Thin-Film Flows with Wall Slip: An Asymptotic Analysis of Higher Order Glacier Flow Models

Schoof, Christian; Hindmarsh, Richard C. A.

doi:10.1093/qjmam/hbp025

Cited by 224 publications

(315 citation statements)

References 46 publications

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“…Such models are becoming readily available now (Pattyn et al 2008) but are computationally far more expensive and therefore unlikely to be used for longer-term simulations on an full ice sheet scale in the near future. Thus, it will be crucial to rigorously test and assess the validity of different approximations of flow physics such as the shallow-shelf approximation (MacAyeal (1989); Bueler and Brown (2009); and as used here), a depth-integrated hybrid approximation (Bassis 2010;Schoof and Hindmarsh 2010;Goldberg 2011) or the first-order Blatter/Pattyn type approximation (Blatter 1995;Pattyn 2003) against the full-Stokes case for a marine terminating boundary and in view of computational expense. Importantly, this requires also validation against real world data.…”

Section: Vertical Deformationmentioning

confidence: 99%

Understanding and Modelling Rapid Dynamic Changes of Tidewater Outlet Glaciers: Issues and Implications

Vieli¹,

Nick²

2011

The Earth's Cryosphere and Sea Level Change

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Recent dramatic acceleration, thinning and retreat of tidewater outlet glaciers in Greenland raises concern regarding their contribution to future sea-level rise. These dynamic changes seem to be parallel to oceanic and climatic warming but the linking mechanisms and forcings are poorly understood and, furthermore, large-scale ice sheet models are currently unable to realistically simulate such changes which provides a major limitation in our ability to predict dynamic mass losses. In this paper we apply a specifically designed numerical flowband model to Jakobshavn Isbrae (JIB), a major marine outlet glacier of the Greenland ice sheet, and we explore and discuss the basic concepts and emerging issues in our understanding and modelling ability of the dynamics of tidewater outlet glaciers. The modelling demonstrates that enhanced ocean melt is able to trigger the observed dynamic changes of JIB but it heavily relies on the feedback between calving and terminus retreat and therefore the loss of buttressing. Through the same feedback, other forcings such as reduced winter sea-ice duration can produce similar rapid retreat. This highlights the need for a robust representation of the calving process and for improvements in the understanding and implementation of forcings at the marine boundary in predictive ice sheet models. Furthermore, the modelling uncovers high sensitivity and rapid adjustment of marine outlet glaciers to perturbations at their marine boundary implying that care should be taken in interpreting or extrapolating such rapid dynamic changes as recently observed in Greenland.

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Section: Vertical Deformationmentioning

confidence: 99%

Understanding and Modelling Rapid Dynamic Changes of Tidewater Outlet Glaciers: Issues and Implications

Vieli¹,

Nick²

2011

The Earth's Cryosphere and Sea Level Change

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“…Therefore, hybrid lubrication/membrane models, such as HOM (Blatter 1995;Pattyn 2003), have been developed. Schoof and Hindmarsh (2010) established a theory for such hybrid models, which was missing until now. They developed asymptotic expansions for the solution to the Blatter equations in order to obtain a depth-integrated model that describes both fast and slow sliding.…”

Section: Transition Zonesmentioning

confidence: 99%

Representing Grounding Line Dynamics in Numerical Ice Sheet Models: Recent Advances and Outlook

Docquier¹,

Perichon²,

Pattyn³

2011

The Earth's Cryosphere and Sea Level Change

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Recent satellite observations of the Antarctic and Greenland ice sheets show accelerated ice flow and associated ice sheet thinning along coastal outlet glaciers in contact with the ocean. Both processes are the result of grounding line retreat due to melting at the grounding line (the grounding line is the contact of the ice sheet with the ocean, where it starts to float and forms an ice shelf or ice tongue). Such rapid ice loss is not yet included in large-scale ice sheet models used for IPCC projections, as most of the complex processes are poorly understood. Here we report on the state-of-the art of grounding line migration in marine ice sheets and address different ways in which grounding line migration can be attributed and represented in ice sheet models. Using onedimensional ice flow models of the ice sheet/ice shelf system we carried out a number of sensitivity experiments with different spatial resolutions and stress approximations. These are verified with semi-analytical steady state solutions. Results show that, in large-scale finite-difference models, grounding line migration is dependent on the numerical treatment (e.g. staggered/non-staggered grid) and the level of physics involved (e.g. shallow-ice/ shallow-shelf approximation).

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“…BISICLES solves the Schoof-Hindmarsh approximation (L1L2) of the full Stokes equations on an adaptive horizontal grid produced with the Chombo adaptive mesh refinement toolkit. The L1L2 approximation is based on the Shallow Shelf Approximation (SSA) in which the vertical shearing terms are neglected in the expression of the strain rate and stress tensors but are included in the effective viscosity expression [Schoof and Hindmarsh, 2010]. While the effective viscosity calculation incorporates vertically integrated stresses, the component of mass flux due .…”

Section: Ice Sheet Modelmentioning

confidence: 99%

Antarctic ice rise formation, evolution, and stability

Favier

Pattyn

2015

Geophysical Research Letters

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Antarctic ice rises originate from the contact between ice shelves and one of the numerous topographic highs emerging from the edge of the continental shelf. While investigations of the Raymond effect indicate their millennial‐scale stability, little is known about their formation and their role in ice shelf stability. Here we present for the first time the simulation of an ice rise using the BISICLES model. The numerical results successfully reproduce several field‐observable features, such as the substantial thinning downstream of the ice rise and the successive formation of a promontory and ice rise with stable radial ice flow center, showing that ice rises are formed during the ice sheet deglaciation. We quantify the ice rise buttressing effect, found to be mostly transient, delaying grounding line retreat significantly but resulting in comparable steady state positions. We demonstrate that ice rises are key in controlling simulations of Antarctic deglaciation.

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Thin-Film Flows with Wall Slip: An Asymptotic Analysis of Higher Order Glacier Flow Models

Cited by 224 publications

References 46 publications

Understanding and Modelling Rapid Dynamic Changes of Tidewater Outlet Glaciers: Issues and Implications

Understanding and Modelling Rapid Dynamic Changes of Tidewater Outlet Glaciers: Issues and Implications

Representing Grounding Line Dynamics in Numerical Ice Sheet Models: Recent Advances and Outlook

Antarctic ice rise formation, evolution, and stability

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