How air pressure is important for blowing of the wind

What is wind?

The wind is nothing but air molecules floating around.. This is what gives wind its mass or substance. When it’s windy all those molecules are moving like a herd. Sometimes they float gently in a breeze and other times like in a hurricane moving along at hundreds of miles an hour. The air pressure is what dictates whether the wind is strong or weak. It is the force with which air molecules push against us and everything around us. When the air pressure changes so do the strength of the wind.

What makes air pressure change?

The height above sea level, the temperature and the amount of water vapor in the air. These three things make air dense. When the air gets colder and closer to sea level it gets denser. It means the air molecules are closer together and there is more air pressure. When the air gets warmer and higher there’s less air pressure and the air molecules are farther apart or less dense. Dense air will sink, while less dense air will rise and create a vacant space. The pattern of rising and falling air is called a convection cell.

How does Convection cell work?

Say we’re at the beach, in a convection cell the air over the sea cools and sinks, that’s a downdraft. At the same time the air over the land gets warmer and rises, that’s an updraft. The cool high-pressure air moves towards the land and heats up, replacing the warm air. The warm low-pressure air moves out to sea and cools replacing the cool air. This is how the movement of air is caused.

The role played by the Earth’s rotation

The air movement is affected by one more thing, the Earth’s rotation. As the Earth spins it pulls the wind and makes it travel on a slightly curved path from west to east or east to west. This process is known as the Coriolis effect. There are different kinds of winds and they have different names like breeze, gust, polar easterlies, prevailing westerlies, trade winds, etc. Polar easterlies are winds that come in from the poles and blow east to west. Prevailing westerlies are warmer winds blowing in the middle latitudes and trade winds are near the equator.

Summary

So, we have learned that wind is caused by changes in air pressure. The air pressure is affected by three things, temperature, height above sea level and amount of water vapor in the air. The convection cells concept deals with hot air rising and cool air sinking. The Coriolis effect that is a result of the spinning of the earth makes the winds curve.