Pressure Belts of Earth : UPSC Notes

The pressure belts of Earth play a crucial role in shaping the weather patterns, ocean currents, and climate of our planet. In this article, we will explore the various pressure belts of the Earth, their characteristics, and their significance.

What are Pressure Belts?

Pressure belts are regions in the Earth’s atmosphere where the air pressure is relatively uniform. These pressure belts are caused by differences in temperature and humidity that create areas of high and low atmospheric pressure. The movement of air from high-pressure areas to low-pressure areas creates winds, which play a critical role in shaping the weather patterns of our planet.

Equatorial Low Pressure Belt

The Equatorial Low Pressure Belt is a region near the Earth’s equator between the 10 degree N and S latitudes. where the air is warm and moist, and the atmospheric pressure is low. The sun shines vertically over the region throughout the year.

This region is also known as the Intertropical Convergence Zone (ITCZ). The ITCZ is the area where the trade winds from the Northern and Southern Hemispheres converge. Due to the convergence of trade winds, the ITCZ experiences significant amounts of rainfall throughout the year. The Equatorial Low Pressure Belt plays a crucial role in shaping the climate of tropical regions, as it influences the distribution of rain and affects the growth of vegetation.

The other name of the region is Doldrums due to absence of horizontal movement of air.

Subtropical High Pressure Belts

The Subtropical High Pressure Belts are regions of high atmospheric pressure located approximately 30 degrees north and south of the equator. These regions are also known as the Horse Latitudes. The Horse Latitudes are named after the historical practice of throwing horses overboard when ships were becalmed in these regions. The Subtropical High Pressure Belts are characterized by calm winds and clear skies. The sinking air in these regions creates stable atmospheric conditions, which make it difficult for clouds to form. The Subtropical High Pressure Belts are significant because they play a crucial role in shaping the climate of arid regions, such as deserts.

Sub Polar Low Pressure Belt

The subpolar low pressure belt is a region of low atmospheric pressure located around the Earth’s poles, typically between 50 and 60 degrees latitude in both hemispheres. This low pressure zone is formed as a result of the convergence of winds from the subtropical regions and the polar regions. The convergence causes air to rise and creates a zone of low pressure. The phenomenon is called formation of polar front.

During the winter months, the subpolar low pressure belt can intensify and shift towards the equator, leading to stormy weather and high winds in some regions. Conversely, during the summer months, the belt weakens and moves pole ward, resulting in more stable weather conditions in many areas.

Polar High Pressure Belts

The Polar High Pressure Belts are regions of high atmospheric pressure located near the Earth’s poles. These regions are characterized by cold, dry air, and clear skies. The Polar High Pressure Belts play a critical role in shaping the weather patterns of the polar regions, as they influence the movement of polar air masses. During the winter months, the Polar High Pressure Belts expand and move towards the equator, bringing cold, dry air to the mid-latitudes. This can result in the formation of high-pressure systems, which can cause cold and dry weather conditions.

Monsoon Low Pressure Belts

The Monsoon Low Pressure Belts are regions of low atmospheric pressure located in the tropics, which experience seasonal changes in wind direction. The Monsoon Low Pressure Belts are characterized by heavy rainfall during the summer months, and dry weather conditions during the winter months. The Monsoon Low Pressure Belts are significant because they play a crucial role in shaping the climate of many regions, such as India and Southeast Asia

Conclusion

The pressure belts of the Earth are a complex system of atmospheric circulation patterns that play a crucial role in shaping the weather patterns, ocean currents, and climate of our planet. These pressure belts are caused by differences in temperature and humidity, which create areas of high and low atmospheric pressure. The movement of air from high-pressure areas to low-pressure areas creates winds, which transport heat, moisture, and air masses across the continents and oceans. The study of pressure belts is essential for understanding the Earth’s climate system and predicting future climate change.

Summary