THE ATMOSPHERE AND ITS CHANGES.

Functions and composition of the atmposphere.

Atmosphere: gaseous layer that surrounds the Earth.

Composition: is made up of water vapour and a mixture of gases:

• nitrogen, 78%
• oxygen, 21%
• ozone.
• carbon dioxide.

Its makes life on Earth possible because:

• it provides gases that are essentials to life (oxygen).
• it filters dangerous solar radiation
• it regulates the planet's temperature.
• it protects the planet from the impact of meteorites.

In 1908 a meteorite was disintegrated by the Earth's atmosphere over Siberia. The explosion flattened 2.000 square kilometres of trees.

The atmosphere's layers.

We can divide the atmosphere into five layers with different characteristics:

1. Exosphere between 500 and 10.000 kilometres.Highest layer of the atmosphere. Its density is very low.
2. Ionosphere, between 500 and 80 kilometres. Its high temperature (1500 deegres) causes meteorites to disintegrate.
3. Mesosphere, between 80 and 50 kilometres. The coolest layer of the atmosphere (-90 deegres).
4. Stratosphere, between 50 and 12 kilometres. It is contains the ozone layer that protects Earth from ultraviolet rays
5. Troposphere, between 12 kilometres and Earth's surface. Its produces the planet's meteorological and climatic phenomena.

Northern Lights.

Atmospheric phenomena. Weather and climate.

We have to distinguis between the atmospheric weather an the climate.

• Atmospheric weather is the state of the atmosphere over one place at a specific time. The weather is changeable and can be different every day. This is because the troposphere is divide into large air masses that are moving continuously over the Earth's surface.

The science that study the weather is meteorology.

Heatwave in London.

Snowfall in Jerusalem.

• The climate is the average state of the atmosphere over one place during a long period ot time. It is calculated observing the succession of types of weather for at least thirty years. Is more stable than weather.

The science that study the various types of climate is climatology.

ACTIVITIES:

You can find the solutions here.

1. Indicate which of these phrases refers to weather and which to climate.
a). The summers in Madrid are very hot and almost without precipitations.
b). The evening was cloudy and windy in London yesterday.
c). Weather is always hot and rainy in Indonesia.
d). This June has been hotter than usual in Seville.
e). They said that winters are very cold in Bergen.
f). Last week was raining all the time in Barcelone.

2. Match the definitions with the righ Word:

a). The layer in which take place the weather phenomena. b). The hottest layer of the atmosphere. c). The coldest layer of the atmosphere. d). The last layer of the atmosphere, located at an altitude of between 500 and 10.000 kilometres. e). The layer in which the ozone layer is located.

1.         Exosphere. 2.        Mesosphere. 3.         Ionosphere. 4.     Trosposphere. 5.         Statosphere.

EXTERNAL LINKS:

Nasa website: the atmosphere.