Tricellular Meridional Circulation of the Atmosphere - Geography Notes
A three cell model of meridional atmospheric circulation, also known as tricellular meridional atmospheric circulation, in which it is assumed that there is cellular air circulation at each meridian (longitude). The global air circulation can be divided into three cells according to this model. The temperature and kinetic parameters involved with global air circulation have been used to divide these cells. This article will explain to you about Tricellular Meridional Circulation of the Atmosphere which will be helpful in preparing Geography for the UPSC Civil service exam.
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Table of Contents |
Tricellular Meridional Circulation
Atmospheric Circulation
- Atmospheric circulation is the large-scale movement of air that, along with ocean circulation, is used to redistribute thermal energy throughout the Earth's surface.
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| Pressure Gradient and Air Circulation | World Pressure Belts |
| Shifting of Pressure Belts | Wind Direction and Related Laws |
Tricellular Atmospheric Model
- The meridional circulation of the atmosphere is explained by the tricellular model.
- The global air circulation can be divided into three cells according to this model.
- The temperature and kinetic parameters involved with global air circulation have been used to divide these cells.
Tricellular Atmospheric Model
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Hadley cell
- In both hemispheres, the cell is found between 10 and 30 degrees latitude.
- This is a solar cell that has been thermally induced as a result of high solar insolation.
- Along the equator, rising air is caused by high insolation.
- The ascending air cools below the tropopause and forms the anti-trade wind, which blows away from the pole.
- They lead to upper air about 30 degrees latitude, which sinks and causes subtropical high pressure.
- This cell is completed by the trade wind, which travels from the High Pressure toward the equator.
- It's one of the most stable cells, and it's linked to a tropical monsoon and a desert climate.
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Ferrel Cell
- In both hemispheres, this cell stretches from 35 to 60 degrees latitude.
- This is a dynamically generated cell that is thermally indirect.
- Warm air may be seen ascending from the polar front and breaking through near the tropopause in this cell.
- The polar front is more continuous in the middle troposphere, which is the most notable aspect of this cell.
- The tropical and polar front dells both contribute to air subsidence at the horse latitude.
- The westerly wind blowing toward the poleward side completes the circulation on the surface.
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Polar cell
- In both hemispheres, it stretches from 65 to 90 degrees.
- This is a thermally direct cell that is at its most powerful in the winter.
- As the easterly wind travels towards the subpolar low, sinking air moves along the poles.
- The easterly and westerly winds collide at the subpolar lows, causing the air to rise and complete the polar cell circulation.
Significance
- It aids in the formation of doldrums, or the inter-tropical Convergence Zone (ITCZ), the world's most important and continuous belt of convergence.
- The Hadley cell's air circulation manifests itself in the world's tropical deserts.
- The upper air circulation and the trade wind movement have a significant impact on the monsoon phenomenon.
Conclusion
Meridional circulation is also responsible for the formation of tropical cyclones, temperate cyclones, and anticyclones. Above all, it is crucial to comprehend the global climate. Thus meridional circulation not only is an important phenomenon on our planet earth but also in the UPSC Examination.
FAQs
Question: What is the tricellular meridional circulation model?
Answer: The tricellular meridional circulation model explains the large-scale movement of air in the Earth's atmosphere. It consists of three primary cells: the Hadley Cell, the Ferrel Cell, and the Polar Cell, which operate between the equator and the poles, influencing global wind patterns and weather systems.
Question: What role does the Hadley Cell play in atmospheric circulation?
Answer: The Hadley Cell plays a crucial role in tropical atmospheric circulation. Warm air rises near the equator, creating low pressure and converging trade winds. As the air moves poleward, it cools and descends at around 30° latitude, forming a subtropical high-pressure zone, which drives trade winds and influences tropical climates.
Question: How does the Ferrel Cell differ from the Hadley and Polar Cells?
Answer: The Ferrel Cell operates between 30° and 60° latitudes and differs from the Hadley and Polar Cells because it is driven indirectly by the other two. In this region, surface winds move from west to east, creating westerlies, and air is transported poleward near the surface and equatorward at higher altitudes.
Question: What causes the formation of the Polar Cell?
Answer: The Polar Cell forms at high latitudes (60° to 90°) where cold air sinks near the poles, creating high-pressure zones. This cold air flows towards lower latitudes, warms up slightly, and rises again around 60° latitude, where it converges with air from the Ferrel Cell, forming the polar front.
Question: How does the tricellular circulation model influence global weather patterns?
Answer: The tricellular circulation model influences global weather patterns by creating distinct wind belts, pressure zones, and climatic regions. For example, the trade winds in the tropics, westerlies in mid-latitudes, and polar easterlies are direct results of this circulation, affecting weather systems, precipitation, and temperature distributions globally.
MCQs
1. Which of the following cells is responsible for tropical atmospheric circulation?
A) Hadley Cell
B) Ferrel Cell
C) Polar Cell
D) Walker Cell
Answer: A See the Explanation
Explanation: The Hadley Cell is responsible for tropical atmospheric circulation, where warm air rises near the equator, moves poleward, and descends at around 30° latitude, driving trade winds.
2. Which cell operates between 30° and 60° latitudes?
A) Hadley Cell
B) Ferrel Cell
C) Polar Cell
D) Rossby Cell
Answer: B See the Explanation
Explanation: The Ferrel Cell operates between 30° and 60° latitudes, where surface winds move from west to east, forming the westerlies in the mid-latitudes.
3. What is the primary cause of the Polar Cell formation?
A) Rising warm air at the poles
B) Sinking cold air at the poles
C) Converging trade winds
D) None of the above
Answer: B See the Explanation
Explanation: The Polar Cell forms due to sinking cold air at the poles, which creates high-pressure zones. This air flows towards lower latitudes, forming the polar front around 60° latitude.
4. Which winds are created by the Ferrel Cell?
A) Trade winds
B) Westerlies
C) Polar easterlies
D) Monsoons
Answer: B See the Explanation
Explanation: The Ferrel Cell generates westerlies, which are winds that blow from west to east in the mid-latitudes (30° to 60°).
5. What is the effect of the tricellular circulation on global weather?
A) It causes volcanic eruptions
B) It stabilizes ocean currents
C) It shapes wind belts and pressure zones
D) It prevents earthquakes
Answer: C See the Explanation
Explanation: The tricellular circulation shapes global wind belts, such as trade winds, westerlies, and polar easterlies, and creates pressure zones that influence global weather patterns.
GS Mains Questions and Answers
Q1: Explain the structure of the tricellular meridional circulation and its role in global climatic patterns.
Answer: The tricellular meridional circulation consists of three atmospheric cells: the Hadley Cell, Ferrel Cell, and Polar Cell. Each cell plays a role in the vertical and horizontal movement of air across the globe, significantly affecting global climatic patterns. The Hadley Cell, located between the equator and 30° latitude, causes warm air to rise near the equator, creating low pressure and trade winds. The Ferrel Cell, between 30° and 60° latitudes, is indirectly driven by the other cells and generates westerlies. The Polar Cell, between 60° and 90°, involves cold air sinking at the poles and moving towards lower latitudes. Together, these cells create wind belts and pressure zones that influence precipitation, temperature, and weather systems across the globe, leading to distinct climatic regions.
Q2: Analyze the impact of the tricellular circulation model on weather patterns in the tropics and mid-latitudes.
Answer: The tricellular circulation model has a profound impact on weather patterns in the tropics and mid-latitudes. In the tropics, the Hadley Cell generates trade winds and drives convection, leading to tropical rainfall and monsoon systems. It is responsible for creating low-pressure zones near the equator and subtropical high-pressure zones at 30° latitude. In mid-latitudes, the Ferrel Cell generates westerly winds, influencing the movement of weather systems such as cyclones and anticyclones. The interaction between the Hadley and Ferrel Cells also influences the jet stream, which affects the movement of weather patterns in these regions. This circulation model is essential for understanding global precipitation, temperature variations, and seasonal changes.
Q3: Discuss the significance of the Polar Cell in the tricellular circulation model and its effect on high-latitude weather.
Answer: The Polar Cell plays a critical role in the tricellular circulation model by regulating high-latitude weather patterns. In this cell, cold air sinks at the poles, creating high-pressure systems that push air towards lower latitudes. As this air moves equatorward, it converges with air from the Ferrel Cell at around 60° latitude, forming the polar front. The polar front is a key area for the development of low-pressure systems and storm tracks, particularly in the winter months. The Polar Cell contributes to the cold, dry conditions characteristic of polar regions and influences the formation of polar easterlies, which impact weather patterns across high latitudes.
Previous Year Questions on Tricellular Circulation
1. UPSC CSE Prelims 2019:
Question: Which atmospheric cell is responsible for the formation of trade winds?
A) Hadley Cell
B) Ferrel Cell
C) Polar Cell
D) Walker Cell
Answer: A
Explanation: The Hadley Cell, located between the equator and 30° latitude, is responsible for the formation of trade winds, which blow from east to west in the tropics.
2. UPSC CSE Mains 2020 (GS Paper 1):
Question: "Explain the role of the tricellular meridional circulation model in shaping global weather patterns and climatic zones."
Answer: The tricellular meridional circulation model shapes global weather patterns by creating distinct wind belts, such as trade winds, westerlies, and polar easterlies. These wind belts result from the movement of air in the Hadley, Ferrel, and Polar Cells. The Hadley Cell drives tropical weather patterns, including monsoons and trade winds, while the Ferrel Cell is responsible for the westerlies in mid-latitudes. The Polar Cell contributes to the formation of polar easterlies and influences high-latitude weather patterns. Together, these cells create the major climatic zones on Earth, from tropical rainforests to polar deserts.
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