From AMS Glossary
(Redirected from Azimuthal wavenumber)
(Also called azimuthal wavenumber, hemispheric wavenumber, zonal wavenumber.) In many meteorological contexts, the number of waves of a given wavelength required to encircle the earth at the latitude of the disturbance. If L is the wavelength, r the earth's radius, and φ the geographical latitude, the angular wavenumber k is given by k = 2πrcos φ/L.