Circulation and heat fluxes during the austral fall in George VI Sound, Antarctic Peninsula

Dorland, Ryan D.; Zhou, Meng

doi:10.1016/j.dsr2.2007.01.014

Cited by 11 publications

(5 citation statements)

References 26 publications

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“…There are no published estimates for the diffusivity in the deep layer (>500 m) of concern here, although studies attempting to estimate the heat fluxes across the pycnocline have found lower values, of the order of 10 −5 m 2 s −1 [ Howard et al , 2004], but it is unclear at this point whether this and other studies [ Smith and Klinck , 2002] are relevant for the mixing of LCDW. The problem of how large a buoyancy flux through the pycnocline (and by extension, laterally into the lower layer) and how large are the necessary diffusivities remain unresolved because of the lack of observations of at least two possible sources of mixing on the shelf: spatially localized mixing associated with the complicated bathymetry or nearshore processes [ Dorland and Zhou , 2008; Jenkins and Jacobs , 2008] or intermittently high mixing associated with strong storms. More detailed observations of the mixing processes on the shelf are required to resolve this issue.…”

Section: Discussionmentioning

confidence: 99%

On the characteristics of Circumpolar Deep Water intrusions to the west Antarctic Peninsula Continental Shelf

Moffat¹,

Owens²,

Beardsley³

2009

J. Geophys. Res.

119

159

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UCDW is found on the middle and outer shelf along Marguerite Trough, which connects the shelf break to Marguerite Bay, and at another location farther south. UCDW intrudes in the form of frequent (four per month) and small horizontal scales (%4 km) warm eddy-like structures with maximum vertical scales of a few hundred meters. However, no evidence of UCDW intrusions was found in Marguerite Bay. LCDW was found in several deep depressions connected to the shelf break, including Marguerite Trough, forming a tongue of relatively dense water 95 m thick (on average) that reaches into Marguerite Bay through Marguerite Trough. A steady advective-diffusive balance for the LCDW intrusion is used to make an estimation of the average upwelling rate and diffusivity in the deep layer within Marguerite Trough, which suggest the LCDW layer is renewed approximately every six weeks.

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Section: Discussionmentioning

confidence: 99%

On the characteristics of Circumpolar Deep Water intrusions to the west Antarctic Peninsula Continental Shelf

Moffat¹,

Owens²,

Beardsley³

2009

J. Geophys. Res.

119

159

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“…Meltwater fluxes are discharged from George VI Ice Shelf primarily into George VI Sound, which then mixes with southern Marguerite Bay waters (Jenkins and Jacobs, 2008). Marguerite Bay surface waters intrude into northern George VI Sound in the east, exiting to the west, with strong vertical mixing (upwelling and downwelling) in this region (Dorland and Zhou, 2008). Thus, subglacial water and processes occurring within the cavity may all contribute to the Fe enrichment on the +100 line, analogously to processes likely occurring near Pine Island Glacier and the Dotson ice shelves in the Amundsen Sea (Gerringa et al, 2012;Sherrell et al, 2015).…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Controls on dissolved and particulate iron distributions in surface waters of the Western Antarctic Peninsula shelf

et al. 2017

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The Western Antarctic Peninsula (WAP) displays high but variable productivity and is also undergoing rapid change. Long-term studies of phytoplankton communities and primary production have suggested transient limitation by the micronutrient iron (Fe), but to date no data have been available to test this hypothesis. Here, we present the first spatially extensive, multi-year measurements of dissolved and particulate trace metals in surface waters to investigate the key sources and sinks of Fe in the central WAP shelf. Surface samples of dissolved and particulate metals were collected throughout the 700 x 200 km grid of the Palmer Long-Term Ecological Research program in three consecutive austral summers (2010-2012). Iron concentrations varied widely. Both dissolved and particulate Fe were high in coastal waters (up to 8 nmol kg-1 and 42 nmol kg-1 , respectively). In contrast, very low Fe concentrations (< 0.1 nmol kg-1) were widespread in mid-to outer-shelf surface waters, especially in the northern half of the sampling grid, suggesting possible Fe limitation of primary production on the shelf. Sea ice and dust inputs of Fe were minor, although their relative importance increased with distance from shore due to the larger near-shore sources. Sedimentary inputs were inferred from manganese distributions; these were more significant in the northern portion of the grid, and showed interannual variation in intensity. Overall, the interannual distribution of Fe was most closely correlated to that of meteoric water (glacial melt and precipitation). Although the Fe concentrations and relative contributions of dissolved and particulate Fe attributed to meltwater were variable throughout the sampling region, increasing glacial meltwater flux can be expected to increase the delivery of Fe to surface waters of the coastal WAP in the future.

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“…Those authors identified the APCC in oceanographic moorings along the coast of Adelaide Island north of Marguerite Bay and concluded that the APCC is a seasonal (summer/fall) current that is driven by summer freshwater input from melting land ice and sea ice, combined with coastal downwelling associated with the generally southward wind stress along the coast [see also Hyatt et al , 2011]. The cooled water near 180 m depth around WIS may also contain a significant component of meltwater from the WIS and GVIIS bases [ Dorland and Zhou , 2008; Jenkins and Jacobs , 2008]. We expect the contribution to ocean cooling of basal melt from WIS and GVIIS to be most pronounced in the upper ocean as the ice‐shelf‐modified water is fresher (and, therefore, also lighter) than the source water.…”

Section: Environmental Settingmentioning

confidence: 99%

Oceanic controls on the mass balance of Wilkins Ice Shelf, Antarctica

et al. 2012

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[1] Several Antarctic Peninsula (AP) ice shelves have lost significant fractions of their volume over the past decades, coincident with rapid regional climate change. Wilkins Ice Shelf (WIS), on the western side of the AP, is the most recent, experiencing a sequence of large calving events in 2008 and 2009. We analyze the mass balance for WIS for the period 1992À2008 and find that the averaged rate of ice-shelf thinning was $0.8 m a

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Circulation and heat fluxes during the austral fall in George VI Sound, Antarctic Peninsula

Cited by 11 publications

References 26 publications

On the characteristics of Circumpolar Deep Water intrusions to the west Antarctic Peninsula Continental Shelf

On the characteristics of Circumpolar Deep Water intrusions to the west Antarctic Peninsula Continental Shelf

Controls on dissolved and particulate iron distributions in surface waters of the Western Antarctic Peninsula shelf

Oceanic controls on the mass balance of Wilkins Ice Shelf, Antarctica

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