ABSTRACT
a band of very strong winds, up to 250 km per hour, occurring in certain locations in the upper atmosphere. A jet stream may be hundreds of kilometers in width, with a vertical thickness of one to two thousand meters. On average they can be found at altitudes of 10,000 meters. They are the product of a large temperature gradient between two air masses that have markedly different temperatures. There are two main locations of jet streams:
the Polar Front jet – a westerly band associated with the meeting of polar and tropical air above the Atlantic Ocean at approximately latitude 60°N and 60°S. The precise location of this jet stream varies on a daily basis, but airplane pilots may seek to “ride” in it when going from west to east, and to avoid it when flying from east to west
the Sub-Tropical jet – also generally westerly and associated with the poleward ends of the Hadley cells at approximately 25°N and 25°S. However, in summer above West Africa and southern India this jet may become easterly. This is due to temperatures over the land in these areas being higher than over the more southerly sea areas.
