Wavelet Analysis of the Convectively Coupled Equatorial Waves in the Wavenumber–Frequency Domain

Abstract

Wavelet analysis is performed on 31 yr (1975?2007, except 1978 and 1979) of daily outgoing longwave radiation data in the global equatorial region (15°S?15°N). Power spectra in the zonal wavenumber?frequency domain are obtained. With different scales and bandwidths than in previous Fourier-based analysis, peaks of variances that are associated with the various convectively coupled waves are found. Further, possibly because of the ability to resolve shorter waves that have limited zonal extent, significant variances are also found at tropical depression?type scales. However, waves of zonal wavenumber zero cannot be explicitly analyzed.