Ocean circulation studies in the vicinity of Southern Africa: Preliminary results using FGGE drifters and remote sensing

Kinematics of the upwelling front off southern Africa

“…An appropriate image of such features for 8 June 1986 is presented in Figure 9. On this occasion a relic Agulhas Current retroflection lay far to the west of its average position (Lutjeharms and Van Ballegooyen 1987) with a number of warm filaments being advected from the general area of the Agulhas Current and the Agulhas Bank into the South-East Atlantic Ocean and along the upwelling front, in the manner previously described by Lutjeharms and Valentine (1981). On the Agulhas Bank, directly south of Africa, there is an extensive area of cold water, presumably upwelled, reminiscent of that reported by Walker (1986).…”

“…Such a jet has been described by Bang and Andrews (1974) off the Cape Peninsula. The possibility that this front may at times be dynamically unstable to small perturbations and that such instability may be enhanced by the ad vection of warm Agulhas Water adjacent to the upwelling front has been noted by Lutjeharms and Valentine (1981). The drift course of Agulhas filaments into the region may therefore be an important factor in initiating frontal breakdown, particularly in the southern reaches of the upwelling belt.…”

“…Recent]y a number of comprehensive and instructive overviews have ably summarized present knowledge on the area (Nelson andHutchings 1983, Shannon 1985, Chapman and Shannon ]985). A comprehensive bibliography of publications on the physical oceanology of the area has also been published (Lutjeharms et al 1981). The large-scale features of the upwelling regime are fairly well documented (see Fig.…”