Water-mass properties and circulation on the west Antarctic Peninsula Continental Shelf in Austral Fall and Winter 2001

Klinck, John M.; Hofmann, Eileen E.; Beardsley, Robert C.; Salihoğlu, Barıș; Howard, Susan L.

doi:10.1016/j.dsr2.2004.08.001

Cited by 168 publications

(177 citation statements)

References 27 publications

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“…Maximum depths of around 1600 m are found close to Alexander Island (Figure 2). The water mass structure over the WAP continental shelf and in Marguerite Bay is relatively straightforward, and has been described in detail previously (Hofmann et al, 1996;Klinck et al, 2004;Meredith et al, 2004;Smith et al, 1999). The oceanic source for all other water masses found here is Circumpolar Deep Water (CDW).…”

Section: Oceanographic Contextmentioning

confidence: 83%

See 1 more Smart Citation

Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: Results from δ18O

Meredith

Brandon

Wallace

et al. 2008

Deep Sea Research Part II: Topical Studies in Oceanography

109

126

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We investigate the seasonal variability in freshwater inputs to the Marguerite Bay region (Western Antarctic Peninsula) using a time series of oxygen isotopes in seawater from samples collected in the upper mixed layer of the ocean during 2002 and 2003. We find that meteoric water, mostly in the form of glacial ice melt, is the dominant freshwater source, accounting for up to 5% of the near-surface ocean during the austral summer. Sea ice melt accounts for a much smaller percentage, even during the summer (maximum around 1%). The seasonality in meteoric water input to the ocean (around 2% of the near-surface ocean) is not dissimilar to that of sea ice melt (around 2% in 2002 and 1% in 2003), contradicting the assumption that sea ice processes dominate the seasonal evolution of the physical ocean environment close to the Antarctic continent. Three full-depth profiles of oxygen isotopes collected in successive Decembers (2001, 2002 and 2003) indicate that around 4 m of meteoric water is present in the water column at this time of year, and around 1 m of sea ice formed from this same water column. The predominance of glacial melt is significant, since it is known to be an important factor in the operation of the ecosystem, for example by providing a source of nutrients and modifying the physical environment to control the spatial extent and magnitude of phytoplankton blooms.The Western Antarctic Peninsula is undergoing a very rapid change in climate, with increasing ocean and air temperatures, retreating glaciers and increases in precipitation associated with changes in atmospheric circulation. As climate change continues, we expect meteoric water inputs to the adjacent ocean to rise further. Sea ice in this sector of the Antarctic has shown a climatic decrease, thus we expect a reduction in oceanic sea ice melt fractions if this change continues. Continued monitoring of the oceanic freshwater budget at the western Peninsula is 2 needed to track these changes as they occur, and to better understand their ecological consequences.

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Section: Oceanographic Contextmentioning

confidence: 83%

“…Circulation on the WAP shelf includes a coastal current that flows southwest along the west coast of Adelaide Island and into Marguerite Bay, then around the bay before exiting near Alexander Island Klinck et al, 2004;Moffat et al, 2007). Its pathway through Marguerite Bay is, however, difficult to trace (Moffat et al, 2007).…”

Section: Oceanographic Contextmentioning

confidence: 99%

Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: Results from δ18O

Meredith

Brandon

Wallace

et al. 2008

Deep Sea Research Part II: Topical Studies in Oceanography

109

126

View full text Add to dashboard Cite

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“…The existence of cyclonic, semi-enclosed gyres separating the northeastward flow at the shelf break and the southwestward flow of the APCC has been postulated, though the structural persistence of such features has not been resolved in detail. Further information is presented in Beardsley et al (2004); Klinck et al (2004); Savidge and Amft (2009) etc., though in general the temporal variability of ocean circulation at the WAP is relatively poorly constrained On interannual timescales, the major drivers of atmospheric variability at the WAP are the Southern Annular Mode (SAM) and the El Niño-Southern Oscillation (ENSO) phenomenon (Marshall et al, 2006;Meredith et al, 2008b;Stammerjohn et al, 2008b). SAM is characterized by meridional movements of atmospheric mass between a node over Antarctica and an annulus encircling the lower-latitude Southern Ocean .…”

Section: Water Masses Circulation and Variability At The Wapmentioning

confidence: 99%

“…It has also been shown that the delivery of heat to the WAP shelf via the intrusion of deep waters from the Antarctic Circumpolar Current (ACC) increased over similar timescales (Martinson, 2011a;Schmidtko et al, 2014). The ACC is the major oceanographic current system that inhabits the Southern Ocean; unlike other sectors, it lies immediately adjacent to the Antarctic shelf at the WAP, enabling the warm, saline waters from its mid-layers to intrude onto the shelf in relatively unmodified form (Klinck et al, 2004;Martinson et al, 2008).…”

Section: Introductionmentioning

confidence: 99%

Changing distributions of sea ice melt and meteoric water west of the Antarctic Peninsula

Meredith

Stammerjohn

Venables

et al. 2017

Deep Sea Research Part II: Topical Studies in Oceanography

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Changing distributions of sea ice melt and meteoric water west of the Antarctic Peninsula, Deep-Sea Research Part II, http://dx.doi.org/10.1016/j.dsr2.2016 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting galley proof before it is published in its final citable form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe Western Antarctic Peninsula has recently undergone rapid climatic warming, with associated decreases in sea ice extent and duration, and increases in precipitation and glacial discharge to the ocean. These shifts in the freshwater budget can have significant consequences on the functioning of the regional ecosystem, feedbacks on regional climate, and sea-level rise. Here we use shelf-wide oxygen isotope data from cruises in four consecutive Januaries (2011 to 2014) to distinguish the freshwater input from sea ice melt separately from that due to meteoric sources (precipitation plus glacial discharge). Sea ice melt distributions varied from minima in 2011 of around 0 % up to maxima in 2014 of around 4-5 %. Meteoric water contribution to the marine environment is typically elevated inshore, due to local glacial discharge and orographic effects on precipitation, but this enhanced contribution was largely absent in January 2013 due to anomalously low 2 precipitation in the last quarter of 2012. Both sea ice melt and meteoric water changes are seen to be strongly influenced by changes in regional wind forcing associated with the Southern Annular Mode and the El Niño-Southern Oscillation phenomenon, which also impact on net sea ice motion as inferred from the isotope data. A near-coastal time series of isotope data collected from Rothera Research Station reproduces well the temporal pattern of changes in sea ice melt, but less well the meteoric water changes, due to local glacial inputs and precipitation effects.3

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“…The effects of seasonal sea ice-melt on the 18 O of seawater, and therefore salinity, are minimal ) but those of glacial ice-melt are considerably more significant as high latitude ice has very low 18 O, with values as low as −50‰ (Weiss et al 1979;Meredith et al 2008). The meltwater fraction that we assume for modern waters around James Ross Island may be a little overestimated because here warm water upwelling onto the shelf (Fahrbach et al 1995) is less significant than in Marguerite Bay, which is affected by upwelling of relatively warm Circumpolar Deep Water (CDW) (e.g., Klinck et al 2004). …”

Section: Weddell Seamentioning

confidence: 89%

Fossil proxies of near-shore sea surface temperatures and seasonality from the late Neogene Antarctic shelf

Clark

Williams

Hill

et al. 2013

Naturwissenschaften

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Water-mass properties and circulation on the west Antarctic Peninsula Continental Shelf in Austral Fall and Winter 2001

Cited by 168 publications

References 27 publications

Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: Results from δ18O

Variability in the freshwater balance of northern Marguerite Bay, Antarctic Peninsula: Results from δ18O

Changing distributions of sea ice melt and meteoric water west of the Antarctic Peninsula

Fossil proxies of near-shore sea surface temperatures and seasonality from the late Neogene Antarctic shelf

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