1. Composition of the Atmosphere

In general, atmosphere is a layer of gases and dust surrounding a planet that is held in place by the gravity of the planet body. An atmosphere is more likely to be retained if the gravity is high and the atmosphere's temperature is low. In fact, earth’s atmosphere makes earth unique in the solar system. Planet Earth’s atmosphere is best suitable for life and thus, it is important to understand the composition as well as structure of it. In this context, man has started studying the atmosphere thousands of years before. The Rig Vedic verses have mention of Monsoon, seasons etc.

important properties of the atmosphere such as temperature and pressure, can vary

considerably in both time and space, its composition in terms of the relative proportions of the gases present in any unit volume, tends to remain remarkably constant. Thus, the atmosphere generally tends to act very much as a single gas, which we commonly known as ‘air’. The horizontal variation in the per cent share of these components of atmosphere has less variation as compare to vertical variation.

1.1. Gases

Earth’s atmosphere is composed of gases, water vapours and dust particles. Although other

The main component gases of dry air are listed in Table 1. It should be noticed that nitrogen and oxygen together make up about 99 per cent of the volume, and that the other one per cent is chiefly Argon. Other gases such as Methane, Ozone are found in traces.