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Westerlies

earth science Maturity 9-11

Big winds blow across the Earth.

Map prevailing winds on earth.png
Map prevailing winds on earth.png
These winds blow from the west. They move the air and the sea. This helps keep our world warm. Do you feel the wind blow?

36 words

Big winds blow from the west.

Map prevailing winds on earth.png
Map prevailing winds on earth.png
They move across the middle parts of Earth. These winds move air and water.
Franklingulfstream.jpg
Franklingulfstream.jpg
They can carry warm water to land. This helps keep coasts warm. In the south, these winds are very strong. People call them the roaring forties. They blow over the wide, open ocean.
Vientos del oeste.jpg
Vientos del oeste.jpg
The winds move storms from west to east. This helps move weather around the world.

77 words

Westerlies are strong winds that blow from west to east.

Map prevailing winds on earth.png
Map prevailing winds on earth.png
They blow in the middle parts of our world. These winds move between 30 and 60 degrees latitude.
Vientos del oeste.jpg
Vientos del oeste.jpg
They start in high-pressure areas near the horse latitudes. The Earth's spin changes their path. This is called the Coriolis effect. In the north, winds blow from the southwest. In the south, they blow from the northwest.

These winds are very powerful in the Southern Hemisphere. There is much more open ocean there. Without land to slow them down, they stay fast. People call these winds the roaring forties. They can also be the furious fifties. They can even be the shrieking sixties.

Bill 2009 track.png
Bill 2009 track.png

Westerlies move more than just air. They help drive ocean currents. These currents carry warm water toward the poles. In the North Atlantic, the Gulf Stream is a famous current. The westerlies also move storms. These are called extratropical cyclones. The winds steer these storms from west to east. They can even change the path of tropical cyclones. This can turn a storm toward the northeast.

188 words

The westerlies are strong winds that blow from the west toward the east. They live in the middle latitudes of our planet. These winds move between 30 and 60 degrees latitude.

Map prevailing winds on earth.png
Map prevailing winds on earth.png
They start in high-pressure areas called the horse latitudes. These winds are very important for our world's weather. They help move heat and storms across the globe.
Vientos del oeste.jpg
Vientos del oeste.jpg

These winds work because of how the Earth moves. If the Earth did not spin, winds would blow straight toward the poles. Instead, a force called the Coriolis effect changes their path. This effect pulls winds to the right in the Northern Hemisphere. In the Southern Hemisphere, it pulls them to the left. Because of this, northern winds blow from the southwest. Southern winds blow from the northwest.

UK-Cyclone.gif
UK-Cyclone.gif

Scientists study how these winds change with the seasons. The westerlies get stronger when the polar cyclone is intense in winter. They get weaker during the summer months. When pressure is low near the poles, the winds grow strong. This can make the middle latitudes feel much warmer. If pressure is high near the poles, the wind flow changes. This brings much colder air into the middle parts of the world.

These winds are especially powerful in the Southern Hemisphere. There is much more open ocean there than land. Land can slow down the wind pattern, but the ocean does not.

Bill 2009 track.png
Bill 2009 track.png
People give these winds many loud names. They call them the roaring forties between 40 and 50 degrees south. They also call them the furious fifties or the shrieking sixties. In places like Chile and New Zealand, they are called Brave West winds.

The westerlies do more than move air; they move the ocean too. They drive currents that carry warm water toward the poles.

Franklingulfstream.jpg
Franklingulfstream.jpg
In the North Atlantic, the Gulf Stream is a famous current. In the South, the Antarctic Circumpolar Current is the largest. This current flows from west to east around Antarctica. The westerlies also steer big storms called extratropical cyclones. These storms move from west to east across the middle latitudes.

355 words

The westerlies, also called prevailing westerlies or anti-trades, are a major system of global wind patterns. These winds blow from the west toward the east across the middle latitudes of Earth. They are located between 30 and 60 degrees latitude on both sides of the planet.

Map prevailing winds on earth.png
Map prevailing winds on earth.png
These winds are vital because they drive weather systems and move heat around the globe. They act as a massive conveyor belt for both air and ocean water. Without them, the distribution of temperature on Earth would look very different.
Vientos del oeste.jpg
Vientos del oeste.jpg

The movement of the westerlies is caused by a combination of solar heating and Earth's rotation. If the Earth did not spin, solar heating would cause winds to blow straight toward the poles. This would happen as air moves away from the subtropical ridge toward the colder poles. However, the rotation of the Earth creates the Coriolis effect. This effect deflects the path of the moving air. In the Northern Hemisphere, the Coriolis effect pulls the winds to the right. This results in winds that blow from the southwest. In the Southern Hemisphere, the effect pulls winds to the left. This creates winds that blow from the northwest.

UK-Cyclone.gif
UK-Cyclone.gif

The strength of these winds changes based on atmospheric pressure and the seasons. The westerlies are linked to the intensity of the polar cyclone. During the winter, the polar cyclone reaches its maximum intensity. This causes the westerlies to increase in strength. In the summer, the polar cyclone is at its weakest. This causes the westerlies to weaken as well. Pressure levels near the poles also play a major role. When the Arctic oscillation is positive, pressure is lower over the poles. This strengthens the westerlies and warms the middle latitudes. If pressure is higher over the poles, the flow becomes more meridional. This means the wind blows from the pole toward the equator, bringing cold air to the middle latitudes.

Geography has a massive impact on how strong these winds feel. The westerlies are much more powerful in the Southern Hemisphere than in the Northern Hemisphere. This is because there is much less land in the south to slow them down. Land masses can amplify flow patterns and make them more north-south oriented. This slows the west-to-east movement. In the vast oceans of the south, the winds remain unobstructed. Because of the stormy and cloudy conditions, people have given these winds descriptive names. Between 40 and 50 degrees south, they are called the roaring forties. Further south, they are known as the furious fifties or the shrieking sixties. In places like Chile, Argentina, Tasmania, and New Zealand, they are called the Brave West winds.

These winds are responsible for steering extratropical cyclones across the planet. An extratropical cyclone is a large-scale, low-pressure weather system. These systems form in the middle latitudes rather than the tropics. They are often called mid-latitude cyclones or simply depressions. The westerlies steer these systems in a general west-to-east direction.

UK-Cyclone.gif
UK-Cyclone.gif
These cyclones are important because they drive much of the everyday weather on Earth. Sometimes, a tropical cyclone can interact with these systems. If a tropical cyclone crosses the subtropical ridge, it can undergo recurvature. This means the westerly flow catches the storm and turns it toward the pole. An example of this occurred with Typhoon Ioke in 2006.
Bill 2009 track.png
Bill 2009 track.png

The westerlies also drive the movement of the world's great ocean currents. Persistent winds from the west push surface waters toward the east. This process is influenced by western intensification, which makes currents on the western boundaries of ocean basins stronger. In the Northern Hemisphere, the Gulf Stream is a famous example. It is a strong current that helps transport warm, tropical water toward the poles. In the North Pacific, the Kuroshio current acts in a similar way. In the Southern Hemisphere, the impact is even larger due to the open ocean. The Antarctic Circumpolar Current, or West Wind Drift, flows from west to east around Antarctica. At approximately 125 Sverdrups, it is the largest ocean current in the world.

Franklingulfstream.jpg
Franklingulfstream.jpg

Beyond weather and oceans, the westerlies can transport materials across entire continents. For example, dust plumes from the Gobi Desert can be picked up by these winds. The westerlies carry this dust and various pollutants eastward across long distances. This can eventually lead to these materials reaching North America. This shows how connected different parts of the Earth are through the atmosphere. The westerlies serve as a primary link between the tropics, the middle latitudes, and the polar regions. They move energy, water, and even dust in a continuous global cycle.

773 words
🖼️ Images & Media (5)
File:Map prevailing winds on earth.png
Map prevailing winds on earth.png
File:Vientos del oeste.jpg
Vientos del oeste.jpg
File:Franklingulfstream.jpg
Franklingulfstream.jpg
File:UK-Cyclone.gif
UK-Cyclone.gif
File:Bill 2009 track.png
Bill 2009 track.png
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