<span>The
speed of sound fluctuates with changes in depth that go with regular changes in
salinity, temperature and pressure in the ocean. They may both form a coat of shadow,
layers of reflection when the waves are propagated. The greater the temperature
of the water, the faster the sound travels for narrower depths. But deeper into
the ocean, pressure dominates. The thermocline where the change of temperature
is greatly observed, shows a decrease in sound speed with decreasing
temperature. The region somewhere in the thermocline where the sound speed is
at minimum and allows the transmission of low frequency sound at great distances
is called SOFAR or sound fixing and ranging channel. SOFAR channels is greatly
affected with depth and thickness.</span>
Water stratification is a phenomenon in which regions of water with different properties, such as salinity, oxygen content, density and temperature, form barriers to mixing of the water.
These barriers also create channels, referred to as sound fixing and ranging (SOFAR) channels. In these channels, the sound has a specified path. It travels slower than normal, but due to reduced dissipation to the surroundings, the sound travels for larger distances.
