Copernicus Ocean State Report, issue 6

The 6th issue of the Copernicus OSR incorporates a large range of topics for the blue, white and green ocean for all European regional seas, and the global ocean over 1993–2020 with a special focus on 2020

Karadeniz Devrilme Sirkülasyone ve Değişim Göstergesi

The Black Sea (BS) is the largest deep estuarine basin in the world. Its meridional overturning circulation (BS-MOC) is here described for the first time: in particular, the BS-MOC interannual variability in both depth and density space has been computed using a state-of-the-art ocean reanalysis provided in the framework of the Copernicus Marine Service for the Black Sea of 28 year-period (1993–2020) for the definition of a new climate index.The mean meridional stream function defined for theupper 150 m in the depth space reveals an anticlock-wise cell in the southern part of the Black Sea comingfrom the injection of the Mediterranean watersthrough the Bosphorus Strait into the Black Sea anda clockwise cell in the northern part of the Black Seaas a manifestation of the Cold Intermediate Layer(CIL). The new index is then defined as maximumoverturning circulation in density space between22.45 and 23.85 kg m−3 . For the overall period, theBS-MOC index weakened between 1993 and 2010from 0.13 Sv down to 0.07 Sv, then it recovered andhas equilibrated around 0.1 Sv. Additionally, it showsa very strong correlation with the CIL from observational data, supporting the concept of using such an indicator to understand and monitor the water mass formation in the Black Sea basin.</p