The density and the Aux of wave-activity conservation laws are generally required to satisfy the group-velocity property: under the WKB approximation (i.e., for nearly monochromatic small-amplitude waves in a slowly varying medium), the flux divided by the density equals the group velocity. It is shown that this property is automatically satisfied if, under the WKB approximation, the only source of rapid variations in the density and the flux lies in the wave phase. A particular form of the density, based on a self-adjoint operator, is proposed as a systematic choice for a density verifying this condition.
|Number of pages||6|
|Journal||Journal of the Atmospheric Sciences|
|Publication status||Published - 15 Mar 1998|
- LONG STATIONARY SOLUTION
- ACTIVITY DIAGNOSTICS