HR: 14:55h
AN: C43A-06 INVITED    [Abstracts]
TI: A Three-Dimensional, First-Order Model of ice Flow: Numerical Implementation, Validation, and Initial Application to Iceland and Greenland
AU: * Price, S F
EM: S.F.Price@bristol.ac.uk
AF: Bristol Glaciology Centre, University of Bristol, Bristol, BS8 1SS, United Kingdom
AU: Payne, A J
EM: A.J.Payne@bristol.ac.uk
AF: Bristol Glaciology Centre, University of Bristol, Bristol, BS8 1SS, United Kingdom
AU: Shepherd, A
EM: Andrew.Shepherd@ed.ac.uk
AF: School of Geosciences, University of Edinburgh, Edinburgh, EH8 9XP, United Kingdom
AB: We present a new, three-dimensional ice sheet model that accounts for vertical and horizontal stress gradients to first order. The horizontal stress balance equations are caste in terms of velocity gradients (e.g. Blatter [1995], the 'LMLa' scheme of Hindmarsh [2004]) by employing a constitutive relation for ice (Glen's flow law). The resulting coupled, non-linear elliptic equations are solved by the Finite Difference Method, using the iterative technique of Hindmarsh and Payne [1996] and the PETSc linear solver library. An innovative approach is used to incorporate first order surface and basal boundary conditions of Dirichlet, Neumann, and mixed types. We validate the model by comparing output against (1) analytical solutions for end-member geometries and boundary conditions, such as sheet flow, stream flow, and shelf flow, and (2) by comparing output against benchmarking experiments for full-stress and higher-order models (Pattyn and others, 2007). We present and discuss initial velocity and stress solutions for the Langjokull ice cap (Iceland) and the Greenland ice sheet, based on currently available ice sheet geometries and simplified assumptions about the effective viscosity.
DE: 0726 Ice sheets
DE: 0774 Dynamics
DE: 0776 Glaciology (1621, 1827, 1863)
DE: 0798 Modeling
SC: Cryosphere [C]
MN: 2007 Fall Meeting