Spatiotemporal Structure and Variability of Thermohaline Parameters in the Intermediate Water Layer North of the Severnaya Zemlya Archipelago

Time series of water temperature and conductivity obtained over three years of continuous measurements at seven autonomous moored stations north of the Severnaya Zemlya archipelago located in the Arctic Basin of the Arctic Ocean were analyzed in combination with numerical modeling to investigate the spatiotemporal variability of temperature and salinity in the intermediate layer of Atlantic-origin waters. These waters propagate along the Eurasian continental slope within the Arctic Boundary Current (ABC). Within 85 km of the shelf edge, three distinct branches of Atlantic Water (AW) transport were identified, each characterized by a unique origin history of origin that shapes the variability of its thermohaline properties. The most energetic mode of temporal variability at all stations is associated with oscillations with a period of approximately 12 months. The amplitude of these oscillations decreases with increasing distance from the shelf edge, while their phase differs among the AW branches. Numerical modeling indicates that, in the study region, the typical phase–distance relationship observed in the western Nansen Basin is disrupted by the large-scale input of cold, freshened water through the St. Anna Trough.