What is Wind?
‘Wind’ is the flow of a huge amount of air, usually from a high-pressure area to a low-pressure area.
How is wind created?
Creation of wind begins with the sun’s radiation falling on earth’s surface. The earth has two main components: land and water. These components are unevenly heated and cooled. Land heats as well as cools faster than water. As a result of this uneven heating and cooling, the earth surfaces will vary a lot in temperature. And this difference in the temperature between the land and water creates winds.
Let us understand how.
In the coastal regions, during the day, land gets heated faster than the sea. Warm air being light rises, creating low pressure above the land. As the air above the sea is cooler and denser as compared to the land, high pressure is created above the water. We know that wind moves from high-pressure areas to the low-pressure areas. Therefore during the day, the denser air over the sea will move to take the place of the air that has risen up above the land. This will cause movement of air molecules which we call the Wind! During the day, the wind blows from the sea to the land so we call it the sea breeze.
Sea breeze
During the night time, the land cools faster than the water. Hence at night, the temperature of the water is higher than that of the land. Now the air above the water has risen up and has created a low-pressure zone while that of land has created a high-pressure zone. The air will now move from land to sea as the pressure on land is higher than the air pressure over the water. This movement of wind from the land to the sea is called the land breeze.
Land breeze
What are Convection currents?
We now know that the wind moves in a pattern. The air above the land gets heated and rises upwards, further gets cooled and comes down once again to take the place of the risen hot air. These are called Convection currents.
In simple words, it is the upward movement of warm air and the downward movement of cool air because the hot air rises after expanding due to heat and the cool air sinks, thus creating a cyclical movement.
Convection currents
Which are the factors that affect the movement of the wind?
- Temperature
- Physical barriers like mountains
- Rotation of earth