What Causes Wind: A Complete Breakdown

Have you ever wondered what makes leaves dance in the air or kites fly high in the sky? All thanks go to the power of wind – our mighty yet invisible friend that shrouds us. 

But what is wind, and what causes it to form?

Let’s uncover everything essential about wind. 

What is Wind?

Wind is the movement of air on Earth caused by pressure variation between two places. 

The wind is invisible and colorless that you cannot touch or hold. 

It is the reason behind the fast transportation of heat, dust, pollutants, and moisture between places.

Types of Wind

You can classify wind into three types Based on the location of occurrence and how frequently they cross that place

• Primary Wind
• Secondary Wind
• Tertiary Wind

Primary Wind or Planetary Wind

You will feel this type of wind passing through a place constantly and in the same direction. Also called prevailing wind, primary wind can be categorised as easterlies, westerlies, and trade winds.  

Secondary Wind or Periodic Wind

Also known as seasonal winds, secondary winds, change their direction as the season changes. Characteristics of this type of wind are defined by the unique geographical location of the place it flows by. An example of a secondary wind is the monsoon wind. Seasonal winds flow in a particular location during a specific season of the year.

Tertiary Wind or Local Wind

Tertiary winds or local winds flow by a small geographical location for a specific time of the day or a year. Based on the geographical condition, tertiary wind can be hot, cold, dust- or ice-rich, driven. This type of wind is induced by the air pressure and temperature variation in the place it passes across. An example of tertiary wind is the Loo- a dry and hot wind flow passing across the northern part of India. Mistral, Bora, Mistral, etc., are a few notable examples of local wind.

What Causes Wind

As explained by the U.S. Energy Information Administration (EIA), winds are caused by the uneven absorption of heat by the Earth’s surface. Hot air extends upward and expands, creating less pressure in that region than in areas where the air is comparatively cooler. Air always moves from a high-pressure to a low-pressure environment and this movement of air creates wind.

Uneven Heating Explained

Let’s understand uneven heating with an example. The land gets heated up faster than seawater. The temperature of the land increases during the day, causing the air above it to heat up. This air is less dense than the air nearby which creates a vacuum effect in the heated air area. To fill this vacuum, seawater steadily moves to this place. This movement creates a chilly breeze. On the other hand, this land eliminates heat at night creating a temperature variation between the offshore and onshore environment. This dip in temperature again creates a pressure difference. This is when a land wind is brought to life! 

Factors Influencing Wind Formation

Several factors influence the formation of wind, including:

• Pressure Gradient: As we know, air flows from high-pressure areas to low-pressure areas creating a wind flow. It means pressure gradient plays a key role in the formation of wind flow.  
• Coriolis Effect: The Earth’s rotation, also called the Coriolis effect plays a key role in the wind formation process. Due to the Earth’s oblate spheroid shape, and its rotation on the axis, you cannot expect windflow to be in the straight direction from one pole to another or between equators. It cannot flow perpendicularly between the poles and the equators, explains the National Oceanic and Atmospheric Administration (NOAA). Rather, wind flows to the right in the Northern Hemisphere and the left in the Southern Hemisphere. It means that the tapered Earth causes wind to flow in a curved pattern. The complex wind pattern is behind the difference in wind direction and water variation across different regions of the world.
• Temperature Variations: As we know, the pressure gradient, the main driving force of wind flow, is created by the temperature gradient – the rate and direction at which the temperature of a particular area changes. It causes the wind to flow and result in different wind patterns. 
• Geography: Moving air is often hindered by landforms – different natural features of the Earth’s surface – and changes its direction. Different landforms include valleys, mountains, etc.
• Friction: Wind flow is often slowed down by the friction that is generated due to the obstacles and surface roughness on the way. This friction also causes wind flow to change its flow pattern and direction.

However, the variation in atmospheric circulation led by the current abrupt climate change can significantly affect wind flow patterns. The result is a change in wind flow speed, pattern and direction, and intensification of the weather system. These alternations can throw the ecosystem off the break, and significantly affect human activities and weather dynamics.

How is WInd Measured?

The instruments commonly used to measure wind are anemometers and wind vanes. With anemometers, you can measure wind speed – the measurement of how fast air moves and wind vanes offer you the wind direction. 

Results of High Wind

High wind can result in: 

• Structural Damage: Extremely high wind can cause severe damage to structures. Roof damage, surface cracks, broken windows, etc., are common damages caused to the structures. In the worst case, the complete structure can collapse due to high wind flow.
• Power Outages: One of the common outcomes of high wind flow is knocked down power lines, leading to whispered outages. This sudden power outage can halt the regular life of the people of the affected locality, disrupting their day-to-day activities.
• Wildfires: Strong winds can fan the flames of wildfires, making them spread faster and get more deadly. One of the examples is the 2018 Camp Fire in California. This havoc wrecked by dry weather was fueled by high wind, and low humidity which caused the deaths of more than 85 people.
• Crop Damage: crops can be damaged, plants can be uprooted, and stems can be broken. The result is decreased agricultural yield, impacting livelihoods. 
• Erosion: Topsoil can be stripped off and-driven erosion can strip off topsoil, leading to land degradation and coastal erosion, affecting ecosystems and infrastructure near the coastline.