Atmosphere And Weather

What is the Coriolis Force

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Without the Coriolis Force, the Earth, as a perfectly circular rotating body, would have all of the existing water and air propelled toward the Equator, where it would remain. The Coriolis effect was first described in 1835, by Gaspard-Gustave Coriolis, a French scientist.

Gustave Coriolis demonstrated that, Newtons laws of motion - with an inertial force rotating counter-clockwise or to the left for regular rotation - must be included in other equations of motion. Gustave Coriolis noted that the components of constant gravity that are at right angles to the Earth's axis provides the force needed to keep matter, seen and unseen, in the same position.

Each element of constant gravity has a different conclusion: the conclusion of the right angles (to the objects at the surface) is that each object stay where it is supposed to, instead of veering toward the Equator, which is the natural place for them to go. The Coriolis effect is most apparent in the path of an object moving North to South.

On the Earth, an object that moves along the North-South direction will be drawn to the right in the Northern Hemisphere and to the left in the Southern Hemisphere.

There are two reasons for the altered path; 
1] The Earth rotates toward the East
2]  The velocity at the North and South poles are close to non-existent. Velocity at the Equator is at the maximum.

Because of the velocity at the Equator, an object fired at a target  to the North (from the Equator) would not go in an apparent straight line, it would be pulled to the East - instead of going straight Northward. This 'pull' happens because the object was moving Eastward faster at its starting point - the Equator, than the target that was situated North. In other words, the target has moved.

No matter the direction, at the Equator a propelled object will not and cannot follow a straight line. This deflection is absolutely related to the motion of the propelled object, the rotation of the Earth as well as the latitude. The Coriolis effect is also a controlling factor in the directions and rotation of sunspots.

An  airplane that take off from Alaska headed directly toward Fort Lauderdale, Florida would not make it to that point, due to the Coriolis force. Fort Lauderdale would not be in the same place as it was, when the plane took off - because of the rotation of the Earth.  The plane would land to the right of Fort Lauderdale. The same is true for an airplane flying in the opposite direction. Pilots consider the Coriolis Force when headed to their destination.

The Coriolis force also play a major part in meteorology, physical geology and oceanography. Since the Earth is rotating, movement over the surface of the Earth will be affected greatly by the Coriolis Force. Put simply, as air flows, the Earth is rotating under it, making the wind flow in a curved path. In the North it flows to the right, in the South, it flows to the left. Directly at the Equator, the actual force of the Coriolis force is at its weakest point, close to zero.


1] NWS.NOAA.Gov/om/educ/activit/coriolis.htm




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