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The air at the equator is headed east with the Earth at 1000mph. As the tropical sun heats the air, it rises, and cooler air from both north and south roll in to fill the void. the air filling the void is rotating with the Earth slower than the air it replaces, so it heads West at a slow speed.
The hot air that has risen heads north and south, and falls to earth moving east substantially faster than the surface of the earth. These are the constant easterly tradewinds.
This process repeats itself with belts of warm and cool air all the way to the poles, though the wind speeds become smaller there.
In the temperate belts, the air temperature isn't as great a differential, so the belts get wider, and the differential speeds of the airstreams even higher. Though water, land obstructions, and other topographic features keep the bands from being colinear with latitude, the speed of the air travelling north and south results in a band of high velocity wind headed east at temperate latitudes. This band drops toward the equator during winter and travels away from the equator during summer. During the reversal of seasons, the jetstream can be remarkably "fixed", but, inevitably, it begins to move toward the equator once again.
This high altitude movement, combined with an understanding of the air movement underneath it, explains why surface winds can often travel in the opposite direction from those aloft.
For me, at 34 degrees N, the surface winds often blow from east to west when the upper atmosphere is moving the opposite direction.
To research this further, look up "Coriolis Effect", "Jet Stream" "Atmospheric bands" or "atmospheric movement".
Don
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