INTERANNUAL WIND VARIABILITY ON THE SOUTH AND EAST COASTS OF SOUTH-AFRICA

An analysis of 38 years of wind data from three sites along the South African east and south coasts is made to determine interannual variability. Different period bands are investigated, and it is found that the northernmost site (Durban, at about 30-degrees-S) differs markedly from the two southern sites (Port Elizabeth and Cape Town, at about 34-degrees-S). At the latter sites interannual trends exist in the yearly averaged wind directions, while for Port Elizabeth the principal axis orientations including winds lying within the ''weather band'' also show such a trend. It appears that a major readjustment occurred at the two southern sites during the very strong El Nino Southern Oscillation (ENSO) event in 1982/1983, with abrupt changes of up to 30-degrees in the wind directions being registered. On the other hand, there are no clearly identifiable trends in the wind speeds, and longer time series will be needed to establish correlations with weaker ENSO events.