WHAT IS THE JET STREAM

WHAT IS THE JET STREAM?
Nowadays, the word ''jet'' is very much in the news, and you might imagine that the ''jet stream'' has something to do with jet planes. This isn't the case at all!
The jet stream is part of the system of winds that surround the earth, so let;s start with the subject of winds. Wings are currents of air that move parallel to the surface of the earth and close to it.

The movement of winds is chiefly caused by the existence of areas of different pressure, and winds always blow from areas of high pressure to areas of low pressure.

If we look at it from an over-all point of view (not from local region) we can say that, in general, cold air is transported from the poles toward the Equator, and warm air from the Equator toward the Poles. This flow doesn't take place in smooth surrents, but forms a system of rather turbulent streams. There are various conditions that decide what happens in each specific region. There may be local sources of heat which affect the pressure.The way the land and water and mountains are distributed can decide which way the local winds blow.
Finally, there is the existance of semi-permanent.