High Waves in the Benguela Current

Abstract

Analysis of merchant ship observations reveals a sharp ridge of high wave frequency along the axis of the Benguela Current, nearly coincident with the major shipping lane in that area. The authors could find no other reference to this wave regime in the literature. The majority of these waves are found to be southerly or southeasterly seas reinforced by swells of similar origin and direction. The steady winds within the stable subsiding air on the eastern edge of the semi-permanent subtropical South Atlantic Oceanic high pressure area are channeled to the northwest by the South African land mass, forming the driving mechanism that generates the waves. The thermal low over the continent further reinforces this regime, as does coastal upwelling. Resultant sharp local anomalies in air temperature, cloud cover and other elements are also present.