Wave shoaling and the angular frequency is proportional to its local rate of change, Simplifying to one dimension and cross-differentiating it is now easily seen that the above definitions indicate simply that the rate of change of wavenumber is balanced by the convergence of the frequency along a ray; Assuming stationary conditions (formula_27), this implies that wave crests are conserved and the frequency must remain constant along a wave ray as formula_28. As waves enter shallower waters, the decrease in group velocity caused by the reduction in water depth leads to a reduction in wave length formula_29 because the nondispersive shallow water
Sound power temperature, the sound power level at distance "r" from the sound source is approximately related to sound pressure level (SPL) by where Derivation of this equation: For a "progressive" spherical wave, where "z" is the characteristic specific acoustic impedance. Consequently, and since by definition , where is the reference sound pressure, The sound power estimated practically does not depend on distance. The sound pressure used in the calculation may be affected by distance due to viscous effects in the propagation of sound unless this is accounted for. Sound power Sound power or acoustic power is the rate at which sound