Marine Ice Beneath Filchner Ice Shelf: Evidence from a Multi-Disciplinary Approach

Grosfeld, Klaus; Hellmer, Hartmut; Jonas, M.; Sandhäger, H.; Schulte, Mona; Vaughan, David G.

doi:10.1029/ar075p0319

Cited by 26 publications

(9 citation statements)

References 52 publications

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“…Two additional hotspots of marine ice formation (at rates of 0.5–1.0ma –1 ) are associated with the outflow of ice-shelf water (ISW) on the western sides of the Filchner and Ronne Troughs. For the Filchner Trough, the outflow of ISW and the formation of marine ice are consistent with the sub-ice flow pattern inferred by Nicholls and others (2001) and the glaciological findings of Grosfeld and others (1998), Joughin and Padman (2003) and Lambrecht and others (2007). For the Ronne Trough, evidence for marine ice formation exists for a narrow band along the coast (Nicholls and others, 2004).…”

Section: Resultssupporting

confidence: 77%

Ice-shelf basal melting in a global finite-element sea-ice/ice-shelf/ocean model

Timmermann¹,

Wang²,

Hellmer³

2012

Ann. Glaciol.

126

130

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ABSTRACT. The Finite Element Sea ice Ocean Model (FESOM) has been augmented by an ice-shelf component with a three-equation system for diagnostic computation of boundary layer temperature and salinity. Ice shelf geometry and global ocean bathymetry have been derived from the RTopo-1 dataset. A global domain with a triangular mesh and a hybrid vertical coordinate is used. To evaluate sub-ice shelf circulation and melt rates for presentday climate, the model is forced with NCEP reanalysis data. Basal mass fluxes are mostly realistic with maximum melt rates in the deepest parts near the grounding lines and marine ice formation in the northern sectors of Ross Ice Shelf and Filchner-Ronne Ice Shelf. Total basal mass loss for the ten largest ice shelves reflects the importance of the Amundsen Sea ice shelves; Getz Ice Shelf is shown to be a major melt water contributor to the Southern Ocean. Despite their modest melt rates, the "cold water' ice shelves in the Weddell Sea are still substantial sinks of continental ice in Antarctica. Discrepancies between the model and observations can partly be attributed to deficiencies in the forcing data or to (sometimes unavoidable) smoothing of ice shelf and bottom topographies.

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Section: Resultssupporting

confidence: 77%

Ice-shelf basal melting in a global finite-element sea-ice/ice-shelf/ocean model

Timmermann¹,

Wang²,

Hellmer³

2012

Ann. Glaciol.

126

130

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“…Refreezing fractions of about 0.8% to 2.7% (FNE3, red squares vs. solid magenta line in Figure ) would produce the observed Ne/salinity relations. FNE3 is the borehole closest to an area of the northern FIS where extensive basal freezing is known to occur (Grosfeld et al, ; Rignot et al, ).…”

Section: Resultsmentioning

confidence: 99%

Basal Melt and Freezing Rates From First Noble Gas Samples Beneath an Ice Shelf

Huhn

Hattermann

Davis

et al. 2018

Geophysical Research Letters

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A climatically induced acceleration in ocean‐driven melting of Antarctic ice shelves would have consequences for both the discharge of continental ice into the ocean and thus global sea level, and for the formation of Antarctic Bottom Water and the oceanic meridional overturning circulation. Using a novel gas‐tight in situ water sampler, noble gas samples have been collected from six locations beneath the Filchner Ice Shelf, the first such samples from beneath an Antarctic ice shelf. Helium and neon are uniquely suited as tracers of glacial meltwater in the ocean. Basal meltwater fractions range from 3.6% near the ice shelf base to 0.5% near the sea floor, with distinct regional differences. We estimate an average basal melt rate for the Filchner‐Ronne Ice Shelf of 177 ± 95 Gt/year, independently confirming previous results. We calculate that up to 2.7% of the meltwater has been refrozen, and we identify a local source of crustal helium.

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“…Marine ice is thought to buffer interactions between ice shelf and ocean [ Eicken and Lange , ], and to provide a stabilizing influence on ice shelves by healing rifts [ Khazendar and Jenkins , ], smoothing basal regions that could be expected to be heavily crevassed [ Smedsrud and Jenkins , ], and allowing ice shelves to deform rather than fail in response to stress [ Holland et al ., ]. Marine ice makes up significant volumes of the Filchner [ Grosfeld et al ., ], Ronne [ Engelhardt and Determann , ], Amery [ Craven et al ., , ; Fricker et al ., ], Ross [ Neal , ; Rignot et al ., ], McMurdo [ McCrae , ], and Larsen C Ice Shelves [ Holland et al ., ] and could be expected to exert similar or greater drag on the ocean boundary layer to that observed in this study.…”

Section: Discussionmentioning

confidence: 99%

Observations of amplified roughness from crystal accretion in the sub‐ice ocean boundary layer

Robinson

Stevens

McPhee

2017

Geophysical Research Letters

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Ice crystal accretion on the underside of sea ice and ice shelves, a signature of pressure‐induced supercooling, has the potential to alter the energy balance in the ocean boundary layer through enhanced hydrodynamic roughness. Here we present estimates of crystal‐driven ocean boundary layer roughness in supercooled water beneath sea ice adjacent to the McMurdo/Ross Ice Shelf. Data were collected from four sites in McMurdo Sound, Antarctica, between 2007 and 2015, and represent a range of ice shelf‐affected conditions. The results show that drag of the rough ice underside in the presence of platelets is 6–30 times larger than typical levels homogeneously applied in ice‐ocean interaction models. The crystal‐enhanced drag promotes increased entrainment into the boundary layer from the upper ocean, which has the potential to affect ice shelf evolution and sea ice growth through enhanced turbulent exchange of heat and momentum.

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Marine Ice Beneath Filchner Ice Shelf: Evidence from a Multi-Disciplinary Approach

Cited by 26 publications

References 52 publications

Ice-shelf basal melting in a global finite-element sea-ice/ice-shelf/ocean model

Ice-shelf basal melting in a global finite-element sea-ice/ice-shelf/ocean model

Basal Melt and Freezing Rates From First Noble Gas Samples Beneath an Ice Shelf

Observations of amplified roughness from crystal accretion in the sub‐ice ocean boundary layer

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