Results of the research cruises of FRV 'Walther Herwig' to South America. LXXV: trans-Atlantic oceanographic measurements during South America Expeditions 1966-1976 of the Institute of Sea Fisheries, Hamburg, Germany

摘要

During the 1960s, with the new research platform FRV 'Walther Herwig' being available for long-distance exploratory fishery and ichthyology research, the Institute of Sea Fisheries started a series of South America Expeditions. During these expeditions large-scale oceanographic sections were performed which cross major oceanic surface current systems between 40pN and 40pS. By means of historic oceanographic data, as available through the World Data Centre A, Washington, the thermohaline situation along these sections is presented and described in relation to large-scale oceanic features like the North Atlantic Subpolar Gyre System, the northern Subtropical Gyre, the Atlantic Equatorial Current System, the southern Subtropical Gyre, the Brazil Current and the Malvinas Current System. Data obtained during the 1970s reveal large-scale oceanographic properties within the Subtropical Convergence belt at 40pS, between South America and South Africa. Based on these data, an analysis on the baroclinic current velocities of the upper 1000 m is presented. This analysis documents the deep reaching influence of the two boundary currents in this region, the Brazil Current system in the west, and the Agulhas/Benguela Current system in the east of the transect along 40pS. Also designed as large-scale ichthyology transects, the oceanographic observations performed during leg I of the Antarctic Expedition of the Federal Republic of Germany during 1975/1976 along 50pW and 40pW, reveal thermal properties across the Subtropical Convergence, in the sub-Antarctic surface waters and in Antarctic surface waters.