The seasonal intrusion of relatively saline water on the shelf off northern and central Namibia

The movement of tropical, saline water onto the northern and central Namibian shelf in late summer and early autumn in the periods 1973–1974 and 1979–1986 is investigated. The strong intrusions in 1974, 1979, 1980(?), 1984 and 1986 appear related to positive thermal anomalies in the equatorial Atlantic and a southward deviation in the position of the Inter-Tropical Convergence Zone. A limited intrusion which occurred mainly subsurface in 1985 is compared with an extensive intrusion with both surface and subsurface expression in 1986. In 1984 a single, top-bottom intrusion was observed. This intrusion, which showed substantially lower concentrations of nutrients than in 1985 or 1986, has been termed a “Benguela Niño” on account of its resemblance to the Pacific phenomenon. © 1987 Taylor & Francis Group, LLC.