Аннотация:The structure and dynamics of different water masses in the Tropical Atlantic is investigated using the results of instrumental measurements. The main attention is focused on the Vema fracture zone and the northern part of the WOCE A15 section. In the Vema Fracture zone an intradiurnal variability of hydrological parameters was observed. We also assess the long-term variability of hydrological parameters along the WOCE A15 section.