Initialization of ice-sheet forecasts viewed as an inverse Robin problem
TLDR
In this article, the authors describe an algorithm for specifying the initial state of an ice-sheet model, given spatially continuous observations of the surface elevation, the velocity at the surface and the thickness of the ice.Abstract:
As simulations of 21st-century climate start to include components with longer timescales, such as ice sheets, the initial conditions for those components will become critical to the forecast. This paper describes an algorithm for specifying the initial state of an ice-sheet model, given spatially continuous observations of the surface elevation, the velocity at the surface and the thickness of the ice. The algorithm can be viewed as an inverse procedure to solve for the viscosity or the basal drag coefficient. It applies to incompressible Stokes flow over an impenetrable boundary, and is based upon techniques used in electric impedance tomography; in particular, the minimization of a type of cost function proposed by Kohn and Vogelius. The algorithm can be implemented numerically using only the forward solution of the Stokes equations, with no need to develop a separate adjoint model. The only requirement placed upon the numerical Stokes solver is that boundary conditions of Dirichlet, Neumann and Robin types can be implemented. As an illustrative example, the algorithm is applied to shear flow down an impenetrable inclined plane. A fully three-dimensional test case using a commercially available solver for the Stokes equations is also presented.read more
Citations
More filters
Journal ArticleDOI
Retreat of Pine Island Glacier controlled by marine ice-sheet instability
Lionel Favier,Lionel Favier,Gaël Durand,Gaël Durand,Stephen Cornford,GH Gudmundsson,GH Gudmundsson,Olivier Gagliardini,Olivier Gagliardini,Olivier Gagliardini,Fabien Gillet-Chaulet,Fabien Gillet-Chaulet,Thomas Zwinger,Antony J. Payne,A. M. Le Brocq +14 more
TL;DR: The authors used three ice-flow models to investigate the stability of the Pine Island Glacier and found that the grounding line could retreat a further 40 km, which is equivalent to a rise in sea level of 3.5-10 mm over a 20 year period.
Journal ArticleDOI
Capabilities and performance of Elmer/Ice, a new-generation ice sheet model
Olivier Gagliardini,Olivier Gagliardini,Thomas Zwinger,Fabien Gillet-Chaulet,G. Durand,Lionel Favier,B. de Fleurian,Ralf Greve,Mika Malinen,Carlos Martín,Peter Råback,Juha Ruokolainen,M. Sacchettini,Martina Schäfer,Hakime Seddik,Jonas Thies +15 more
TL;DR: Elmer/Ice as mentioned in this paper is a parallel finite-element model based on the open-source multi-physics code Elmer that solves the full-Stokes equations, for isotropic but also anisotropic ice rheology, resolves the grounding line dynamics as a contact problem, and contains various basal friction laws.
Journal ArticleDOI
Ice-sheet mass balance and climate change
Edward Hanna,Francisco Navarro,Frank Pattyn,Catia M. Domingues,Xavier Fettweis,Erik R. Ivins,Robert J. Nicholls,Catherine Ritz,Ben Smith,Slawek Tulaczyk,Pippa L. Whitehouse,H. Jay Zwally +11 more
TL;DR: The past six years of progress are discussed and key problems that remain are examined, including whether East Antarctica has been gaining or losing ice mass over the past 20 years, and uncertainties in ice-mass change for West Antarctica and the Antarctic Peninsula remain large.
Journal ArticleDOI
Greenland ice sheet contribution to sea-level rise from a new-generation ice-sheet model
Fabien Gillet-Chaulet,Olivier Gagliardini,Olivier Gagliardini,Hakime Seddik,Maëlle Nodet,Gaël Durand,Catherine Ritz,Thomas Zwinger,Ralph Greve,David G. Vaughan +9 more
TL;DR: In this article, the authors present a new generation prognostic model which reproduces the current patterns of rapid ice flow and investigate possible bounds for the next century ice-sheet mass loss.
Journal ArticleDOI
Adaptive mesh, finite volume modeling of marine ice sheets
Stephen Cornford,Daniel F. Martin,Daniel Graves,Douglas F. Ranken,Anne M. Le Brocq,Rupert Gladstone,Antony J. Payne,Esmond G. Ng,William H. Lipscomb +8 more
TL;DR: A block-structured finite volume method with adaptive mesh refinement (AMR) for three dimensional ice sheets, which allows to discretize a narrow region around the grounding line at high resolution and the remainder of the ice sheet at low resolution.
References
More filters
Journal ArticleDOI
Satellite Radar Interferometry for Monitoring Ice Sheet Motion: Application to an Antarctic Ice Stream
TL;DR: The combined use of SRI and other satellite methods is expected to provide data that will enhance the understanding of ice stream mechanics and help make possible the prediction of ice sheet behavior.
Journal ArticleDOI
Determining conductivity by boundary measurements
Robert V. Kohn,Michael Vogelius +1 more
TL;DR: In this article, Calderon poses the question: "Is it possible to determine the conductivite thermique of an object by means of mesures statiques de la temperature and du flux de chaleur a la limite?"
Journal ArticleDOI
Large‐scale ice flow over a viscous basal sediment: Theory and application to ice stream B, Antarctica
TL;DR: In this article, the authors compare the observed flow of ice stream B to finite element simulations incorporating a viscous basal till and conclude that a simple till is sufficient to explain the current velocity profile.
Journal ArticleDOI
A BVP solver based on residual control and the Maltab PSE
TL;DR: Theoretical and software developments resulting in bvp4c, a capable BVP solver that is exceptionally easy to use are presented.
Journal ArticleDOI
Mass balance of the Antarctic ice sheet
TL;DR: Mass gains from accumulating snow, particularly on the Antarctic Peninsula and within East Antarctica, exceed the ice dynamic mass loss from West Antarctica, which exacerbates the difficulty of explaining twentieth century sea-level rise.