THE STRUCTURE AND EVOLUTION OF A MEDDY AND THE AZORES FRONTAL ZONE INAUTUMN, 1993

Analysis of the structure of hydrophysical fields and its vertical evo lution from the surface to a depth of 2-2.5 km was carried out on the basis of the measurements in autumn, 1993 in the study area (31 degree s-36 degrees N, 20 degrees-26 degrees W) in this part of the northeast Atlantic. A description of the Mediterranean water (MW) anticyclonic eddy which was found in the eastern part of the study area during a se ries of sequential hydrographic surveys is presented. The analysis of CTD and XBT measurements in the area west of the lens allows us to con clude that despite the narrowing of the Azores current width (from 60- 80 km to 50-60 km) the total transport of the current did not signific antly change during October and November. It is shown that the interme diate salinity maximum in the northern part of the study area formed b y the advection of the Mediterranean waters and destruction of the len ses is weakened across the section of the Azores frontal zone from nor th to south and displaced to greater depths together with the growth o f its thickness. The analysis of the historical data shows that the nu mber of lenses observed within the study area north of the Azores fron tal zone is twice as large as south of the zone. The salinity and loca l temperature maximums north of the Azores frontal zone may be related to accumulation of heat and salt due to the fact that the frontal zon e is not only the southern boundary of the penetration of the Mediterr anean waters in the Central Atlantic but is also a semi-transparent bo undary for the meddles.