Progress in Numerical Modeling of Antarctic Ice-Sheet Dynamics

Pattyn, Frank; Favier, Lionel; Sun, Sainan; Durand, Gaël

doi:10.1007/s40641-017-0069-7

Cited by 61 publications

(55 citation statements)

References 138 publications

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“…This requires the availability of surface velocity data covering the whole AIS, as well as spatially comprehensive data of ice shelf thinning over all major ice shelves. Recent advances in numerical modeling and improved coverage of surface velocity data across the AIS have, however, now made large-scale data assimilation of observed velocities possible (Cornford et al, 2015;Pattyn et al, 2017). Combined with robust estimation of ice shelf buttressing and its impact on ice flow (Arthern et al, 2015;Cornford et al, 2013;, direct measurements of ice shelf thickness change (Paolo et al, 2015) now allow us to quantify the instantaneous impact of observed ice shelf thinning on the ice sheet mass loss due to changes in buttressing, using wellestablished glacier-mechanical principles.…”

Section: 1029/2019gl085027mentioning

confidence: 99%

Instantaneous Antarctic ice sheet mass loss driven by thinning ice shelves

Gudmundsson

Paolo

Adusumilli

et al. 2019

Geophysical Research Letters

158

144

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Recent observations show that the rate at which the Antarctic ice sheet (AIS) is contributing to sea level rise is increasing. Increases in ice-ocean heat exchange have the potential to induce substantial mass loss through the melting of its ice shelves. Lack of data and limitations in modeling, however, has made it challenging to quantify the importance of ocean-induced changes in ice shelf thickness as a driver for ongoing mass loss. Here, we use a numerical ice sheet model in combination with satellite observations of ice shelf thinning from 1994 to 2017 to quantify instantaneous changes in ice flow across all AIS grounding lines, resulting from changes in ice shelf buttressing alone. Our process-based predictions are in good agreement with observed spatial patterns of ice loss, providing support for the notion that a significant portion of the current ice loss of the AIS is ocean driven and caused by a reduction in ice shelf buttressing.Plain Language Summary The Antarctic ice sheet is currently losing mass, but the causes for the mass loss remain unclear. It has been suggested that the reduction in the thickness of the floating ice shelves that surround the ice sheet, for example, due to ocean warming or changes in ocean circulation, may be responsible for some of the observed ice loss. However, this hypothesis has remained untested. Here, we use a state-of-the art numerical ice flow model to calculate the direct mass loss due to observed changes in ice shelves between 1994 and 2017. We find that the magnitude and spatial variability of modelled changes of inland ice are in good agreement with observations, suggesting that a substantial portion of the recent ice loss from the grounded Antarctic ice sheet has been driven by changes in its thinning ice shelves. The process we consider (ice shelf buttressing) relates to changes in forces within the ice alone and is therefore effectively instantaneous (i.e., only limited by the speed of stress transition within the ice). Besides providing a possible explanation for a large part of the ongoing mass loss, this finding also shows that we are not protected against the impact of the Antarctic ice sheet on global sea levels by a long response time.

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Section: 1029/2019gl085027mentioning

confidence: 99%

Instantaneous Antarctic ice sheet mass loss driven by thinning ice shelves

Gudmundsson

Paolo

Adusumilli

et al. 2019

Geophysical Research Letters

158

144

View full text Add to dashboard Cite

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“…As a result, several key features of ice flow models have improved greatly, including: (1) the approximation used for the stress balance equations (Figure 3), (2) the discretization of model domains (Figure 4), and (3) the representation of grounding lines and ice front migration. This section summarizes these improvements; for more details on recent ISM development, we refer readers to Goelzer et al (2017) and Pattyn et al (2017).…”

Section: An Improved Generation Of Modelsmentioning

confidence: 99%

Projections of Future Sea Level Contributions from the Greenland and Antarctic Ice Sheets: Challenges Beyond Dynamical Ice Sheet Modeling

Nowicki¹,

Nasa²,

Seroussi³

2018

Oceanog

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“…Glaciers and ice caps are too small to be resolved by their coarse spatial resolution. Ice sheets are large enough, but the main physical processes determining their response to climate change are still uncertain (Church et al, 2013;Deconto & Pollard, 2016;Pattyn et al, 2017). Also, their long time scale of adjustment and sensitivity to small circulation and temperature biases still make it challenging to include them in fully coupled models (Joughin et al, 2012;Lenaerts et al, 2015;Vizcaíno et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Uncertainty in Sea Level Rise Projections Due to the Dependence Between Contributors

Bars

2018

Earth's Future

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Sea level rises at an accelerating pace threatening coastal communities all over the world. In this context sea level projections are key tools to help risk mitigation and adaptation. Projections are often made using models of the main contributors to sea level rise (e.g., thermal expansion, glaciers, and ice sheets). To obtain the total sea level these contributions are added; therefore, the uncertainty of total sea level depends on the correlation between the uncertainties of the contributors. This fact is important to understand the differences in the uncertainty of sea level projections from different methods. Using two process‐based models to project sea level for the 21st century, we show how to model the correlation structure and its time dependence. In these models the correlation primarily arises from uncertainty of future global mean surface temperature that correlates with almost all contributors. Assuming that sea level contributors are independent of each other, an assumption made in many sea level projections underestimates the uncertainty in sea level projections. As a result, high‐end low probability events that are important for decision making are underestimated. The uncertainty in the strength of the dependence between contributors is also explored. New dependence relations between the uncertainty of dynamical processes and surface mass balance in glaciers and ice sheets are introduced in our model. Total sea level uncertainty is found to be as sensitive to the dependence between contributors as to uncertainty in certain individual contributors like thermal expansion and Greenland ice sheet.

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Progress in Numerical Modeling of Antarctic Ice-Sheet Dynamics

Cited by 61 publications

References 138 publications

Instantaneous Antarctic ice sheet mass loss driven by thinning ice shelves

Instantaneous Antarctic ice sheet mass loss driven by thinning ice shelves

Projections of Future Sea Level Contributions from the Greenland and Antarctic Ice Sheets: Challenges Beyond Dynamical Ice Sheet Modeling

Uncertainty in Sea Level Rise Projections Due to the Dependence Between Contributors

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