Hayashi, Y., 1979: Space-time spectral analysis of rotary vector series. Journal of the Atmospheric Sciences, 36 (5), 757-766.

Abstract: The analogy between space-time spectra and rotary spectra is discussed. The space-time spectra can be interpreted as the rotary spectra of a wave vector. These spectra are combined to resolve a rotary vector into clockwise and anticlockwise components as well as progressive and retrogressive components. The space-time rotary spectrum analysis is useful for a statistical identification of traveling vortices.