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For the same numerical value of SPL, the intensity of a plane wave (power per unit area, proportional to mean square sound pressure divided by acoustic impedance) in air is about 20 2 ×3600 = 1 440 000 times higher than in water. Similarly, the intensity is about the same if the SPL is 61.6 dB higher in the water.
The speed of sound is the distance travelled per unit of time by a sound wave as it propagates through an elastic medium. More simply, the speed of sound is how fast vibrations travel. At 20 °C (68 °F), the speed of sound in air, is about 343 m/s (1,125 ft/s; 1,235 km/h; 767 mph; 667 kn), or 1 km in 2.91 s or one mile in 4.69 s.
The SOFAR channel (short for sound fixing and ranging channel), or deep sound channel (DSC), [1] is a horizontal layer of water in the ocean at which depth the speed of sound is at its minimum. The SOFAR channel acts as a waveguide for sound, and low frequency sound waves within the channel may travel thousands of miles before dissipating.
Water pressure also affects sound propagation: higher pressure increases the sound speed, which causes the sound waves to refract away from the area of higher sound speed. The mathematical model of refraction is called Snell's law. If the sound source is deep and the conditions are right, propagation may occur in the 'deep sound channel'. This ...
The type designation "UQC" stands for General Utility (multi use), Sonar and Underwater Sound and Communications (Receiving/Transmitting, two way). The "W" in WQC stands for Water Surface and Underwater combined. The underwater telephone is used on all crewed submersibles and many Naval surface ships in operation.
Figure 1. Table 1's data in graphical format. Although given as a function of depth [note 1], the speed of sound in the ocean does not depend solely on depth.Rather, for a given depth, the speed of sound depends on the temperature at that depth, the depth itself, and the salinity at that depth, in that order.
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In oceanography, a sofar bomb (Sound Fixing And Ranging bomb), occasionally referred to as a sofar disc, [1] is a long-range position-fixing system that uses impulsive sounds in the deep sound channel (SOFAR channel) of the ocean to enable pinpointing of the location of ships or crashed planes.