Wet and Dry Conditions and Pressure Anomaly Fields over South Africa and the Adjacent Oceans, 1963–79

Abstract

Circulation anomaly fields for wet and dry spells on monthly, seasonal and near-decadal scales are presented to show that at all these scales, both at the surface and at 500 mb, wet conditions are associated with negative anomalies of geopotential height over the continent and positive anomalies over the oceans to the southwest and south, and vice versa during dry spells. The changes in the pressure anomaly fields are shown to produce distinctive adjustments in the atmospheric fields of motion responsible for rain-producing conditions.