write a short note on the main features of the composition of atmosphere
Answers
Answer:
The atmosphere is composed of gases, water vapour and dust particles. This composition of the atmosphere is not static. It changes according to the time and place. The proportion of gases varies in the higher layers of the atmosphere so that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the earth’s surface.
Explanation:
Earth is enveloped by a deep blanket of gases extending several thousands of kilometres above its surface. This gaseous cover of the earth is known as the atmosphere.
Compared to the earth’s radius, the atmosphere appears to be only a very thin layer of gases. However, because of the force of gravity, it is inseparable from the earth.
Composition of atmosphere
The atmosphere is a mixture of many gases. In addition, it contains huge numbers of solid and liquid particles, collectively called ‘aerosols’.
Some of the gases may be regarded as permanent atmospheric components which remain in fixed proportion to the total gas volume.
Other constituents vary in quantity from place to place and from time to time. If the suspended particles, water vapour and other variable gases were excluded from the atmosphere, then the dry air is very stable all over the earth up to an altitude of about 80 kilometres.
The proportion of gases changes in the higher layers of the atmosphere in such a way that oxygen will be almost in negligible quantity at the height of 120 km. Similarly, carbon dioxide and water vapour are found only up to 90 km from the surface of the earth.
Nitrogen and oxygen make up nearly 99% of the clean, dry air. The remaining gases are mostly inert and constitute about 1% of the atmosphere.
Besides these gases, large quantities of water vapour and dust particles are also present in the atmosphere. These solid and liquid particles are of great climatic significance.
Different constituents of the atmosphere, with their individual characteristics, are discussed below