Abstract
The behaviour of wave energy (projected onto a wave vector) at the lowest critical level (corresponding to the wave vector) is investigated analytically in a linear 3-dimensional framework by the ray tracing method. Both the magnitude and direction of the environmental flow are arbitrary functions of the vertical coordinate, with a slowly varying assumption. The Coriolis parameter is constant. The obtained results show the following. The wave energy infinitely increases only at such a critical level that the magnitude of environmental wind vanishes as a linear function of vertical coordinate, and that the direction of environmental wind does not become perpendicular to the wave vector, and only when the Coriolis effect is ignored. The wave energy remains finite at all other types of critical level. The well-known 2-dimensional non-rotating result that the wave energy infinitely increases at the critical level can not be realized in the 3-dimensional rotating system.
