Water Masses in Upper and Middle North Atlantic Ocean East of Azores

During the "ANA" cruise in November 1988, Western North Atlantic Water (WNAW) was found linked to the Azores Current (AC) at 23° W, where according to various authors Eastern North Atlantic Water (ENAW) forms a boundary with WNAW east of the Mid-Atlantic Ridge (MAR). This boundary changes position during the year. The vein of Mediterranean Water (MW) moving towards the MAR seems to be connected with the AC, and restricts the penetration of ENAW of subpolar origin (ENAWP).A subsurface front has been found along 42° N, separating ENAW of subtropical origin (ENAWT) that moves northeastwards generating a cyclonic eddy that is confined between the lower limit of surface layer and approximately isopycnal 27.06, and modified ENAWP that moves southwards forming various anticyclonic eddies.