scholarly journals Spatio-temporal variations in High-Salinity Shelf Water production in Terra Nova Bay polynya, Antarctica

2019 ◽  
Author(s):  
Seung-Tae Yoon ◽  
Won Sang Lee ◽  
Craig Stevens ◽  
Stefan Jendersie ◽  
SungHyun Nam ◽  
...  
Keyword(s):  
High Salinity ◽  
Ross Sea ◽  
Coastal Region ◽  
Deep Ocean ◽  
Temporal Variations ◽  
Shelf Water ◽  
Terra Nova Bay ◽  
Salinity Increase ◽  
Terra Nova ◽  
Spatio Temporal

Abstract. The formation of High-Salinity Shelf Water (HSSW), which is the major source of Antarctic bottom water (AABW), has been observed in Terra Nova Bay (TNB) in Antarctica. We believe a description of the spatio-temporal variation of salinity in TNB would help understand the production of HSSW in the region. Hence, the aim of this study is to investigate salinity variations in the Drygalski Basin (DB) and eastern TNB close to Crary Bank of the Ross Sea. For this, we use the moored and profiled hydrographic data, as well as available wind and sea-ice products. We found that deep-ocean salinity in the eastern TNB (~ 660 m) and DB (~ 1200 m) increases each year starting in September, and large amounts of salinity increase (> 0.04) were observed in 2016 and 2017. According to the velocity data observed at the same depths, the increases in salinity from September were due to the advection of HSSW from the coastal region of the Nansen ice shelf (NIS). The significant increases in salinity are related to the formation of active HSSW, evidence of which can be found from the HSSW properties obtained in February 2017 and March 2018. In addition, we show that HSSW can locally formed in the upper layer (

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

Ocean Science ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 373-388 ◽  
Author(s):  
Seung-Tae Yoon ◽  
Won Sang Lee ◽  
Craig Stevens ◽  
Stefan Jendersie ◽  
SungHyun Nam ◽  
...  
Keyword(s):  
High Salinity ◽  
Ross Sea ◽  
Coastal Region ◽  
Shelf Water ◽  
Antarctic Bottom Water ◽  
Ice Shelf ◽  
Terra Nova Bay ◽  
Salinity Variability ◽  
Salinity Increase ◽  
Terra Nova

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 (<300 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.

scholarly journals Potential Sources of Particulate Iron in Surface and Deep Waters of the Terra Nova Bay (Ross Sea, Antarctica)

Water ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3517
Author(s):  
Paola Rivaro ◽  
Francisco Ardini ◽  
Davide Vivado ◽  
Roberto Cabella ◽  
Pasquale Castagno ◽  
...  
Keyword(s):  
Trace Metals ◽  
Ross Sea ◽  
Shelf Water ◽  
Ice Shelf ◽  
Terra Nova Bay ◽  
Deep Waters ◽  
Suspended Particulate ◽  
Particulate Iron ◽  
Ice Shelf Water ◽  
Terra Nova

The distribution of particulate Fe (pFe), suspended particulate matter (SPM), and other particulate trace metals were investigated in Terra Nova Bay as part of CDW Effects on glaciaL mElting and on Bulk of Fe in the Western Ross sea (CELEBeR) and Plankton biodiversity and functioning of the Ross Sea ecosystems in a changing Southern Ocean (P-ROSE) projects. Variable concentrations of SPM (0.09–97 mg L−1), pFe (0.51–8.70 nM) and other trace metals were found in the Antarctic Surface waters (AASW) layer, where the addition of meltwater contributed to the pool with both lithogenic and biogenic forms. The deeper layer of the water column was occupied by High Salinity Shelf Water (HSSW) and Terra Nova Bay Ice Shelf Water (TISW) encompassing glacial water as confirmed by the lightest δ18O measured values. The concentration of pFe in TISW (11.7 ± 9.2 nM) was higher than in HSSW samples (5.55 ± 4.43 nM), suggesting that the drainage of material released from glaciers surrounding the area is relevant in terms of pFe contribution. Particulate Fe/Al and Mn/Al ratios were substantially in excess compared with the mean crustal ratios. Microscopic analyses confirmed that more labile Fe oxyhydroxides and authigenic MnO2 phases were present together with biogenic sinking material. Future expected increasing melt rates of these glaciers enlarge Fe input, thus having a greater role in supplying iron and counteracting the reductions in sea ice cover around Terra Nova Bay.

Trace metals distributions in coastal sea ice of Terra Nova Bay, Ross Sea, Antarctica

2005 ◽  
Vol 17 (2) ◽  
pp. 289-300 ◽  
Author(s):  
MARCO GROTTI ◽  
FRANCESCO SOGGIA ◽  
CARMELA IANNI ◽  
ROBERTO FRACHE
Keyword(s):  
Sea Ice ◽  
Ross Sea ◽  
Ice Cores ◽  
Temporal Variations ◽  
Metal Availability ◽  
Terra Nova Bay ◽  
Vertical Distributions ◽  
Coastal Sea ◽  
Terra Nova ◽  
Iron Manganese

In an attempt to clarify the release of trace elements from the seasonal coastal sea ice, samples were periodically collected in a nearshore station inside the Gerlache Inlet (Terra Nova Bay, Western Ross Sea), during the summer 2000/01 and analysed for dissolved and particulate cadmium, copper, iron, manganese and lead, as well as salinity, suspended particulate matter, nutrients and phytoplankton pigments. In order to provide insight on the metal association with the particles included in the sea ice, the metal solid speciation was also investigated. Both vertical distributions within the ice cores and temporal variations at the seawater interface were studied, in an effort to fully characterize the system and correlation among the considered parameters. Concentrations and speciation patterns clearly indicate metal incorporation within the annual sea ice due to resuspension of sediments, followed by release of particulate metals during melting as a primary process affecting trace metal availability in the Antarctic coastal waters.

scholarly journals Anthropogenic carbon distribution in the Ross Sea, Antarctica

2007 ◽  
Vol 19 (3) ◽  
pp. 395-407 ◽  
Author(s):  
S. Sandrini ◽  
N. Ait-Ameur ◽  
P. Rivaro ◽  
S. Massolo ◽  
F. Touratier ◽  
...  
Keyword(s):  
High Salinity ◽  
Ross Sea ◽  
Deep Ocean ◽  
Shelf Water ◽  
Ice Shelf ◽  
Carbon Export ◽  
Anthropogenic Carbon ◽  
Dense Water Formation ◽  
Ice Shelf Water ◽  
The Antarctic

AbstractThe Ross Sea is an area of dense water formation within the Southern Ocean, hence it potentially plays an important role for anthropogenic CO2 sequestration. In order to estimate the penetration of anthropogenic carbon in the Ross Sea from total inorganic carbon (TCO2) measurements carried out in 2002–03 Antarctic Italian Expedition, we applied two independent models. Anthropogenic carbon was present throughout the water column. The highest concentrations were associated with the recently ventilated shelf waters, namely High Salinity Shelf Water (HSSW) and Ice Shelf Water (ISW), due to their recent contact with the atmosphere. The lowest concentrations were observed for Circumpolar Deep Water (CDW), due to its relatively older ventilation age. This water mass intrudes onto the shelf in some parts of the Ross Sea and hence is observed in the sampled section, where it is recognizable for its low O2 and high TCO2 concentrations. The overflow of the dense High Salinity Shelf Water out of the continental slope was observed in the area off Cape Adare. Since this recently formed shelf water contributes to the formation of the Antarctic Bottom Water (AABW), this process represents a pathway for anthropogenic carbon export down to the deep ocean.

Katabatic wind propagation over the western Ross Sea observed using ERS-1 scatterometer data

1997 ◽  
Vol 9 (2) ◽  
pp. 221-226 ◽  
Author(s):  
Gareth J. Marshall ◽  
John Turner
Keyword(s):  
Ross Sea ◽  
Coastal Region ◽  
Open Water ◽  
Katabatic Wind ◽  
Wind Fields ◽  
Atmospheric Flow ◽  
Terra Nova Bay ◽  
Pressure Centre ◽  
Terra Nova ◽  
Western Ross Sea

Wind fields derived from ERS-1 scatterometer data, acquired over the open water present in the western Ross Sea during the summer season, are used to study the patterns of mesoscale atmospheric flow connected with surges of katabatic air from the Terra Nova Bay convergence zone, located in the coastal region of Victoria Land. These katabatic winds may turn northward but also southward, or divide into separate northward- and southward-turning components; the latter situation is illustrated by a detailed case study. Analysis of concurrent AWS data, suggests that the most likely mechanism for the observed southward turning is the existence of a highly-localised low pressure centre south of Terra Nova Bay. Comparison of multitemporal ERS-1 scatterometer wind fields with AWS wind measurements demonstrate that the satellite data are: (i) able to correctly portray changes in mesoscale circulation patterns, and (ii) suitable for the routine monitoring of winds over open water around the Antarctic coastline, despite a less than ideal temporal coverage.

scholarly journals Rebound of shelf water salinity in the Ross Sea

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Pasquale Castagno ◽  
Vincenzo Capozzi ◽  
Giacomo R. DiTullio ◽  
Pierpaolo Falco ◽  
Giannetta Fusco ◽  
...  
Keyword(s):  
Large Scale ◽  
Bottom Water ◽  
High Salinity ◽  
Ross Sea ◽  
Shelf Water ◽  
Antarctic Bottom Water ◽  
Sea Bottom ◽  
Salinity Increase ◽  
Interannual Fluctuations ◽  
Observational Record

AbstractAntarctic Bottom Water (AABW) supplies the lower limb of the global overturning circulation and ventilates the abyssal ocean. In recent decades, AABW has warmed, freshened and reduced in volume. Ross Sea Bottom Water (RSBW), the second largest source of AABW, has experienced the largest freshening. Here we use 23 years of summer measurements to document temporal variability in the salinity of the Ross Sea High Salinity Shelf Water (HSSW), a precursor to RSBW. HSSW salinity decreased between 1995 and 2014, consistent with freshening observed between 1958 and 2008. However, HSSW salinity rebounded sharply after 2014, with values in 2018 similar to those observed in the mid-late 1990s. Near-synchronous interannual fluctuations in salinity observed at five locations on the continental shelf suggest that upstream preconditioning and large-scale forcing influence HSSW salinity. The rate, magnitude and duration of the recent salinity increase are unusual in the context of the (sparse) observational record.

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