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Air Currents - Coggle Diagram
Air Currents
Global Winds Belts
In the northern hemisphere, hot air in the cell nearest the equator moves to the top of the troposphere.
There, the air moves northward until it cools and moves back to Earth's surface near 30 latitude
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The cell between 30 and 60 latitude is not a convection cell. It's motion is driven by the other two cells.
Three similar cells exist in the southern hemisphere, which help generate the global wind belts.
Earth's rotation causes moving air and water to appear to move to the right in the northern hemisphere, and to the left in the southern hemisphere. This is called the Coriolis effect.
The contrast between high and low pressures and the Coriolis effect creates distinct wind patterns, called prevailing wind.
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When the Coriolis effect acts on the winds, they blow to the east or the west, creating relatively steady, predictable winds.
At about 30 N and 30 S air cools and sinks, which creates areas of high pressure, and light, calm winds at the equator called the doldrums.
Jet streams influence weather as they move cold air from the poles toward the tropics and warm air from the tropics toward the poles.
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Jet streams flow around from Earth from east to west, often making large loops to the north or the south.
Global Winds
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The suns energy warms earth. However, the same amount of energy does not reach all of Earth's surface.
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In latitudes near the equator, sunlights strikes Earths surface at a high angel.
At latitudes near the North Pole and the South Pole sunlight strikes Earth's surface at a low angle.
Sunlight is now spread over a larger surface area than in the tropics. As a result, the poles receive very little energy per unit of surface area and our cooler.
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Over colder areas, air pressure is usually high.
This is because it's so warm in the topics , air pressure is usually low.
Wind is the movement of air from areas of high pressure to areas of low pressure global wind belts influence both climate and weather on Earth.
Local Winds
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A Sea Breeze is wind that blows from the sea to the land due to the local temperature and pressure differences.
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The air over the land warms by conduction and rises, creating an area of low pressure.
The air over the water sinks, creating an area of high pressure because it is cooler.
The differences in pressure over the warm land and the cooler water result in a cool wind that blows from the sea onto the land.
A land breeze is a wind that blows from the land to the Sea due to local temperature and pressure differences.
At night, the land cools more quickly than the water; therefore, the air above the land cools more quickly than the air over the water. As a result, an area of lower pressure forms over the warm water.
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Vocabulary:
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Westerlies: Steady winds that flow from west to east between latitudes 30 N and 60 N, and 30 S and 60 S.
Polar easterlies: Cold winds that blow from the east to the west near the North Pole and the South Pole.
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Sea breeze: Wind that blows from the sea to the land due to local temperature and pressure differences.
Land breeze: Wind that blows from the land to the sea due to local temperatures and pressure differences.
Essential Questions
How does uneven heating of Earth's surface result in air movement? The uneven heating of Earth's surface produces wind because the air temperature and air pressure are different. The differences in the air cause the air to lower pressure.
How are air currents on Earth affected by Earth's spin? The Earth rotates on its axis, circulating air is deflected toward the right in the Northern Hemisphere and toward the left in the Southern Hemisphere. This deflection is called the Coriolis effect.
What are the main wind belts on Earth? The trade winds, the prevailing westerlies, and the polar easterlies.