A higher salinity (18.5 PSU) indicates
more intense mixing with the lower layer of Mediterranean water. On the other hand, a lower salinity (17.5 PSU) indicates mixing with coastal waters originating from the north-west Black Sea. In June and Roxadustat cost July, when CIW is advected to the region, the minimum temperature of (CIW)8 slowly decreases and the salinity at the minimum temperature depth increases. A thicker (CIW)8 with the minimum temperature is observed in the region during those months when there are no anticyclonic eddies. (CIW)8 was studied at two stations – B7 and B2 – in the Strait of Istanbul in 1999 (Figure 1), station B7 being chosen because of its location in the middle of the strait close to the channel contraction, and station B2 in the southern exit of the strait. The temperature, salinity profiles and T-S diagrams (Figure 4) at station B7 indicate that the depth of the interface varies in the range of 30–45 m. The upper layer temperature is between 6.2 and 25.1 ° C and its salinity changes between 15 and 23 PSU. The lower layer temperature is 14.2–15.8 °C and the salinity 36.5–37.8 PSU. The Mediterranean water layer is more saline and thicker at station B7 than at station K0. The salinity of the upper layer is also slightly higher than at station K0. For example, the salinity of the upper layer increases from 14.6 PSU at station K0 to 15.4 PSU at station B7 in July 1999 when Danube-influenced
water is observed in the Black Sea Alpelisib Pregnenolone exit of the strait. The upper layer salinity is almost 23 PSU in November and December 1999 due to an Orkoz event. During this event, strong south-westerly winds oppose the surface flow in the strait and cause the upper layer of the Sea of Marmara to fill the strait (Latif et al. 1991). Cold water is observed at station B7 only in June, July and August 1999, but this is not the original (CIW)8, as the minimum temperature of this cold water is ∼ 11 °C in June 1999. The reason for the increase in temperature of the cold water is mixing with the warm surrounding
waters along the strait. As can be seen from the T-S diagrams (Figure 4), the upper and lower layers at station B7 mix with each other because of entrainment along the strait (Oğuz et al. 1990). As a result of this mixing, the salinity and temperature of the cold water also increase, and it becomes located partly within the halocline. The temperature, salinity profiles and T-S diagrams at station B2 in 1999 indicate that the interface is observed between 20 m and 35 m depth. The upper layer temperature shows seasonal variations in the range from 6.5 to 24.8 °C, and its salinity changes in the 15.5–23 PSU range. The lower layer temperature ranges from 14.5 to 16 °C, its salinity from 36.7 to 38.1 PSU. The cold layer is found at station B2 only in June and August 1999, and its minimum temperature is slightly less than 14 °C during both months.