INTERNAL WAVES
Internal waves most often arise at a boundary between water layers of different densities, where the particles of a water are in a condition of a steady-state equilibrium. Particles oscillate under the influence of wind and tidal waves, synoptic eddies, changes in atmospheric pressure and other phenomena. The oscillations are spread in denser water as internal waves with heights of 20-100 m. Their lengths can vary from hundreds meters up to several kilometres, and their period, from several minutes up to tens of hours. Internal waves react to cyclical changes of temperature and salinity at depth. Sometimes, during period of calm or weak winds they are observed in alternating, smooth bands on the surface of the Ocean. These bands are located above troughs of internal waves.

Internal waves influence the navigation of submarines, the overall performance of acoustic devices, migration of plankton and fish, etc.
 
 

Development scheme of an internal wave

1. Smooth bands

2. Oceanographic devices