DENSE WATER FORMATION OVER THE SAMOTHRAKI AND LIMNOS PLATEAUS IN THE NORTH AEGEAN SEA (EASTERN MEDITERRANEAN-SEA)

The North Aegean Sea was visited from 27 February to March 3 1987, dur ing the late winter LIA-5-87 national cruise in the framework of the O pen Sea Oceanography Research Program of NCMR. CTD data were collected from 31 stations on board R.V. Aegaio. Strong (velocities up to 17 ms -1) and cold (approximately 2-degrees-C) northerlies, dominating durin g the week before the cruise, contributed to the cooling of the sea wa ters. A particularly low sea surface temperature (10.83-degrees-C) was observed in the north eastern most part of the north Aegean Sea. The distribution of the hydrological characteristics combined with a serie s of infrared images reveals the presence of thermohaline and density fronts both over the Samothraki and Limnos Plateaux, possibly generate d by the confluence of water masses of different characteristics, name ly brackish and cold Black Sea waters effluing from the Straits of Dar danelles, fresh waters from rivers outflowing along the northern Greek coasts and warm and saline waters of Levantine origin. A considerable amount of the latter waters shaped as tongues seem to be projected in termittently over the Samothraki Plateau. Additionally, the surface la yers are supplied with waters of Levantine characteristics upwelled fr om deeper layers within the dome of a cyclonic eddy. Moreover, waters of high densities (sigma(theta) up to 29.20) appear throughout the wat er column, white the highest values (sigma(theta) = 29.37) are detecte d in near bottom layers over the shelf areas. The newly formed, oxygen rich, dense waters tend to follow the isobaths and finally slide towa rds the deepest basins of the North Aegean Trough, in agreement with t he theoretical prediction of SMITH (1975, Deep-Sea Research, 22, 853-8 73) and KILLWORTH (1977, Deep-Sea Research, 25, 927-988).