Analysis of rainfall variability in the northeastern region of South Africa

The mean monthly and annual rainfall series (1930–1977) for 30×30 blocks in the eastern Transvaal-Swaziland region ara analyzed. These series show temporal and spatial characteristics in the regional precipitation regime. Significance is attributed to oscillatory forcings with quasi-periodicities of about 16–20 years and 13–14 months that operate throughout the area. Oscillations near the quasi-biennial cycle are also observed but with less significance.