Explain the mechanism by which the Coriolis effect is a restoring force for long wavelength waves like tsunami

Question

My oceanography text book says the following about the restoration of the sea surface to a flat state following the passage of waves: "Depending on the size of the wave, different restoring forces are involved. For capillary waves, the dominant restoring force is surface tension. The water surface tends to act like a drum head, smoothing out the waves. For waves having periods between 1 second and about 5 minutes, gravity is the dominant force. This range includes most of the waves we see. Such waves are known as gravity waves. Longer waves are restored by the Coriolis effect. For this reason, predictions of tsunami movements or storm surges must include the coriolis effect." An open-ocean tsunami does not represent a flow of water, but rather a flow of energy across the water; how does the Coriolis effect apply? I thought that the Coriolis effect was only valid for particles in motion. Does that mean that the Coriolis effect applies to other waves, like radio waves? Why?

Answer 1

The Coriolis effect applies to anything that moves in a straight line within a rotating frame of reference, whether it is an object or some kind of impulse. On an object the size of the Earth, the impact of the Coriolis effect is only seen with objects that have very large-scale motion, such as a hurricane, the jet stream, or a tsunami.

The reason why the Coriolis effect is significant for tsunamis but not for radio waves is that the radio waves move at the speed of light. That means that the rotation of the Earth is extremely small during the time that the radio wave is traveling to its destination, so any deflection of the wave would be similarly small.

Furthermore, the Coriolis effect is part of classical mechanics, which is only valid for objects that are larger than atoms and for velocities that are much smaller than the speed of light. As a result, it cannot be applied to observations of a wave that moves at light speed. The movement of radio waves is governed by quantum mechanics.

Answer 2

in the northern hemisphere the water from the tsunami will rotate in a counter-clockwise route and in the southern hemisphere that's going to rotate in a clockwise route. (each each now and then I wonder myself.) j0e