What are jet streams?
Jet streams are ribbons of very strong winds which move weather systems around the globe. They are found 9–16 km above the surface of the Earth, just below the tropopause. The position of a jet stream varies within the natural fluctuations of the environment. They are caused by the temperature difference between tropical air masses and polar air masses (PDF, 863 kB). What happens in one part of the world depends on what is happening elsewhere — the atmosphere is a complete environment with numerous connections.
