Zonal Wave Pattern

A zonal wave pattern describes the east-west wave structure in an atmospheric or oceanic field, quantified by the zonal wavenumber, the number of complete wavelengths fitting around a latitude circle. Wavenumber 1 has one ridge and one trough around the globe, and wavenumbers 1 to 3 are the long planetary Rossby waves that meander the jet stream; wavenumbers 4 to 10 are synoptic-scale waves. In the Northern Hemisphere wavenumbers 1 and 2 are forced by topography such as the Rockies and Tibetan Plateau, while the Southern Hemisphere shows a persistent wavenumber 3. The pattern sets the position of storm tracks that drive marine wind and wave fields.