Introduction

• The terrestrial system of earth is composed of 4 naturally interacting system i.e.,

i) Lithosphere (about solid substances or masses)

ii) Hydrosphere (about liquid or water)

iii) Atmosphere (about gaseous)

iv) Biosphere (about organic system/life)

• The atmosphere is a mixture of numerous gases. It envelops the earth and extends as far as 960 km above the earth’s surface. This gaseous cover of the earth is held around it by gravitational attraction.
• Like the lithosphere and hydrosphere, the atmosphere too is an integral part of the planet earth and is inseparable from it.
• However, the density of the atmosphere decreases rapidly with the altitude. About 97% of air is concentrated in the lower 29 km.