Water Mass Variability and Levantine Intermediate Water Formation in the Eastern Mediterranean Between 2015 and 2017

• Published in: Journal of geophysical research. Oceans 2021-02, Vol.126 (2), p.n/a
• Main Authors: Fach, Bettina A., Orek, Hasan, Yilmaz, Elif, Tezcan, Devrim, Salihoglu, Ilkay, Salihoglu, Baris, Latif, Mohammed Abdul
• Format: Article
• Language: English
• Subjects: Levantine Basin; Levantine Intermediate Water; water mass formation
• ISSN: 2169-9275; 2169-9291
• DOI: 10.1029/2020JC016472

The physical characteristics of water masses in the Cilician Basin were analyzed based on recent, comprehensive in‐situ data. Nine seasonal cruises from June 2015 to November 2017 were carried out in an area located in the north‐eastern Levantine Basin between the coasts of Turkey and Cyprus. In this little studied area, the structure of the water column, its seasonal variability, and water formation events are investigated. The extensive data set reveals that in summer Modified Atlantic Water (MAW) is observed at about 50 m depth. Saltier and warmer Levantine Intermediate Water (LIW) lies below the MAW between ∼100 and 250 m. During winter, the water column becomes mixed due to surface cooling and vertical convection, and displays uniform properties from the surface to about 200–300 m depths. The yearly cycle of a vertically uniform water column during winter and the appearance of LIW in the following period suggests that LIW is being formed in this region, which is confirmed through heat and buoyancy flux calculations. It is the first time LIW formation is reported in this area of the north‐eastern Levantine Basin and adds to the areas of LIW formation outside Rhodes Gyre. In the 2.5 years of the study, LIW salinity increased by 0.11 psu in 2017, while surface water salinity increased by 0.5 psu over the same period. The presence of meso‐scale eddies in the study area is observed throughout the year. The eddies are short‐lived, having a time span of a few months, during which they either change location or disappear. Plain Language Summary Variability of water mass properties in the Cilician Basin, located in the north‐eastern part of the Mediterranean Sea, was investigated during nine research cruises spanning 2.5 years. This was done measuring temperature, salinity, and oxygen of the water column at several locations in the region. The study describes the seasonal cycle of the water masses and it is shown for the first time that in winter cold, dense water is formed in this region that sinks to depths of 100–250 m. This is because water increases its density due to cooling and forms a water mass known as Levantine Intermediate Water. It is of importance to know where and how much of this water mass is formed, because it travels throughout the Mediterranean Sea and exits through the Strait of Gibraltar, where it influences the water masses and circulation in the Atlantic Ocean. The study also found that the salinity of that water mass increased by 0.11