COMPOSITION AND STRUCTURE OF THE
ATMOSPHERE.
1.1.
The composition of the atmosphere.
The atmosphere is the fluid outer layer that surrounds the Earth. It is made up of
air and airborne particles. The most abundant gases in the atmosphere are
nitrogen and oxygen. There is also carbon dioxide, water vapour and other gases,
such as argon and ozone.
Atmospheric pollution
Atmospheric pollution is the presence of substances in the atmosphere in such
quantities that they may produce discomfort or a health risk for people or other
living things.
To reduce the negative effects of pollution substances we must use less fossil fuels
and more renewable energy.
1.2.
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The structure of the atmosphere.
Troposphere: About 12 km thick. It contains 80% of the air in the atmosphere.
Wind, clouds and rain form in this layer.
Stratosphere: From 12 km up to 50 km. The ozone layer is found in the middle
of the stratosphere. It absorbs the ultraviolet radiation of the sun and gets hot.
Mesosphere: From 50km up to 80 km in height.
Termosphere: This is also called the ionosphere; it contains few gases but they
absorb extremely harmful solar radiation.
The weather and the climate
Atmospheric weather is the state of the atmosphere at a certain time and at a certain
place.
The weather is described in terms of sun, rain, clouds, frost, wind, etc.
Meteorological photo
The climate is a set of meteorological phenomena which characterise a certain region
for long period of time.
It is defined by stablishing the average of both temperature and precipitations
throughout the year or over several years.
Meteorological instruments are used to measure atmospheric phenomena. You
can see the most important ones in photos.
Barometer
Thermometer Anemometer
Pluviometer
Hygrometer
Weather vane
Activities
1. Complete the chart with the names of the atmospheric layer and the
most important phenomena that occur in them:
2. In which layer of the atmosphere do meteorological phenomena such
as rain and clouds occur?
3. Copy and complete the sentence:
Atmospheric air is made up of 78% of ……. and 21% of ……. and
other gases such as ……and……
4.Complete the sentences with the next words chosing the appropriate one
in for each case: temperature, humidity, wind, direction, rainfall and
preassure.
 A thermometer measures ………..
 A barometer measures ……….
 A hygrometer measures atmospheric …….
 A pluviometer measures the amount of …….. per square
metre.
 A weather vane shows the …….. the wind is coming from.
 An anemometer measures …… speed.