Variation of the cold intermediate water in the Black Sea exit of the Strait of Istanbul (Bosphorus) and its transfer through the strait*

The cold intermediate water (CIW, T < 8 °C) entering the Strait of Istanbul and its variation along the strait have been studied by using monthly conductivity-temperature-depth (CTD) data sets collected during the period from 1996 to 2000. In the northern exit of the strait, CIW is located between the seasonal thermocline and Mediterranean water originating from the lower layer of the Sea of Marmara. The thickness of CIW decreases from April to October. In the Strait of Istanbul, CIW is observed as a layer of temperature < 14 °C. The thickness of this modified cold intermediate water flowing southwards with the upper layer decreases, while its temperature increases along the strait due to mixing with adjacent water. In the southern exit of the strait, the modified cold intermediate water is observed during the period from May to October. If CIW exists in the Black Sea exit region of the strait, modified cold water is found in the Marmara exit region during the same period. The distribution of CIW in the Strait of Istanbul contributes to our understanding of the dynamics of the strait, especially in the summer months.