Transoceanic wave propagation links iceberg calving margins of Antarctica with storms in tropics and Northern Hemisphere

MacAyeal, Douglas R.; Okal, Emile A.; Aster, R. C.; Bassis, J. N.; Brunt, Kelly M.; Cathles, L. M.; Drucker, Robert; Fricker, H. A.; Kim, Young‐Jin; Martin, Seelye; Okal, Marianne; Sergienko, O. V.; Sponsler, Mark P.; Thom, Jonathan E.

doi:10.1029/2006gl027235

Cited by 117 publications

(121 citation statements)

References 22 publications

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“…The AIS has long been considered a stable ice shelf that is currently undergoing a natural advance-calve-advance cycle (Fricker et al, 2002). Observations of its mass balance (Wen et al, 2006(Wen et al, , 2008Yu et al, 2010) and model studies of the rift propagation process on its ice front (Larour et al, 2004;Bassis et al, 2005;MacAyeal et al, 2006) support that hypothesis. But the future state of the whole drainage system has large uncertainties under the influence of global warming and model studies can perhaps throw light on the future of the ice shelf and its adjacent glaciers.…”

Section: Introductionmentioning

confidence: 53%

Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

2014

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Abstract. The interaction between the climate system and the large polar ice sheet regions is a key process in global environmental change. We carried out dynamic ice simulations of one of the largest drainage systems in East Antarctica: the Lambert Glacier-Amery Ice Shelf system, with an adaptive mesh ice sheet model. The ice sheet model is driven by surface accumulation and basal melt rates computed by the FESOM (Finite-Element Sea-Ice Ocean Model) ocean model and the RACMO2 (Regional Atmospheric Climate Model) and LMDZ4 (Laboratoire de Météorologie Dynamique Zoom) atmosphere models. The change of ice thickness and velocity in the ice shelf is mainly influenced by the basal melt distribution, but, although the ice shelf thins in most of the simulations, there is little grounding line retreat. We find that the Lambert Glacier grounding line can retreat as much as 40 km if there is sufficient thinning of the ice shelf south of Clemence Massif, but the ocean model does not provide sufficiently high melt rates in that region. Overall, the increased accumulation computed by the atmosphere models outweighs ice stream acceleration so that the net contribution to sea level rise is negative.

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Section: Introductionmentioning

confidence: 53%

Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

2014

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“…However, the probability an iceberg will calve during a given interval of time can be described 30 by a probability distribution. This probability distribution depends on environmental conditions that can stimulate or inhibit the fracturing mechanism (MacAyeal et al, 2006). If the environmental parameters conditioning the probability of fracture can be determined, it would thus be possible to propose at least bulk fracturing laws that could be used in numerical models.…”

Section: Fragmentation Lawmentioning

confidence: 99%

Melting and fragmentation laws from the evolution of two large southern ocean icebergs

Bouhier

Tournadre

Rémy

et al. 2017

Preprint

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Abstract. The evolution of the thickness and area of two large southern ocean icebergs, having drifted in open water for more than a year, is estimated through the combined analysis of altimeter data and visible satellite images. Most of the iceberg modelling studies uses two main melting formulations that are compared with the observed thickness evolution of our two icebergs, to test their validity in case of large icebergs. The first formulation, based on a fluid dynamics approach, would tend to underestimate basal melt rates, so that using the second one (using a thermodynamic budget consideration) may be 5 more relevant. Fragmentation is, before melting, the major decay process of large icebergs, yet it is a complex and still poorly documented mechanism. A correlation analysis between the observed volume loss of our two icebergs and environmental parameters highlights those most likely to promote fragmentation. Consequently, a bulk model of fragmentation depending on ocean temperature and iceberg velocity is established and is shown to be able to reproduce well the observed volume variations.Finally, the size distribution of the calved pieces is estimated using both altimeter data and visible images and is found to be 10 consistent with previous studies as typical of brittle fragmentation processes. These results are valuable to account for a more realistic representation of the freshwater flux constrained by large icebergs in models.

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“…Several authors have suggested that calving from ice shelves and ice tongues may be triggered by flexural stresses induced by ocean swell (Holdsworth & Glynn 1978;MacAyeal et al 2006;Sergienko 2010), despite some contradictory observations that ice shelf rift propagation itself is not influenced by ocean swell (Bassis et al 2007(Bassis et al , 2008. To examine the role of ocean swell in generating transient stresses that contribute to failure of floating ice tongues, we estimated the magnitude of the horizontal stress induced in the ice following the order of magnitude estimation procedure described by Bassis et al (2007Bassis et al ( , 2008.…”

Section: (D) the Role Of Ocean Swell In Triggering Calving Events Fromentioning

confidence: 99%

Upper and lower limits on the stability of calving glaciers from the yield strength envelope of ice

2011

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Observations indicate that substantial changes in the dynamics of marine-terminating ice sheets and glaciers are tightly coupled to calving-induced changes in the terminus position. However, the calving process itself remains poorly understood and is not well parametrized in current numerical ice sheet models. In this study, we address this uncertainty by deriving plausible upper and lower limits for the maximum stable ice thickness at the calving face of marine-terminating glaciers, using two complementary models. The first model assumes that a combination of tensile and shear failure can render the ice cliff near the terminus unstable and/or enable pre-existing crevasses to intersect. A direct consequence of this model is that thick glaciers must terminate in deep water to stabilize the calving front, yielding a predicted maximum ice cliff height that increases with increasing water depth, consistent with observations culled from glaciers in West Greenland, Antarctica, Svalbard and Alaska. The second model considers an analogous lower limit derived by assuming that the ice is already fractured and fractures are lubricated by pore pressure. In this model, a floating ice tongue can only form when the ice entering the terminus region is relatively intact with few pre-existing, deeply penetrating crevasses.

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Transoceanic wave propagation links iceberg calving margins of Antarctica with storms in tropics and Northern Hemisphere

Cited by 117 publications

References 22 publications

Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

Modelling the response of the Lambert Glacier–Amery Ice Shelf system, East Antarctica, to uncertain climate forcing over the 21st and 22nd centuries

Melting and fragmentation laws from the evolution of two large southern ocean icebergs

Upper and lower limits on the stability of calving glaciers from the yield strength envelope of ice

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