Origin
Air naturally moves from areas of high pressure to areas of low pressure, due to the pressure gradient force. As soon as the air starts to move, however, the Coriolis "force" deflects it. The deflection is to the right in the northern hemisphere, and to the left in the southern hemisphere. As the air moves from the high pressure area, its speed increases, and so does its Coriolis deflection. The deflection increases until the Coriolis and pressure gradient forces are in geostrophic balance: at this point, the air flow is no longer moving from high to low pressure, but instead moves along an isobar. (Note that this explanation assumes that the atmosphere starts in a geostrophically unbalanced state and describes how such a state would evolve into a balanced flow. In practice, the flow is nearly always balanced.) The geostrophic balance helps to explain why, in the northern hemisphere, low pressure systems (or cyclones) spin counterclockwise and high pressure systems (or anticyclones) spin clockwise, and the opposite in the southern hemisphere.
Read more about this topic: Geostrophic Wind
Famous quotes containing the word origin:
“We have got rid of the fetish of the divine right of kings, and that slavery is of divine origin and authority. But the divine right of property has taken its place. The tendency plainly is towards ... “a government of the rich, by the rich, and for the rich.””
—Rutherford Birchard Hayes (1822–1893)
“In the woods in a winter afternoon one will see as readily the origin of the stained glass window, with which Gothic cathedrals are adorned, in the colors of the western sky seen through the bare and crossing branches of the forest.”
—Ralph Waldo Emerson (1803–1882)
“Each structure and institution here was so primitive that you could at once refer it to its source; but our buildings commonly suggest neither their origin nor their purpose.”
—Henry David Thoreau (1817–1862)