From circumpolar deep water to the glacial meltwater plume on the eastern Amundsen Shelf

Nakayama, Yoshihiro; Schröder, Michael; Hellmer, Hartmut

doi:10.1016/j.dsr.2013.04.001

Cited by 76 publications

(105 citation statements)

References 37 publications

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“…Remote sensing data show that ice loss in this sector has increased greatly over the past 25 years through ice thinning and flow acceleration that is triggered by thinning of the floating ice shelves at rates between 3.9 and 5.3 m yr-1 (Rignot, 2008;Rignot et al, 2008;Rignot et al, 2014;Pritchard et al, 2009;Wingham et al, 2009). Integration of remote sensing data with oceanographic observations shows that this thinning results from enhanced basal melting driven by incursion of relatively warm Circumpolar Deep Water (CDW) onto the continental shelf (Jacobs et 25 al., 1996;Jacobs et al, 2011;Pritchard et al, 2012;Nakayama et al, 2013;Dutrieux et al, 2014a). Precise dating of changes in sediment cores recovered beneath PIG ice shelf indicates that the present phase of thinning and retreat was initiated in the 1940s (Smith et al, 2017), which is consistent with a hypothesis that CDW incursion increased at this time driven by wind stress changes associated with a large El Niño event between 1939-42 (Steig et al, 2012).…”

Section: Introductionsupporting

confidence: 71%

Bathymetric Controls on Calving Processes at Pine Island Glacier

Arndt¹,

Larter²,

Friedl³

et al. 2018

Preprint

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Abstract. Pine Island Glacier is the largest current Antarctic contributor to sea level rise. Its ice loss has substantially increased over the last 25 years through thinning, acceleration and grounding line retreat. However, the calving line positions of the 10 stabilizing ice shelf did not show any trend within the observational record (last 70 years) until calving in 2015 led to unprecedented retreat and changed alignment of the calving front. Bathymetric surveying revealed a ridge below the former ice shelf and two shallower highs to the north. Satellite imagery shows that ice contact on the ridge likely was lost in 2006 but was followed by intermittent contact resulting in back stress fluctuations on the ice shelf. Continuing ice shelf flow also led to occasional ice shelf contact with the northern bathymetric highs, which initiated rift formation that led to calving. The 15 observations show that bathymetry is an important factor in initiating calving events.

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Section: Introductionsupporting

confidence: 71%

Bathymetric Controls on Calving Processes at Pine Island Glacier

Arndt¹,

Larter²,

Friedl³

et al. 2018

Preprint

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“…We were able to repeat a quasimeridional section across the shelf to the east of Burke Island that had been occupied only once before (Jacobs et al, 1996). Our hope to reoccupy the zonal section collected by R/V Polarstern in 2010 (Nakayama et al, 2013) was thwarted by extensive sea ice over the northern Amundsen Sea shelf, but we were fortunate that low sea ice cover allowed sections to be undertaken across the front of Pine Island Glacier ice front (adding to a time series of such sections taken every few years) and around the front of the pack ice surrounding Thwaites Ice Shelf. The exciting data set will allow hydrographic section from the shelf edge to the Pine Island Ice Shelf (Figure 4).…”

Section: Seals As Oceanographic Recruits Provide New Perspectivesmentioning

confidence: 98%

“…The undercurrent follows the shelf break and may turn onto the shelf when it encounters crosscutting troughs . Once on the continental shelf, CDW is thought to follow the glacially carved bathymetric troughs to the ice shelves (Thoma et al, 2008;Jacobs et al, 2011;Nakayama et al, 2013).…”

mentioning

confidence: 99%

Between the Devil and the Deep Blue Sea: The Role of the Amundsen Sea Continental Shelf in Exchanges Between Ocean and Ice Shelves

Heywood¹,

Biddle²,

Boehme

et al. 2016

Oceanog.

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“…The relatively warm water of open ocean origin rarely reaches the southern Weddell Sea ice shelf fronts (Årthun et al 2012). This is in contrast to the Amundsen and Bellingshausen Seas, where derivatives of Circumpolar Deep Water (CDW) flush the continental shelf and reach the fringing ice shelf fronts with temperatures of over 18C (Jacobs et al 2011;Nakayama et al 2013). There, in the southeast Pacific Ocean, the onshore flow is supported by the close proximity of the southern flank of the Antarctic Circumpolar Current (ACC) to the continental shelf (Orsi et al 1995).…”

Section: Introductionmentioning

confidence: 99%

The Fate of the Southern Weddell Sea Continental Shelf in a Warming Climate

et al. 2017

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Warm water of open ocean origin on the continental shelf of the Amundsen and Bellingshausen Seas causes the highest basal melt rates reported for Antarctic ice shelves with severe consequences for the ice shelf/ice sheet dynamics. Ice shelves fringing the broad continental shelf in the Weddell and Ross Seas melt at rates orders of magnitude smaller. However, simulations using coupled ice-ocean models forced with the atmospheric output of the HadCM3 SRES-A1B scenario run (CO 2 concentration in the atmosphere reaches 700 ppmv by the year 2100 and stays at that level for an additional 100 years) show that the circulation in the southern Weddell Sea changes during the twenty-first century. Derivatives of Circumpolar Deep Water are directed southward underneath the Filchner-Ronne Ice Shelf, warming the cavity and dramatically increasing basal melting. To find out whether the open ocean will always continue to power the melting, the authors extend their simulations, applying twentieth-century atmospheric forcing, both alone and together with prescribed basal mass flux at the end of (or during) the SRES-A1B scenario run. The results identify a tipping point in the southern Weddell Sea: once warm water flushes the ice shelf cavity a positive meltwater feedback enhances the shelf circulation and the onshore transport of open ocean heat. The process is irreversible with a recurrence to twentieth-century atmospheric forcing and can only be halted through prescribing a return to twentieth-century basal melt rates. This finding might have strong implications for the stability of the Antarctic ice sheet.

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From circumpolar deep water to the glacial meltwater plume on the eastern Amundsen Shelf

Cited by 76 publications

References 37 publications

Bathymetric Controls on Calving Processes at Pine Island Glacier

Bathymetric Controls on Calving Processes at Pine Island Glacier

Between the Devil and the Deep Blue Sea: The Role of the Amundsen Sea Continental Shelf in Exchanges Between Ocean and Ice Shelves

The Fate of the Southern Weddell Sea Continental Shelf in a Warming Climate

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