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

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 (δ...

Full description

Bibliographic Details
Published in:Ocean Science
Main Authors: M. B. Alkire, I. Polyakov, R. Rember, A. Pnyushkov, V. Ivanov, I. Ashik
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2017
Subjects:
geo
Online Access:https://doi.org/10.5194/os-13-983-2017
https://www.ocean-sci.net/13/983/2017/os-13-983-2017.pdf
https://doaj.org/article/ca60093dc06b4d02b2acbf1d62ae7c11
Description
Summary: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 (δ18O) 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 ≤ S ≤ 34.5) toward lower (34.2 ≤ S ≤ 34.3) salinities. These mixing regimes appear to have been robust since at least 2000.