Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica

Schodlok, Michael; Menemenlis, Dimitris; Rignot, Eric; Studinger, M.

doi:10.3189/2012aog60a073

Cited by 149 publications

(173 citation statements)

References 32 publications

Supporting

Mentioning

164

Contrasting

Order By: Relevance

“…Our results show that precise estimates of basal melting under floating ice are required and essential for constraining the evolution of glacier dynamics, as a modest increase of 10 % in basal melting rates impacts ice sheet dynamics. To achieve this goal, however, progress is necessary in the modeling of ice-ocean interactions beneath the ice shelves with coupled ice-sheet-ocean-atmosphere models (Schodlok et al, 2012). Finally, our simulations suggest that the acceleration of Pine Island Glacier will continue to propagate inland and its mass loss will continue for decades to come, even if the oceanic conditions return to their state prior to the 1990s and the grounding line position remains stable for a few decades.…”

Section: Discussionmentioning

confidence: 98%

“…Melting rates are kept constant throughout the simulations, while we know that changes in ice shelf cavity will affect their amplitude and spatial distribution (Schodlok et al, 2012). We choose not to change the pattern of basal melting, as we do not know how changes in ice shelf cavity will impact oceanic circulation and basal melting rates, and our results are therefore likely to be conservative estimates of changes.…”

Section: Discussionmentioning

confidence: 99%

“…The grounding line position corresponds to the 2007 grounding line position derived from differential satellite synthetic-aperture radar interferometry (DInSAR) from ERS-1 and 2, RADARSAT-1 and 2 and ALOS PALSAR (Rignot et al, 2011b. We rely on melting rate reconstructions from the MITgcm using the OIB bathymetry (Schodlok et al, 2012). The melting rate is an average over a year and is kept constant throughout the simulation, so no additional melting is introduced if ice starts floating.…”

Section: Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

et al. 2014

View full text Add to dashboard Cite

Abstract. Pine Island Glacier, a major contributor to sea level rise in West Antarctica, has been undergoing significant changes over the last few decades. Here, we employ a three-dimensional, higher-order model to simulate its evolution over the next 50 yr in response to changes in its surface mass balance, the position of its calving front and oceaninduced ice shelf melting. Simulations show that the largest climatic impact on ice dynamics is the rate of ice shelf melting, which rapidly affects the glacier speed over several hundreds of kilometers upstream of the grounding line. Our simulations show that the speedup observed in the 1990s and 2000s is consistent with an increase in sub-ice-shelf melting. According to our modeling results, even if the grounding line stabilizes for a few decades, we find that the glacier reaction can continue for several decades longer. Furthermore, Pine Island Glacier will continue to change rapidly over the coming decades and remain a major contributor to sea level rise, even if ocean-induced melting is reduced.

show abstract

Section: Discussionmentioning

confidence: 98%

Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

et al. 2014

View full text Add to dashboard Cite

show abstract

“…Accurate knowledge of grounding line positions as well as their evolution in time is therefore critical to understand ice sheet dynamics. Grounding lines are indeed a fundamental control of marine ice sheet stability (van der Veen, 1985;Hindmarsh and Le Meur, 2001), and they also determine the shape of ice-shelf cavities, which affect oceaninduced melting rates (Schodlok et al, 2012). Grounding line dynamics are strongly non-linear, with long episodes of relative stability interrupted by significant retreat, this evolution being controlled, among other factors, by basal topography (Weertman, 1974;Durand et al, 2009b).…”

Section: Introductionmentioning

confidence: 99%

Hydrostatic grounding line parameterization in ice sheet models

et al. 2014

View full text Add to dashboard Cite

Abstract. Modeling of grounding line migration is essential to accurately simulate the behavior of marine ice sheets and investigate their stability. Here, we assess the sensitivity of numerical models to the parameterization of the grounding line position. We run the MISMIP3D benchmark experiments using the Ice Sheet System Model (ISSM) and a two-dimensional shelfy-stream approximation (SSA) model with different mesh resolutions and different sub-element parameterizations of grounding line position. Results show that different grounding line parameterizations lead to different steady state grounding line positions as well as different retreat/advance rates. Our simulations explain why some vertically depth-averaged model simulations deviate significantly from the vast majority of simulations based on SSA in the MISMIP3D benchmark. The results reveal that differences between simulations performed with and without sub-element parameterization are as large as those performed with different approximations of the stress balance equations in this configuration. They also demonstrate that the reversibility test is passed at relatively coarse resolution while much finer resolutions are needed to accurately capture the steady-state grounding line position. We conclude that fixed grid SSA models that do not employ such a parameterization should be avoided, as they do not provide accurate estimates of grounding line dynamics, even at high spatial resolution. For models that include sub-element grounding line parameterization, in the MISMIP3D configuration, a mesh resolution finer than 2 km should be employed.

show abstract

“…To constrain the range of ice shelf melt rates, we calculate the ice shelf melt rate with mass conservation as in using the 2008 velocity, ice shelf thickness from BEDMAP-2, and the bathymetry of ASE to find a maximum ice shelf melt rate 10 at 125 m/yr, or 50% larger than the first scenario. In 2007, which was a warm year, the nearby Pine Island Glacier experienced ∼50 % more melt compared to 1992 (Schodlok et al, 2012). Therefore, in the second scenario, we increase the maximum ice shelf melt rate by 50 % to 120 m/yr to represent warm ocean conditions.…”

mentioning

confidence: 99%

Retreat of Thwaites Glacier, West Antarctica, over the next 100 years using various ice flow models, ice shelf melt scenarios and basal friction laws

Yu¹,

Rignot²,

Seroussi³

et al. 2018

Preprint

Self Cite

View full text Add to dashboard Cite

Abstract. Thwaites Glacier (TG), West Antarctica, experiences rapid, potentially irreversible grounding line retreat and mass loss in response to enhanced ice shelf melting. Several numerical models of TG have been developed recently, showing a large spread in the evolution of the glacier in the coming decades to a century. It is, however, not clear how different parameterizations of basal friction and ice shelf melt or different approximations in ice stress balance affect projections.Here, we simulate the evolution of TG using different ice shelf melt, basal friction laws and ice sheet models of varying levels of complexity to 5 quantify the effect of these model configurations on the results. We find that the grounding line retreat and its sensitivity to ocean forcing is enhanced when a full-Stokes model is used, ice shelf melt is applied on partially floating elements, and a Budd friction is used. Initial conditions also impact the model results. Yet, all simulations suggest a rapid, sustained retreat along the same preferred pathway. The highest retreat rate occurs on the eastern side of the glacier and the lowest rate on a subglacial ridge on the western side. All the simulations indicate that TG will undergo an accelerated retreat once it retreats past the 10 western ridge. Combining the results, we find the uncertainty is small in the first 30 years, with a cumulative contribution to sea level rise of 5 mm, similar to the current rate. After 30 years, the mass loss depends on the model configurations, with a 300% difference over the next 100 years, ranging from 14 to 42 mm. IntroductionThwaites Glacier (TG), located in the Amundsen Sea Embayment (ASE) sector of West Antarctica, is one of the largest ice 15 dischargers in Antarctica, with a potential to raise global mean sea level by 59 cm, and one of the largest contributors to the mass loss from Antarctica (Holt et al., 2006;Mouginot et al., 2014). With a maximum speed over 4,000 m/yr and a width of nearly 120 km (Fig. 1a), the glacier discharged 126 Gt of ice into the ocean in 2014 , nearly three times as much as Jakobshavn Isbrae, the largest discharger of ice in Greenland (Howat et al., 2011). Over the past decade, the rate of mass loss of TG has increased from 28 Gt/yr in 2006 to 50 Gt/yr in 2014 (Medley et al., 2014;Mouginot et al., 2014; Rignot, 20 2008). The grounding line of TG has retreated by 14 km from 1992 to 2011 along its fast flowing main trunk . The surface has thinned at a rate of about 4 m/yr near the grounding line and more than 1 m/yr about 100 km inland (Pritchard et al., 2009). The rate of change in mass loss increased from 2.7 Gt/yr 2002. If these rates were to maintain over the coming decades, they would raise global sea level by, respectively, 41, 48 and 81 mm by 2100.The rapid mass loss and grounding line retreat of TG have been attributed to an increase in ice shelf melt rate induced by warmer ocean conditions (Rignot, 2001; Joughin et al., 2014;Seroussi et al., 2017). The strengthening of westerlies around the Antarctic ...

show abstract

Sensitivity of the ice-shelf/ocean system to the sub-ice-shelf cavity shape measured by NASA IceBridge in Pine Island Glacier, West Antarctica

Cited by 149 publications

References 32 publications

Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

Sensitivity of the dynamics of Pine Island Glacier, West Antarctica, to climate forcing for the next 50 years

Hydrostatic grounding line parameterization in ice sheet models

Retreat of Thwaites Glacier, West Antarctica, over the next 100 years using various ice flow models, ice shelf melt scenarios and basal friction laws

Contact Info

Product

Resources

About