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The temporal variability of the structure and two-dimensional phase propagation of the 40-50-day oscillation in tropical convection are diagnosed using complex empirical orthogonal function (CEOF) analysis of the 1974-1988 outgoing longwave radiation (OLR) data.Results from autoregressive spectrum analysis of the OLR time series indicate that apart from the well-known 40-50-day peak, there are other significant spectral peaks near 2C30 and 17 days. In much of the tropics, excluding the equatorial Indian and western Pacific Oceans, these higher frequency peaks appear to be distinct from the 4&50 day spectral peak.The dominant spatial mode of the 40-50-day oscillation consists of the well-known equatorial dipole and associated eastward propagation. Interactions between this mode and the extratropical 40-50-day oscillation are manifested through the propagation of convection anomalies to and from the tropics via the North Pacific, north-east Atlantic and north-east African subtropics. The sense of this propagation varies from season to season and year to year.Analysis of the oscillation during individual summers and winters and each of the

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