Radionuclides : a tool for oceanography

These results relate to the Topogulf cruise during summer 1983. The sampled area is located near the Azores islands on both sides of the mid-Atlantic ridge. The tritium content of the surface waters reveals a strong front along the Azores current. At depth, the spatial distribution of tritium is studied along isopycnals. In the thermocline, it is essentially the anticyclonic gyre which is responsible for the Northeast - Southwest gradient in tritium concentration. Some information about the "age" of the water masses is given by the use of both tritium and helium-3. In this way some areas where ventilation processes are active are identified. At middepth, a strong contrast exists between the young waters originating from the Labrador Sea and the more stagnant waters in the south east of the sampled area. (Résumé d'auteur