download Our Atmosphere

The atmosphere The atmosphere is the air that surrounds the Earth. It extends upwards
for hundreds of kilometres until it reaches space. Earth's atmosphere
acts as a blanket. It is able to absorb heat as well as reflect some of the
Sun's rays. This keeps the Earth's surface from getting too hot or too
cold.
If Earth did not have an atmosphere then it would look like the moon. The
moon has no atmosphere and because of this is not protected from the
extreme temperatures of space. On the moon the days are extremely hot,
whilst the nights are freezing cold. As there is no atmosphere there is
also no moisture, or water vapour, therefore no rain, snow or hail. No
living thing can survive on the moon because there is no oxygen.
The atmosphere is divided into five distinct layers that are:
• the troposphere
• the stratosphere
• the mesosphere
• the thermosphere
• the exosphere.
The atmosphere becomes thinner the further up you travel until it
merges with space.
All weather occurs in the troposphere, which is the layer of the
atmosphere closest to the Earth's surface.
It is very unstable in the troposphere layer of the atmosphere which is
why aeroplanesfly at the top of this layer. If areoplanes flew in the
trophosphere layer they would experience a lot of turbulence.
Chapter 2: The Earth’s atmosphere The atmosphere is the air that surrounds the earth. Is made up of 4
layers:
The Troposphere:
Almost all weather and related processes take place here in the
troposphere. The troposphere extends up to 17 kilometres above the
Equator. Between the troposphere and the next layer, the
stratosphere is the tropopause where temperatures are very low:
about -40 celcius to -80 celcius. The air here is so cold that
clouds are made up of ice crystals. The air within the troposphere is
warmed by the heat that is radiated from the earth’s surface. We live
in this layer
The Stratosphere:
The stratosphere extends about 50 kilometres above the earth’s
surface. In the lower part of the stratosphere, temperatures are
relatively constant and stable. However in the upper stratosphere
temperatures increase up to 0 celcius at the top of the stratosphere
due to the absorption of solar radiation. This section at the top of the
stratosphere is known as the stratopause. It contains most of the
atmosphere’s ozone. The ozone heats the air there by absorbing ultra
violet rays from the sun.
The Mesosphere:
The mesosphere extends about 80 kilometres above the earth’s
surface. Temperatures fall rapidly with elevation because there is no
water vapour, cloud or dust to absorb incoming radiation. The lowest
temperatures in the earth’s atmosphere occur at the top of the
mesosphere called the mesopause. Temperatures get as low as -90
degrees celcius and wind speeds are as high as 3000 kilometres per
hour, the strongest in the atmosphere.
The Thermosphere:
The thermosphere is the uppermost temperature region of Earth's
atmosphere. The thermosphere is completely exposed to the sun’s
radiation. The sun heats the extremely thin air to exceptionally high
temperatures such as 1500 degrees celcius.