A Space–Time Analysis of Tropospheric Planetary Waves in the Northern Hemisphere

Abstract

The propagation of planetary waves at the 500 mb level is investigated by applying an extended version of wavenumber-frequency analysis. By separating the variance attributable to wave disturbances from the total variance, one may account for the noisy character of atmospheric motions. Several possible representations of zonal wave motions are discussed. The global morphology of the spectra of geopotential is given using a separation into westward and eastward traveling waves, and the differences to previous analyses are elucidated. It is shown that the traveling character of the waves dominates for nearly all latitudes and wavenumbers. The latitudinal and wavenumber bands where westward or eastward traveling waves prevail can be easily distinguished from those bands where wave disturbances are very small compared to the noise.