TY  - JOUR
A1  - Winkelmann, Ricarda
A1  - Martin, Maria A.
A1  - Haseloff, Monika
A1  - Albrecht, Torsten
A1  - Bueler, Ed
A1  - Khroulev, C.
A1  - Levermann, Anders
T1  - The Potsdam parallel ice sheet model (PISM-PIK) - Part 1: Model description
JF  - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2  - We present the Potsdam Parallel Ice Sheet Model (PISM-PIK), developed at the Potsdam Institute for Climate Impact Research to be used for simulations of large-scale ice sheet-shelf systems. It is derived from the Parallel Ice Sheet Model (Bueler and Brown, 2009). Velocities are calculated by superposition of two shallow stress balance approximations within the entire ice covered region: the shallow ice approximation (SIA) is dominant in grounded regions and accounts for shear deformation parallel to the geoid. The plug-flow type shallow shelf approximation (SSA) dominates the velocity field in ice shelf regions and serves as a basal sliding velocity in grounded regions. Ice streams can be identified diagnostically as regions with a significant contribution of membrane stresses to the local momentum balance. All lateral boundaries in PISM-PIK are free to evolve, including the grounding line and ice fronts. Ice shelf margins in particular are modeled using Neumann boundary conditions for the SSA equations, reflecting a hydrostatic stress imbalance along the vertical calving face. The ice front position is modeled using a subgrid-scale representation of calving front motion (Albrecht et al., 2011) and a physically-motivated calving law based on horizontal spreading rates. The model is tested in experiments from the Marine Ice Sheet Model Intercomparison Project (MISMIP). A dynamic equilibrium simulation of Antarctica under present-day conditions is presented in Martin et al. (2011).
Y1  - 2011
U6  - https://doi.org/10.5194/tc-5-715-2011
SN  - 1994-0416
VL  - 5
IS  - 3
SP  - 715
EP  - 726
PB  - Copernicus
CY  - Göttingen
ER  - 
TY  - JOUR
A1  - Martin, Maria A.
A1  - Winkelmann, Ricarda
A1  - Haseloff, M.
A1  - Albrecht, Tanja
A1  - Bueler, Ed
A1  - Khroulev, C.
A1  - Levermann, Anders
T1  - The Potsdam parallel ice sheet model (PISM-PIK) - Part 2: Dynamic equilibrium simulation of the Antarctic ice sheet
JF  - The Cryosphere : TC ; an interactive open access journal of the European Geosciences Union
N2  - We present a dynamic equilibrium simulation of the ice sheet-shelf system on Antarctica with the Potsdam Parallel Ice Sheet Model (PISM-PIK). The simulation is initialized with present-day conditions for bed topography and ice thickness and then run to steady state with constant present-day surface mass balance. Surface temperature and sub-shelf basal melt distribution are parameterized. Grounding lines and calving fronts are free to evolve, and their modeled equilibrium state is compared to observational data. A physically-motivated calving law based on horizontal spreading rates allows for realistic calving fronts for various types of shelves. Steady-state dynamics including surface velocity and ice flux are analyzed for whole Antarctica and the Ronne-Filchner and Ross ice shelf areas in particular. The results show that the different flow regimes in sheet and shelves, and the transition zone between them, are captured reasonably well, supporting the approach of superposition of SIA and SSA for the representation of fast motion of grounded ice. This approach also leads to a natural emergence of sliding-dominated flow in stream-like features in this new 3-D marine ice sheet model.
Y1  - 2011
U6  - https://doi.org/10.5194/tc-5-727-2011
SN  - 1994-0416
VL  - 5
IS  - 3
SP  - 727
EP  - 740
PB  - Copernicus
CY  - Göttingen
ER  -