## inertio-gravity wave

The dispersion relation is given by frequency in which

*N*is the buoyancy frequency,*f*is the Coriolis parameter, and*k*_{h}and*k*_{v}are the horizontal and vertical components, respectively, of the wavenumber vector**k**. For all wave-numbers, inertio-gravity waves have frequency smaller than*N*and greater than*f*. Their group velocity is perpendicular to the phase velocity such that the vertical component of the group velocity is opposite in sign to the vertical component of the phase velocity. For an upward propagating inertio-gravity wave in the Northern Hemisphere, the perturbation wind vector turns anticyclonically with height.