Jet stream air current

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Students learn about jet streams and explore the effects of the polar-front jet stream on weather conditions in North America.

The jet stream off the East Coast of the United States controls an important climate pattern in the Atlantic Ocean, a new study finds.

The jet stream's swooping path over the Atlantic Ocean is steered by a fluctuating pressure system called the North Atlantic Oscillation (NAO). A positive NAO aims the jet stream toward Ireland, while a negative NAO sends the winds southward, in a pattern similar to the polar vortex of recent winters.

Depending on where the powerful winds cross the Atlantic, the jet stream can have a cooling or warming effect on sea surface temperatures in the North Atlantic Ocean, according to the study, published today (May 27) in the journal Nature.

It is a strong current of air thousands of miles long, hundreds of miles wide , and several miles deep. Jet streams are found in the upper atmosphere, usually above 32,000 feet.

Meteorologists (scientists who study weather and climate in the atmosphere) know that jet streams can travel at hundreds of miles an hour. They were discovered toward the end of World War II by American bomber pilots over Japan and by German reconnaissance aircraft over the Mediterranean.

The first main cause is that the hot air of the tropics rises and moves from the equator toward the North and South Poles. The warm air is pulled toward the cold air just the way steam always rises.