Question

Write about the composition of the atmosphere

Answer 1

Explanation:

The composition of Atmosphere is said to be a mixture of different gases. It envelops around the Earth. 99% of total mas of atmosphere is confined to highest of 32 km from the Earth’s surface.

Atmosphere is consists of various gases, water vapour and dust particles.

• The presence of oxygen becomes negligible at the height of 120 km from the surface of earth with regards to the composition of atmosphere.
• Carbon dioxide and water vapour occur only upto 90 km.
• Carbon dioxide is meteorically very important as it is transparent to incoming solar radiation but opaque to outgoing terrestrial radiation. It is also responsible for greenhouse effect.
• Ozone gas: 10-50 km above earth surface and acts as filter, absorbing ultraviolet rays from the sun. Ozone prevents the rays from reaching the surface of earth.Water vapour is variable gas, decreases with altitude.

It also decreases from equator towards the poles.

• Acts like blanket allowing the earth to neither to become too cold nor too hot. Also contributes to the stability and instability in the air.
• Dust particles: are in higher concentration in subtropical and temperate regions due to dry winds in comparison to equatorial and polar regions.
• Dust particles act as a hygroscopic nuclei over which water vapour of atmosphere condenses to produce clouds.

The composition of atmosphere varies with local environmental factors also.