Using the argument of the Airy function as an analysis tool in ocean acoustics and oceanography

By assuming the index of refraction is linear between layers, it is possible to convert the depth dependent acoustic Helmholtz equation into an Airy equation. Decades ago this allowed the ocean acoustic pressure to be quickly calculated using tables of precalculated Airy functions with interpolation. High speed computers and the accurate parabolic equation model have rendered the Airy equation approach as a curiosity of history. However, the method can still be useful as an assessment tool. This has been demonstrated by using it to select similar ocean environmental parameters that have the same acoustic propagation characteristics. In this presentation, we apply the Airy equation method to evaluate the buoyancy frequency of similar ocean environments that support internal waves. A connection is made between the ocean acoustic propagation and the oceanography of the similar regions.