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Variability in high-salinity shelf water production in the Terra Nova Bay polynya, Antarctica

Authors :
Chung Yeon Hwang
Seung-Tae Yoon
Won Sang Lee
SungHyun Nam
Craig Stevens
Sukyoung Yun
Gwang Il Jang
Stefan Jendersie
Jiyeon Lee
Source :
Ocean Science, Vol 16, Pp 373-388 (2020)
Publication Year :
2020
Publisher :
Copernicus GmbH, 2020.

Abstract

Terra Nova Bay in Antarctica is a formation region for high-salinity shelf water (HSSW), which is a major source of Antarctic Bottom Water. Here, we analyze spatiotemporal salinity variability in Terra Nova Bay with implications for the local HSSW production. The salinity variations in the Drygalski Basin and eastern Terra Nova Bay near Crary Bank in the Ross Sea were investigated by analyzing hydrographic data from instrumented moorings, vessel-based profiles, and available wind and sea-ice products. Near-bed salinity in the eastern Terra Nova Bay (∼660 m) and Drygalski Basin (∼1200 m) increases each year beginning in September. Significant salinity increases (>0.04) were observed in 2016 and 2017, which is likely related to active HSSW formation. According to velocity data at identical depths, the salinity increase from September was primarily due to advection of the HSSW originating from the coastal region of the Nansen Ice Shelf. In addition, we show that HSSW can also be formed locally in the upper water column ( m) of the eastern Terra Nova Bay through convection supplied by brine from the surface, which is related to polynya development via winds and ice freezing. While the general consensus is that the salinity of the HSSW was decreasing from 1995 to the late 2000s in the region, the salinity has been increasing since 2016. In 2018, it returned to values comparable to those in the early 2000s.

Details

ISSN :
18120792
Volume :
16
Database :
OpenAIRE
Journal :
Ocean Science
Accession number :
edsair.doi.dedup.....312d54a94efb23c1cbceb9576ab42636
Full Text :
https://doi.org/10.5194/os-16-373-2020