Combining physical and geochemical methods to investigate lower halocline water formation and modification along the Siberian continental slope

• Main Authors: M. B. Alkire, I. Polyakov, R. Rember, A. Pnyushkov, V. Ivanov, I. Ashik
• Format: Article
• Language: English
• Published: Copernicus Publications 2017-11-01
• Series: Ocean Science
• Online Access: https://www.ocean-sci.net/13/983/2017/os-13-983-2017.pdf

A series of cross-slope transects were occupied in 2013 and 2015 that extended eastward from St. Anna Trough to the Lomonosov Ridge. High-resolution physical and chemical observations collected along these transects revealed fronts in the potential temperature and the stable oxygen isotopic ratio (<i>δ</i>¹⁸O) that were observed north of Severnaya Zemlya (SZ). Using linear regressions, we describe mixing regimes on either side of the front that characterize a transition from a seasonal halocline to a permanent halocline. This transition describes the formation of lower halocline water (LHW) and the cold halocline layer via a mechanism that has been previously postulated by Rudels et al. (1996). Initial freshening of Atlantic Water (AW) by sea-ice meltwater occurs west of SZ, whereas higher influences of meteoric water and brine result in a transition to a separate mixing regime that alters LHW through mixing with overlying waters and shifts the characteristic temperature–salinity bend from higher (34.4  ≤  <i>S</i>  ≤  34.5) toward lower (34.2  ≤  <i>S</i>  ≤  34.3) salinities. These mixing regimes appear to have been robust since at least 2000.