Abstract
Spectral analysis of long time series of three-hourly barometric observations at three Pacific Island stations was performed. In each case there was evidence for a peak in power near periods of about 33 hours. It appears that this oscillation is reasonably coherent over the roughly 30°longitude separation of the stations. Following Matsuno (1980) this "33 hour wave" is tentatively identified with the gravest, zonal wavenumber one normal mode Kelvin wave. The present analysis makes possible the first determination of the surface pressure amplitude of this oscillation; this was found to be roughly one-fifth that of the more familiar "five day" Rossby normal mode in the tropics as estimated by Madden and Julian (1973).
