Henry Melson Stommel : from pionner to clasic

[EN] Stommel has been the most important physicist oceanographer of the second half of the XX century. Builder, to a great extent, of the present Dynamical Oceanography. He contributed to the transformation of the Oceanography from a sort of appendix of the studies of the Atmosphere to a new specialty of Geophysics. After graduating in Astronomy in Yale in 1942 he started his research participating in the WWII effort, collaborating together with many other future oceanographers, in support of the USA Navy. Research that was carried out in the Woods Hole Oceanographic Institution (WHOI). Between 1959 and 1978 he was professor of oceanography in Harvard U. first, and later in the Massachusetts Institute of Technology, returning to WHOI where he stayed until his death. Stommel established important and fundamental theories on the ocean global circulation and studied many other oceanographic phenomena. This theoretical activity he combined with not a less important observational one. He received many awards and hhonors, including the Craadford prize, equivalent to the Nobel in Geosciences.

Distribution of water masses and diapycnal mixing in the Cape Verde Frontal Zone

[EN]The Cape Verde Frontal Zone separates North and South Atlantic Central Waters in the eastern North Atlantic Subtropical Gyre. CTD-O2 and shipboard ADCP data from three hydrographic sections carried out in September 2003 are used to study the structure of the front. Results show the relation between spatial variations of water masses and currents, demonstrating the importance of advection in the distribution of water masses. Diapycnal diffusivities due to double diffusion and vertical shear instabilities are also estimated. Existence of competition between the two processes through the water column is shown. Depth-averaged diffusivities suggest that salt fingering dominates diapycnal mixing, except areas of purest South Atlantic Central Water. Here, double diffusion processes are weak and, consequently, shear of the flow is the main process. Results also show that strong mixing induced by vertical shear is associated with a large intrusion found near the front.