Interaction of interannual and diurnal variations over equatorial Africa

This paper shows evidence of interannual variation of the local diurnal variability over equatorial Africa. The dry season of December-February over the equatorial African region of the eastern Democratic Republic of Congo (formerly Zaire) typically experiences wetter (drier) than normal seasonal anomalies during warm (cold) El Nino-Southern Oscillation (ENSO) events. This study finds that from the additive influence or phase locking of the seasonal cycle, the interannual signal from ENSO, and the local diurnal cycle, there is a tendency for local amplification of the remote ENSO signal over this region of equatorial Africa. This additive influence of the three temporal scales over the equatorial African region is established from the analysis of a multidecadal coupled ocean-atmosphere model integration that simulates the observed seasonal cycle and its interannual variations over equatorial Africa reasonably well.