CBSE Class 9 Answered

Hi Srinidhi,

The movement of air is caused due to:

• Uneven heating of the atmosphere in different regions of the Earth.
• The atmosphere is heated by re-radiations i.e. the radiations which are reflected back by the land or water bodies. On being heated, convection currents are set in the air which cause the movement of air.

The movement of air from one region to another creates wind.

• The land gets heated faster than water bodies. In coastal areas, during day, the warm air above the land rises and creates a region of low pressure. Air moves from a region of high pressure to a region of low pressure. Hence, there is a regular flow of cool air from the sea to the land i.e. the region of high pressure to the region of low pressure.

• At night, the land cools down rapidly, the area above the land becomes a region of high pressure as compared to the area above the sea and the air starts flowing from the land towards the sea.