Planetary Winds

Wind is the air movement generated by pressure changes inside our atmosphere. Wind moves from an area of high air pressure to an area of low air pressure, thus balancing the air pressure differences. The greater the pressure differential, the faster the wind will flow. 

Planetary winds are the type of winds that blow continuously in the same direction from high-pressure belts to low-pressure belts. They sweep across countries and oceans. There are three types of planetary winds: trade winds, westerlies, and polar easterlies. These are pressure belt-controlled. Generally, these winds flow from east to west, the point where this meet is termed as convergence zones.

What are the types of winds?

Primary wind or Planetary winds: Primary winds blow continuously in a particular direction throughout the year. Additionally, primary winds are referred to as planetary winds or prevailing winds. Primary winds include trade winds, westerlies, and easterlies.

Secondary winds: Secondary winds are seasonal winds that alter direction. A secondary wind and the underlying forces that propel it are unique to each geographic region. The monsoon wind is one of the most well-known secondary winds. These are also known by the name of periodic winds.

Tertiary wind: These flow in an area over a specific time of the year. These winds blow due to a location’s temperature and air pressure differences. These winds might be classified as hot, cold, ice-filled, or dusty, depending on their local features. Loo is a dry and hot local wind found in India’s northern plains. Other significant local winds include the Mistral, Foehn, and Bora.

This classification system is based on the occurrence’s frequency and location

Planetary Winds

These pressure belt-controlled winds blow in the same direction year-round. The planetary wind is classified into trade winds, westerlies, and polar winds. Thus, the following are the properties of planetary winds:

• These pressure belt-controlled winds blow in the very same direction year-round.
• Planetary winds are frequently referred to as prevailing or constant winds.
• Throughout the year and in a certain direction, they flow from high to low pressure over the Earth’s surface and oceans.

What are the types of Planetary winds?

Trade Winds (Tropical Easterlies)

These trade winds are the winds that blow from subtropical high-pressure areas to the equatorial low-pressure belt. As a result, these are limited to a portion of the Earth’s surface between 30°N and 30°S. They move through the northern hemisphere as the north-eastern trades and the southern hemisphere as the south-eastern trades. This deflection away from their ideal north-south direction is understood by Coriolis force and Farrell’s law.

The trade winds drop and remain stable in their origin area, but they grow humid and warmer as they approach the equator due to the moisture they gather up along the route. At the equator, the trade winds from both hemispheres meet and, as a result of convergence, they ascend and cause heavy rain. Along with cool ocean currents, Eastern trade winds are drier and more steady than Western ones.

The Westerlies

These winds are also referred to as Westerlies, Furious Fifties, Shrieking Sixties, and Roaring Forties. They blow from subtropical to subpolar high-pressure bands. The southern hemisphere’s westerlies are more robust and consistent than the northern hemisphere’s.

The westerlies’ primary qualities can be summarised as follows:

• Winds move from subtropical highly pressurised belts to low pressure belts in the subtropics.
• In the Northern Hemisphere, the wind blows from S – W to N – E due to the Coriolis effect; in the Southern Hemisphere, the wind blows from N – W to S – E due to the Coriolis effect.
• Winds blow from lower to higher latitudes.
• Cause significant rainfall, particularly on the continents’ western edges.
• Due to fewer barriers from continents, the S – Hemisphere winds are more steady in direction and blow with more force.
•  They are additionally referred to as bold winds, roaring forties, furious fifties, and screeching sixties, depending on the severity of the storms in the latitudes where they blow.

It should be mentioned that not all of the temperate zone’s western coast (30* – 60*) receives year-round Westerlies due to the changing of wind belts caused by the Earth’s tilt.

Polar Easterlies

Polar Easterlies are cold, dry, persistent winds that flow from north-east to south-west in the Northern Hemisphere and from south-east to the north-west in the Southern Hemisphere. Easterlies originate in the subpolar lows’ high-pressure polar zones.

Significant characteristics include the following:

• Winds move from the polar high-pressure zone to the subpolar low-pressure zone.
• They are extremely frigid in nature. They originate in arctic regions and do not produce a lot of rain; when these winds collide with westerlies, they form cyclones.
• Brings about frequent changes in weather conditions and results in torrential rain.

Conclusion

Also known by the name of prevailing winds, these are the winds that flow throughout the year on the Earth in the same direction. Three types of planetary winds further distinguish their categories.