SNIC
SUPR
SNIC SUPR
FROZEN - ICE SHEET MODELING
Dnr:

SNIC 2018/3-458

Type:

SNAC Medium

Principal Investigator:

Nina Kirchner

Affiliation:

Stockholms universitet

Start Date:

2018-10-01

End Date:

2019-04-01

Primary Classification:

10105: Computational Mathematics

Secondary Classification:

10503: Geosciences, Multidisciplinary

Allocation

Abstract

The project is a topical continuation of project SNIC 2015/1-311, 2016/1-175, 2017/1-142, 2017/1-389 and 2018/3-177. We simulate grounded ice sheets and attached floating ice shelves, on timescales ranging from 100 to 100.000 years. The equations which govern ice dynamics and which need to be solved are the full Stokes (FS) equations for the velocity field of the ice , coupled to a transport equation for the elevation of the surface of the ice. The Stokes equations have a nonlinear viscosity and are discretized by a finite element method. Simplifications of the equations are possible in parts of the ice domain called the shallow ice (SI) equations, and shallow shelf (SS) equations, respectively. Methods combining FS with SI, and FS with SS, are now implemented in Elmer/Ice, and are referred to as the ISCAL method (*Ahlkrona, J., Lötstedt, P., Kirchner, N., Zwinger, T.,(2016). Dynamically coupling the non-linear Stokes equations with the Shallow Ice Approximation in glaciology: Description and first application of the ISCAL method.  Journal of Computational Physics 308, 1-19,doi:10.1016/j.jcp.2015.12.025). *van Dongen, E., Kirchner, N., and others, including Lötstedt, P., von Sydow, L., Cheng, G.) in press. Dynamically coupling Full Stokes and Shallow Shelf Approximation for marine ice sheet flow using Elmer/Ice (v8.3). Geosci. Model Dev.; *Cheng, G., Lötstedt, P., von Sydow, L. (2017). Accurate and stable time stepping in ice sheet modeling. Journal of Computational Physics, 329: 29-47 ISCAL has been run succesfully on Beskow in the past, and we plan to extend ISCAL to include simulation of calving processes at ocean terminating glacier fronts. In order to better understand and model calving processes at the ice fronts of fjord-terminating glaciers, we take, for the first time in our project history, a look on the ocean-side where we will model fjord circulation and, especially, plume development along a calving front. For this, the software ROMS (Regional Ocean Modeling System) will be used. Once sufficient experience in ROMS is gained, ROMS and Elmer/Ice (and ISCAL) will be coupled through FISOC, the "Framework for Ice Sheet Ocean Coupling". http://elmerfem.org/elmerice/wiki/lib/exe/fetch.php?media=courses:2017:slides_rupert.pdf The team consists of one PhD student (Cheng Gong) at the Division of Scientific Computing at Uppsala University (UU), and, two Ph D students at Stockholm University (Holmes, Prakash). Three senior researchers (2 from UU - Lötstedt, von Sydow, 1 from SU - Kirchner) are part of the team.