Intrinsic wave frequency

From Glossary of Meteorology

intrinsic wave frequency

The frequency of oscillation measured by a sensor that moves with the mean wind.

If a wave of wavelength λ has intrinsic frequency fi and is imbedded in a mean wind speed of U, then the local wave frequency f in Hz measured by a sensor fixed to the ground is
This relationship applies to internal gravity waves in the atmosphere. A special case is for standing mountain waves (in which occur lenticular clouds) where f = 0, because the intrinsic frequency exactly counteracts the wind effect.