The Wavenumber–Frequency Spectra of the 200 mb Wind Field in the Tropics

Abstract

The wavenumber?frequency spectra of the 200 mb wind field from 28.7°N to 28.7°S were examined for the 128?day period from mid-May to mid-September of 1970 and 1971. Evidence was presented that supported the existence of Rossby and mixed Rossby?gravity waves. Westward?propagating waves, with periods of about 10 days and wavenumber 10, centered at about 24°N were also observed. These waves appear to he associated with the tropical upper troughs. There were indications of equatorward transfers of energy from the mid-latitudes at periods of 9?10 and about 5 days.