A. J. Payne

D. F. Martin

E. G. Ng

Gagliardini

Nias

S. L. Cornford

V. Lee

ABSTRACT
                  
                    At least in conventional hydrostatic ice-sheet models, the numerical error associated with grounding line dynamics can be reduced by modifications to the discretization scheme. These involve altering the integration formulae for the basal traction and/or driving stress close to the grounding line and exhibit lower – if still first-order – error in the MISMIP3d experiments. MISMIP3d may not represent the variety of real ice streams, in that it lacks strong lateral stresses, and imposes a large basal traction at the grounding line. We study resolution sensitivity in the context of extreme forcing simulations of the entire Antarctic ice sheet, using the BISICLES adaptive mesh ice-sheet model with two schemes: the original treatment, and a scheme, which modifies the discretization of the basal traction. The second scheme does indeed improve accuracy – by around a factor of two – for a given mesh spacing, but
                    
                      
                        
                        $\lesssim 1$
                      
                    
                    km resolution is still necessary. For example, in coarser resolution simulations Thwaites Glacier retreats so slowly that other ice streams divert its trunk. In contrast, with
                    
                      
                        
                        $\lesssim 1$
                      
                    
                    km meshes, the same glacier retreats far more quickly and triggers the final phase of West Antarctic collapse a century before any such diversion can take place

Cornford, SL

Martin, DF

Lee, V

Payne, AJ

Ng, EG

eScholarship - University of California

Adaptive mesh refinement versus subgrid friction interpolation in simulations of Antarctic ice dynamics

Stephen Cornford

Cronfa at Swansea University

At least in conventional hydrostatic ice-sheet models, the numerical error associated with grounding line dynamics can be reduced by modifications to the discretization scheme. These involve altering the integration formulae for the basal traction and/or driving stress close to the grounding line and exhibit lower – if still first-order – error in the MISMIP3d experiments. MISMIP3d may not represent the variety of real ice streams, in that it lacks strong lateral stresses, and imposes a large basal traction at the grounding line. We study resolution sensitivity in the context of extreme forcing simulations of the entire Antarctic ice sheet, using the BISICLES adaptive mesh ice-sheet model with two schemes: the original treatment, and a scheme, which modifies the discretization of the basal traction. The second scheme does indeed improve accuracy – by around a factor of two – for a given mesh spacing, but $\lesssim 1$ km resolution is still necessary. For example, in coarser resolution simulations Thwaites Glacier retreats so slowly that other ice streams divert its trunk. In contrast, with $\lesssim 1$ km meshes, the same glacier retreats far more quickly and triggers the final phase of West Antarctic collapse a century before any such diversion can take place

Cornford, Stephen

Martin, Daniel

Lee, Victoria

Payne, Tony

Ng, Esmond

Explore Bristol Research

ABSTRACTAt least in conventional hydrostatic ice-sheet models, the numerical error associated with grounding line dynamics can be reduced by modifications to the discretization scheme. These involve altering the integration formulae for the basal traction and/or driving stress close to the grounding line and exhibit lower – if still first-order – error in the MISMIP3d experiments. MISMIP3d may not represent the variety of real ice streams, in that it lacks strong lateral stresses, and imposes a large basal traction at the grounding line. We study resolution sensitivity in the context of extreme forcing simulations of the entire Antarctic ice sheet, using the BISICLES adaptive mesh ice-sheet model with two schemes: the original treatment, and a scheme, which modifies the discretization of the basal traction. The second scheme does indeed improve accuracy – by around a factor of two – for a given mesh spacing, but $\lesssim 1$ km resolution is still necessary. For example, in coarser resolution simulations Thwaites Glacier retreats so slowly that other ice streams divert its trunk. In contrast, with $\lesssim 1$ km meshes, the same glacier retreats far more quickly and triggers the final phase of West Antarctic collapse a century before any such diversion can take place.</jats:p

Crossref

Annals of Glaciology

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/E4C4E3039F1A310AF74EBF9C77A2447E/S0260305516000136a.pdf/div-class-title-adaptive-mesh-refinement-versus-subgrid-friction-interpolation-in-simulations-of-antarctic-ice-dynamics-div.pdf

Adaptive mesh refinement versus subgrid friction interpolation in simulations of Antarctic ice dynamics

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eScholarship - University of California

Cronfa at Swansea University

Explore Bristol Research

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