PISM

PISM
Name	PISM
Developer	University of Alaska Fairbanks; contributors from Alfred Wegener Institute for Polar and Marine Research, Utrecht University, University of California, Santa Cruz and others
Released	2001
Programming language	C++; Fortran
Operating system	Linux, macOS, Windows (via Cygwin)
Platform	x86_64
Genre	Ice sheet model; cryosphere modeling
License	GPL

PISM

PISM is an open-source, thermo-mechanical ice sheet modeling software designed for simulating ice flow, thermodynamics, and subglacial hydrology. It supports simulations of polar ice sheets and glaciers with applications in paleoclimate reconstruction, sea-level projection, and ice-sheet dynamics research. PISM integrates numerical methods and physical parameterizations to represent processes relevant to Greenland Ice Sheet, Antarctica, and regional ice masses.

Overview

PISM couples shallow ice and shallow shelf approximations with thermomechanical coupling to simulate ice dynamics, basal processes, and surface mass balance. It is designed for scalability on high-performance computing systems used by groups such as National Center for Atmospheric Research and Lawrence Berkeley National Laboratory. The codebase interoperates with climate model output from initiatives like Coupled Model Intercomparison Project archives and basin-scale data sets from MEaSUREs and ICESat. PISM has been applied in studies involving the Intergovernmental Panel on Climate Change assessment reports and in collaborations with institutions including British Antarctic Survey and Jet Propulsion Laboratory.

History

Development began in the early 2000s at institutions that included University of Alaska Fairbanks and Ohio State University, drawing on earlier theory from pioneers such as John Weertman and James H. C. Clarke. Subsequent contributions incorporated algorithms popularized in works by W. Jason Morgan and numerical formulations influenced by Thomas J. Kirk and others in computational glaciology. Over multiple major releases, PISM added parameterizations for sliding laws inspired by laboratory and field studies associated with Robin M. Bell and Richard B. Alley. The project matured alongside community codes such as Elmer/Ice, BISICLES, and ISSM, leading to cross-validation exercises with groups at ETH Zurich and University of Cambridge.

Features and Architecture

PISM employs a modular architecture combining a shallow ice approximation and a shallow shelf approximation to capture grounded and floating ice dynamics. The thermodynamics component solves enthalpy or temperature equations and interfaces with subglacial hydrology modules that represent basal water routing informed by concepts from Peter W. Nienow studies. Its numerical backbone uses finite-difference grids, implicit solvers, and multigrid preconditioners similar to approaches developed at Argonne National Laboratory and in the Trilinos Project. PISM supports adaptive time stepping, diagnostic outputs compatible with NetCDF conventions used by NASA, and coupling to atmospheric forcings from data sets produced by ECMWF and NOAA. The architecture allows extensions for calving laws, isostatic adjustment incorporating ideas from GIA research groups, and assimilation of observations from missions like CryoSat and Operation IceBridge.

Applications

Researchers apply PISM to reconstruct past ice-sheet configurations, project future contributions to sea level rise from ice masses, and investigate processes such as grounding line migration and marine ice-sheet instability examined in landmark studies by Sergienko and Weertman. Regional studies have utilized PISM for the Greenland and Antarctic sectors, including outlet glacier dynamics comparable to analyses by Rignot and Bindschadler. Paleoclimate experiments have linked PISM to PMIP-era forcings, and coupling experiments have used PISM output in Earth system models from centers like GFDL and NCAR. Cryo-hydrological investigations employ PISM for basal drainage studies informed by work from Ian Joughin and Glen M. Thomas.

Validation and Performance

Validation efforts compare PISM simulations with satellite altimetry from ICESat and ICESat-2, interferometric velocity fields from InSAR missions and in situ mass-balance observations collected by programs such as PROMICE and ITASE. Benchmarks include intercomparison with MISMIP and other community experiments coordinated by groups at University of Oslo and University of Washington. Performance scaling has been demonstrated on systems at National Energy Research Scientific Computing Center and European supercomputing facilities, with parallelization strategies informed by MPI implementations common to NERSC applications. Sensitivity studies explore parameter uncertainty using ensembles of forcings from CMIP archives.

Development and Community

PISM development is coordinated through version control platforms and contributor communities that include academics from University of Alaska Fairbanks, Alfred Wegener Institute for Polar and Marine Research, and collaborating labs. Users and developers engage via mailing lists, workshops at conferences such as AGU and EGU, and collaborative projects with groups at Columbia University and University of California, Santa Cruz. Documentation, test suites, and tutorials have been produced in partnership with training initiatives from NSF and summer schools hosted by International Glaciological Society.

Licensing and Availability

PISM is distributed under a permissive GPL-style license and is available for download and contribution through public code repositories. Binaries and source archives are packaged for common scientific computing environments and have been integrated into workflow systems used at facilities including XSEDE and PRACE. Academic users from institutions such as University of Oslo and WHOI routinely deploy PISM in research and teaching contexts.

Category:Glaciology software