A DESCRIPTION OF INTERANNUAL RAINFALL VARIANCE OVER SPACE AND TIME FOR SOUTH AFRICA: 1921–1975

Abstract

The interannual variability in rainfall over South Africa is shown to be composed of a number of uncorrelated components that are spatially dependent. There is a little evidence to support the view that interannual variability in rainfall has been increasing over the last twenty to thirty years. For the most part its temporal variation appears to be random. There seems to be little doubt, however, that a biennial oscillation is present in one of the uncorrelated components associated with the interannual variability in rainfall over South Africa. The period covered by the investigation is from 1921 to 1975 inclusive.