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Jet stream

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Jet streams are fast-flowing, narrow currents of air in the atmosphere.

Straalstroom
Straalstroom

These winds move from west to east around the entire globe. They are vital to our planet because they help drive weather patterns and influence climate. Most terrestrial jet streams are located near the altitude of the tropopause. The tropopause is a boundary layer in the atmosphere. Jet streams can be continuous over very long distances. However, they can also start, stop, or split into multiple parts. They might even flow in directions opposite to the rest of the stream.

Jetstreamconfig
Jetstreamconfig

These powerful winds are created by two main physical factors. First, solar radiation heats the Earth, which creates large-scale circulation cells. These include the polar, Ferrel, and Hadley cells. Second, the rotation of the planet creates the Coriolis force. This force acts on moving masses of air to change their direction. The jet stream forms at the boundaries where these circulation cells meet. For example, the polar jet forms between the polar and Ferrel cells. The subtropical jet forms between the Ferrel and Hadley cells.

Earth Global Circulation - en
Earth Global Circulation - en

There are different types of jet streams depending on their location and strength. The polar jet stream is usually found between 30 and 60 degrees latitude. It is often located near the 250 hPa pressure level. This means it sits at about one-quarter of the way up the atmosphere. The polar jet is very important for aviation and weather. In the Northern Hemisphere, the jet "follows the sun" by migrating. It moves northward as the hemisphere warms and southward as it cools. The subtropical jet is located closer to 30 degrees latitude. It is somewhat higher and weaker than the polar jet.

Jetcrosssection
Jetcrosssection

Jet streams do not move in straight lines. Instead, they often follow a meandering, wavy path. These large meanders are known as Rossby waves, or planetary waves. They are caused by changes in the Coriolis effect at different latitudes. Within these large Rossby waves, there are also smaller waves called shortwave troughs. These troughs move along the flow pattern around large-scale ridges and troughs. The wind speeds are highest where the temperature differences between air masses are greatest. In these areas, speeds can exceed 400 kilometers per hour. Some measurements have recorded even higher speeds.

Jetstream - Rossby Waves - N hemisphere
Jetstream - Rossby Waves - N hemisphere

Humans have been discovering and studying these winds for a long time. In the 1800s, American professor Elias Loomis proposed a hypothesis about powerful upper-air currents. After the 1883 eruption of the Krakatoa volcano, observers tracked a "smoke stream" of dust. This dust moved westward around the equator in a rapid current. In the 1920s, Japanese meteorologist Wasaburo Oishi detected the jet stream near Mount Fuji. He used pilot balloons, or "pibals," to measure wind speed and direction. American pilot Wiley Post also noticed the jets while flying solo around the world in 1933. He used a pressurized suit to fly at high altitudes.

Greatcircle Jetstream routes
Greatcircle Jetstream routes

Understanding jet streams has many practical uses today. Meteorologists use the location of these streams to help forecast the weather. For instance, if the polar jet stays too far south, it can cause severe flooding. In 2007 and 2012, Britain experienced major flooding due to this shift. Airlines also use jet streams to reduce flight times and save fuel. During World War II, the Japanese used the jet stream to carry Fu-Go balloon bombs across the Pacific. Scientists are even looking into whether these winds could be used for power generation.

El nino north american weather
El nino north american weather

Jet streams are not unique to Earth. Scientists have detected them in the atmospheres of several other planets. These include Venus, Jupiter, Saturn, Uranus, and Neptune.

Hubble Takes Close-up Portrait of Jupiter
Hubble Takes Close-up Portrait of Jupiter

On these gas giants, the winds play a major role in their atmospheric structure. On Earth, phenomena like the El Niño–Southern Oscillation can change where jet streams are located. This change affects the weather in the tropical Pacific and the climate of the tropics. It can even change weather in higher-latitude regions. This shows how closely the jet streams are connected to the entire global climate system.

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🖼️ Images & Media (10)
Aerial Superhighway.ogv
File:Straalstroom.jpg
Straalstroom.jpg
File:Jetstreamconfig.jpg
Jetstreamconfig.jpg
File:Jetcrosssection.svg
Jetcrosssection.svg
File:Earth Global Circulation - en.svg
Earth Global Circulation - en.svg
File:Jet Stream Rigs Apart Flossie 2.jpg
Jet Stream Rigs Apart Flossie 2.jpg
File:Greatcircle Jetstream routes.svg
Greatcircle Jetstream routes.svg
File:El nino north american weather.png
El nino north american weather.png
File:Jetstream - Rossby Waves - N hemisphere.svg
Jetstream - Rossby Waves - N hemisphere.svg
File:Hubble Takes Close-up Portrait of Jupiter.png
Hubble Takes Close-up Portrait of Jupiter.png
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