What is global circulation? | Part Three | The Coriolis effect & winds

Summary

This video explains the global atmospheric circulation, which is split into three cells per hemisphere: Hadley, Ferrel, and Polar cells. It explores how the Coriolis effect, caused by Earth's rotation, influences winds and jet streams, creating prevailing wind patterns and strong eastward jet streams. The video details how the spin of the Earth causes winds to deflect in different directions in the Northern and Southern Hemispheres. It also covers how the Coriolis effect contributes to trade winds, westerlies, and the formation of powerful jet streams, impacting weather patterns. The video concludes by comparing Earth's circulation to Jupiter's, highlighting the differences in rotation speed and atmospheric structure.

Takeaways

• 🌍 Earth's atmospheric circulation is divided into three main cells: the Hadley, Ferrel, and Polar cells.
• 🌪️ The Coriolis effect causes moving air to be deflected to the right in the northern hemisphere and to the left in the southern hemisphere.
• ⚖️ The Coriolis effect occurs because the Earth's surface moves faster at the equator than at the poles due to its larger circumference.
• 🌬️ Winds are deflected by the Coriolis effect, which influences wind patterns like trade winds and jet streams.
• 🌐 Air moving from the equator towards the poles gets deflected eastward, while air moving southward towards the equator is deflected westward.
• 🌫️ The Coriolis effect is responsible for the rotation of winds around high and low-pressure systems: clockwise in the northern hemisphere and counterclockwise in the southern hemisphere.
• ✈️ Jet streams, such as the subtropical jet stream, form due to the deflection of air by the Coriolis force, moving eastward at high altitudes.
• 🌪️ The polar front jet, which forms between cold polar air and warm tropical air, is stronger in winter due to larger temperature contrasts.
• 🌀 Surface winds in the Hadley cells, known as trade winds, blow towards the equator and are deflected westward, creating northeast and southeast trade winds.
• 🌍 Similar to Earth, Jupiter experiences the Coriolis effect, leading to multiple atmospheric circulation cells and a distinctive banded appearance due to its rapid rotation.

Q & A

What are the three main atmospheric circulation cells in each hemisphere?

The three main atmospheric circulation cells in each hemisphere are the Hadley cell, Ferrel cell, and Polar cell.

What is the Coriolis effect and how does it affect wind patterns?

The Coriolis effect is the deflection of moving air due to the Earth's rotation. In the Northern Hemisphere, it causes winds to curve to the right, and in the Southern Hemisphere, it causes winds to curve to the left.

Why does the Earth's surface rotate faster at the equator than at the poles?

The Earth's surface rotates faster at the equator because the Earth is wider at the equator, so it covers more distance in one day compared to the poles.

How does the Coriolis effect influence air movement near the poles and the equator?

As air moves away from the equator, it is deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. This causes air to move in a curved path instead of a straight line.

What is the relationship between the Coriolis effect and the movement of jet streams?

The Coriolis effect causes air moving away from the equator to speed up as it gets closer to the Earth's spin axis, forming jet streams. These jet streams flow eastward at high altitudes.

What is the difference between the Subtropical Jet Stream and the Polar Front Jet Stream?

The Subtropical Jet Stream occurs between the Hadley and Ferrel cells, while the Polar Front Jet Stream forms between the Polar and Ferrel cells. The Polar Front Jet is stronger during winter due to temperature contrasts between polar and tropical air.

What factors influence the strength of the Polar Front Jet Stream?

The strength of the Polar Front Jet Stream is influenced by the temperature contrast between cold polar air and warm tropical air. It is stronger in winter when this contrast is greater.

How do the jet streams affect weather systems, particularly in the UK?

The jet streams can steer weather systems, such as Atlantic depressions, toward regions like the UK, causing them to deepen and bring storms.

What are trade winds, and how do they form in Earth's atmosphere?

Trade winds are persistent winds that flow towards the equator. They form due to the deflection caused by the Coriolis effect as air flows from the Hadley cells towards the equator.

How does Jupiter’s atmosphere compare to Earth's in terms of circulation and the Coriolis effect?

Jupiter's atmosphere has similar circulation cells due to the Coriolis effect, but because of Jupiter's faster rotation and larger size, the Coriolis effect is much stronger, leading to more distinct circulation patterns and a striped appearance.