Surface Waves

Ocean surface waves are the most studied and well known waves on the earth. If the restoring force for surface waves is the gravity, the waves are called surface gravity waves. If the restoring force is surface tension waves are called capillary waves (usually very short waves). If both gravity and surface tension play a leading order role, waves are called capillary-gravity waves.

Oceanic and Atmospheric Waves











Waves in the Atmosphere and Oceans of Other Planets?

Yes, surface and internal waves exist on the surface and within the atmosphere of other planes. They result in numerous mysterious phenomena observed by the spacecrafts but not yet clearly explained.

Jupiter Waves and Currents
This wave cloud pattern formed over the Īle Amsterdam, in the lower left corner at the tip of the triangular formation, in the far southern Indian Ocean.
Internal Waves in Rosario Strait North Puget Sound Washington (credit)
Powerful Waves vs Lighthouse
(Photo: Jean Guichard)

What are Internal Waves?

The density of water in an ocean or a sea is typically not constant. The variation of density is due to, mainly, variations of temperature and salinity. Solar radiation heats up the upper layer of the water, and the flow of rivers and the melting of ice lower the water density near the surface. Over time these effects add up to form a stable density stratification with the lighter fluid on top and the denser fluid below it. Stratified waters, besides regular surface waves, admit the so-called internal waves, which are gravity waves that propagate within the body of the water.

Because internal wave propagate under the water surface we cannot see them directly (just by measurement), but their motion leaves a very distinguished trace on the surface that can be seen or tracked by satellite. The oblique strips in the above photo are indicators of passage of oceanic internal waves underneath the water surface.

South China Sea Internal Waves as seen by NASA's Shuttle- June 1983

Atmospheric Internal Waves

Atmosphere stratification has been known for a much longer time and results in important and interesting phenomena in the atmosphere

Saturn's mysterious hexagon is a very stable structure near Saturn's north pole and is the  one of the most bizarre phenomenon seen in the solar system (credit)