Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr

Cavitte, Marie G. P.; Parrenin, Frédéric; Ritz, Catherine; Young, D. A.; Liefferinge, Brice Van; Blankenship, D. D.; Frezzotti, Màssimo; Roberts, Jason L.

doi:10.5194/tc-12-1401-2018

Cited by 35 publications

(49 citation statements)

References 57 publications

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“…Eisen, 2008). Recent work in this area has been carried out on time-scales ranging from annual to centennial to millennial (Eisen and others, 2008; Medley and others, 2014; Nielsen and others, 2015; Grima and others, 2016; Karlsson and others, 2016; Koenig and others, 2016; Koutnik and others, 2016; MacGregor and others, 2016; Lewis and others, 2017; Cavitte and others, 2018; Karlsson and others, 2020; Montgomery and others, 2020). Efforts to automate layer tracing continue, which include methodologies that use seed points to initiate semi-automatic tracing routines as well as fully automatic schemes.…”

Section: Englacial Structurementioning

confidence: 99%

Five decades of radioglaciology

et al. 2020

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Radar sounding is a powerful geophysical approach for characterizing the subsurface conditions of terrestrial and planetary ice masses at local to global scales. As a result, a wide array of orbital, airborne, ground-based, and in situ instruments, platforms and data analysis approaches for radioglaciology have been developed, applied or proposed. Terrestrially, airborne radar sounding has been used in glaciology to observe ice thickness, basal topography and englacial layers for five decades. More recently, radar sounding data have also been exploited to estimate the extent and configuration of subglacial water, the geometry of subglacial bedforms and the subglacial and englacial thermal states of ice sheets. Planetary radar sounders have observed, or are planned to observe, the subsurfaces and near-surfaces of Mars, Earth's Moon, comets and the icy moons of Jupiter. In this review paper, and the thematic issue of the Annals of Glaciology on ‘Five decades of radioglaciology’ to which it belongs, we present recent advances in the fields of radar systems, missions, signal processing, data analysis, modeling and scientific interpretation. Our review presents progress in these fields since the last radio-glaciological Annals of Glaciology issue of 2014, the context of their history and future prospects.

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Section: Englacial Structurementioning

confidence: 99%

Five decades of radioglaciology

et al. 2020

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“…In this study, we consider two transient deglacial climate simulations, namely the TraCE-21ka and LOVECLIM DG ns deglacial experiments (Table 1). TraCE-21ka is a transient climate simulation of the last 22 000 years using the Community Climate System Model version 3 (CCSM3), a synchronously coupled GCM with atmosphere, ocean, land surface, and sea ice components and a dynamic global vegetation module (Collins et al, 2006;Liu et al, 2009;He, 2011). The transient forcings included evolving orbital forcing following Milankovitch theory (Genthon et al, 1987), greenhouse gas concentrations (CO 2 , CH 4 , N 2 O; Joos and Spahni, 2008), ice sheet and paleogeography changes based on the ICE-5G reconstruction (Peltier, 2004), and prescribed meltwater fluxes into the Atlantic, North Atlantic, and Southern Ocean (see He, 2011).…”

Section: Transient Climate Model Simulationsmentioning

confidence: 99%

Deglacial evolution of regional Antarctic climate and Southern Ocean conditions in transient climate simulations

et al. 2019

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Abstract. Constraining Antarctica's climate evolution since the end of the Last Glacial Maximum (∼18 ka) remains a key challenge, but is important for accurately projecting future changes in Antarctic ice sheet mass balance. Here we perform a spatial and temporal analysis of two transient deglacial climate simulations, one using a fully coupled GCM (TraCE-21ka) and one using an intermediate complexity model (LOVECLIM DGns), to determine regional differences in deglacial climate evolution and identify the main strengths and limitations of the models in terms of climate variables that impact ice sheet mass balance. The greatest continental surface warming is observed over the continental margins in both models, with strong correlations between surface albedo, sea ice coverage, and surface air temperature along the coasts, as well as regions with the greatest decrease in ice surface elevation in TraCE-21ka. Accumulation–temperature scaling relationships are fairly linear and constant in the continental interior, but exhibit higher variability in the early to mid-Holocene over coastal regions. Circum-Antarctic coastal ocean temperatures at grounding line depths are highly sensitive to the meltwater forcings prescribed in each simulation, which are applied in different ways due to limited paleo-constraints. Meltwater forcing associated with the Meltwater Pulse 1A (MWP1A) event results in subsurface warming that is most pronounced in the Amundsen and Bellingshausen Sea sector in both models. Although modelled centennial-scale rates of temperature and accumulation change are reasonable, clear model–proxy mismatches are observed with regard to the timing and duration of the Antarctic Cold Reversal (ACR) and Younger Dryas–early Holocene warming, which may suggest model bias in large-scale ocean circulation, biases in temperature reconstructions from proxy records, or that the MWP1A and 1B events are inadequately represented in these simulations. The incorporation of dynamic ice sheet models in future transient climate simulations could aid in improving meltwater forcing representation, and thus model–proxy agreement, through this time interval.

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“…Several theories have been put forth, striving to explain the enigmatic MPT (Raymo and Huybers, 2008). They include a shift in subglacial conditions underneath the Laurentide Ice Sheet (regolith hypothesis by Clark and Pollard, 1998), the inception of a large North American Ice Sheet (Bintanja and van de Wal, 2008) or marine East Antarctic Ice Sheet by Raymo et al (2006), ice bedrock climate feedbacks , the buildup of large ice sheets between MIS24 and 22 identified by Elderfield et al (2012), or the combination of changes in ice-sheet dynamics and the carbon cycle (Chalk et al, 2017). Ultimately, it seems likely that an interplay of the various proposed processes culminated in the MPT.…”

Section: Introductionmentioning

confidence: 99%

Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice

et al. 2019

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Abstract. The international endeavour to retrieve a continuous ice core, which spans the middle Pleistocene climate transition ca. 1.2–0.9 Myr ago, encompasses a multitude of field and model-based pre-site surveys. We expand on the current efforts to locate a suitable drilling site for the oldest Antarctic ice core by means of 3-D continental ice-sheet modelling. To this end, we present an ensemble of ice-sheet simulations spanning the last 2 Myr, employing transient boundary conditions derived from climate modelling and climate proxy records. We discuss the imprint of changing climate conditions, sea level and geothermal heat flux on the ice thickness, and basal conditions around previously identified sites with continuous records of old ice. Our modelling results show a range of configurational ice-sheet changes across the middle Pleistocene transition, suggesting a potential shift of the West Antarctic Ice Sheet to a marine-based configuration. Despite the middle Pleistocene climate reorganisation and associated ice-dynamic changes, we identify several regions conducive to conditions maintaining 1.5 Myr (million years) old ice, particularly around Dome Fuji, Dome C and Ridge B, which is in agreement with previous studies. This finding strengthens the notion that continuous records with such old ice do exist in previously identified regions, while we are also providing a dynamic continental ice-sheet context.

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Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr

Cited by 35 publications

References 57 publications

Five decades of radioglaciology

Five decades of radioglaciology

Deglacial evolution of regional Antarctic climate and Southern Ocean conditions in transient climate simulations

Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice

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Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr

Cited by 35 publications

References 57 publications

Five decades of radioglaciology

Five decades of radioglaciology

Deglacial evolution of regional Antarctic climate and Southern Ocean conditions in transient climate simulations

Modelling the Antarctic Ice Sheet across the mid-Pleistocene transition – implications for Oldest Ice

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Accumulation patterns around Dome C, East Antarctica, in the last 73 kyr