Hayashi, Y., 1979: A generalized method of resolving transient disturbances into standing and traveling waves by space-time spectral analysis. Journal of the Atmospheric Sciences, 36 (6), 1017-1029.

Abstract: Space-time spectral formulas are generalized to partition the time power spectrum of transient disturbances consisting of multiple wavenumbers into standing and traveling parts by assuming that these parts are incoherent with each other.
This technique is useful in interpreting the spatial variation of wave amplitude in terms of standing and traveling waves. An example of its application to the analysis of transient planetary waves is given.