PISM

Scientist for Modeling Ice Sheet–Climate Interaction at DMI

2025-03-17T00:00:00+00:00

The Danish Meteorological Institute (DMI), a leading research institution in climate and ice sheet modelling research, is offering a 3-year, full-time position as a Scientist for Modelling Ice Sheet–Climate Interaction.

Summary of the job advertisement

Are you interested in working with climate and ice sheet models? And motivated by understanding climate change in the Arctic and Antarctic regions? Here is a great opportunity to join DMI’s skilled team of climate researchers at the National Center for Climate Research.

The Danish Meteorological Institute (DMI) opens a 3 year, full-time position for a scientist to work on climate modeling with a focus on the polar regions and how the climate affects the Greenland and Antarctic ice sheets and vice versa.

As our new colleague, you will work with our Earth system model that includes ice sheets as interacting components in both hemispheres. Your responsibilities will include designing and executing model experiments, improving the model code, and enhancing the coupling between climate and ice sheets. You will collaborate with colleagues at DMI and participate in international consortia. Additionally, you will analyze modelled climate outputs, lead and contribute to scientific papers, and participate in developing grant applications with our team and external collaborators. Please use the following link for the complete job announcement and to apply for this position: https://candidate.hr-manager.net/ApplicationInit.aspx?cid=5001&ProjectId=187331&DepartmentId=6145&MediaId=5.

The current deadline is Sunday, the 30th of March.

For further details or questions about the position, please contact Christian Rodehacke at [telephone:] +45 3915 7453 or via mail at cr@dmi.dk. Alternatively, contact our acting Head of Unit, Mark R. Payne, at [telephone:] +45 2179 2620.

About the job

As our new colleague, you will work with our earth system model containing ice sheets in both hemispheres as interacting components: our comprehensive global earth system model EC-Earth, the Parallel Ice Sheet Model (PISM), and our surface mass balance model CISSEMBEL. You will be designing and executing model experiments and developing and improving the model code and climate-ice sheet coupling in collaboration with colleagues at DMI and as part of international consortia. You will also work with analyses of the modeled climate outputs, lead and contribute to scientific papers, and participate in developing new grant applications with the group and external collaborators. While working with the models and developing an improved coupling will be a core task, there will be some flexibility in deciding the weight between working with the model, running and analyzing experiments, and which particular topics and projects you work on.

Polar research is a key research area in the National Center for Climate Research (NCKF), and our work is carried out in close collaboration with national and international partners (e.g., through EU Horizon projects such as PROTECT and PolarRES). As part of NCKF, you will work in a department with a strong profile in both global and regional climate modeling, as well as remote sensing. The position in the framework of the Horizon Europe project “LIQUIDICE” collaborates with sister projects “ICELINK” and “CRYOSCOPE.”

About you

We are looking for a candidate with the following qualifications and experience:

A PhD degree in climate science, meteorology, oceanography, glaciology, or related fields (e.g., physics or engineering)
Experience with modeling, preferably of the ocean, atmosphere, or ice sheets (e.g. global or regional atmospheric or ocean modeling, numerical weather prediction, Earth system modeling, surface mass balance or ice sheet modeling)
Advanced programming skills (under Linux/Unix, scripting languages, e.g. Python or bash, high-level languages, e.g. Fortran or C++, etc.) and experience with HPC systems
Research experience working with polar (Arctic or Antarctic) climate is an advantage
Good communication skills in oral and written English

About the National Centre for Climate Research

The position is in the Danish National Center for Climate Research (NCKF) at DMI, which employs more than 70 climate scientists, including PhD students, junior and senior scientists. The companion Weather Research department employs researchers working with meteorology, oceanography and hydrology. We have a strong international profile, which is also reflected in the many nationalities employed and in the use of both English and Danish as working languages.

NCKF has been established with the purpose to conduct critical climate research for the Kingdom of Denmark (Denmark, Greenland and the Faroe Islands) and bring together climate knowledge, to form the basis for green transition and climate adaptation. The activities include assessments of observed and future climate change of the physical climate system, with focus on the Polar regions and on extreme weather and sea level around Denmark. Across the department, climate research builds on both global and regional modeling as well as observations from remote sensing, in-situ measurements and field work. NCKF also develops the Danish Climate Atlas (Klimaatlas) which contains detailed data about expected future changes in the climate of Denmark.

About DMI

DMI is part of the Ministry of Climate, Energy and Utilities. DMI is the government’s climate science advisor, creating and communicating knowledge about weather, climate and the sea to the Danish Realm. DMI’s warnings, weather forecasts and services safeguard life and infrastructure and provide a basis for planning in a changing climate. As an authority on weather, climate and the sea, DMI provides meteorological services to the Danish defence, emergency preparedness as well as civil aviation and shipping in Denmark and Greenland. DMI is one of the oldest state institutions in Denmark and celebrated its 150th anniversary in 2022.

We have approximately 400 employees, most of whom work at DMI’s new headquarters at Sankt Kjelds Gård in Østerbro. The new place have interior design that allows for an activity-based way of working.

Employment and Salary

Will be according to the Danish Law and Agreements. It will be possible to apply for an addition to the basic salary. DMI offers a flexible working week of 37 hours including a paid lunch break, and six weeks of paid vacation annually. If you come from abroad, there is a possibility for a reduced tax scheme the first 7 years.

For further details about the position, contact Christian Rodehacke (telephone: +45 3915 7453, mail cr@dmi.dk) or acting Head of Unit Mark R. Payne (telephone: +45 2179 2620).

At DMI, diversity is an important value for us, because we believe that an inclusive and versatile work environment strengthens task fulfilment. We work actively with diversity in our employee composition, which is reflected in our inclusive workplace with a balance between work life and family life. We encourage everyone to apply for the position regardless of age, gender, sexuality, religion or ethnicity.

Application

Send your motivated cover letter and a curriculum vitae, so we have it no later than Sunday the 30th of March. We expect to conduct interviews during weeks 14-15. The invitation will be sent via email.

PISM 2.2.1 is out

2025-03-17T00:00:00+00:00

We are pleased to announce the release of PISM v2.2.1.

Changes since v2.2.0

Fixed a minor bug: EISMINT II simplified geometry experiments should use the "cold" (temperature-based) energy conservation model. In PISM 2.2.0 the EISMINT II default of energy.model was mistakenly set to "none", i.e. isothermal mode without energy conservation.

To get correct behavior with PISM 2.2.0 run pism -energy cold -eisII \... instead of pism -eisII \....

Notable changes compared to v2.1

All executables and scripts installed in the bin sub-directory of PISM's installation location start with "pism" to make it easier to recognize ones that belong to PISM, especially when using a .deb package to install it.
Rename the pismr executable to pism.
Remove the pismv executable. Use pism -test X to run a verification test X.
Add some automatic testing on macOS.
Use pkg-config to look for all the dependencies that support it.
Add the CMake flag Pism_PKG_CONFIG_STATIC to tell CMake to use the \--static flag when using pkg-config. See issue 529(https://github.com/pism/pism/issues/529).
Add VERSION to ensure that tarballs with PISM's sources (e.g. archived by Zenodo) contain appropriate version info.
Update some examples in examples/marine.
Fix an bug reported by Ken Mankoff: scripts in examples/antarctica/ required PISM built with PROJ.
Add a section about citing PISM to the manual; remove redundant and possibly inconsistent recommendations elsewhere in PISM's docs.
Add a section about publishing PISM results to the manual. This section covers archiving the code, model inputs and outputs, etc.
Add the configuration parameter energy.model (choices: none, cold, enthalpy); remove energy.enabled and energy.temperature_based.
All bed deformation models use the load averaged over the duration of the (usually long) bed deformation time step (see issue 525(https://github.com/pism/pism/issues/525)). This requires saving the time integral of the load since the last bed deformation update (variable bed_def_load_accumulator and the time of the last update time_bed_deformation) as a part of the model state and reading them when re-starting the model. Rename bed_deformation.lc.update_interval to bed_deformation.update_interval since now all bed deformation models use this parameter. Add a new diagnostic variable: bed_def_load, the load used during the last bed deformation update.
Replace the serial connected component labeling algorithm with a parallel version (see pull request 547(https://github.com/pism/pism/pull/547) for details). This should improve strong scaling of the ocean model PICO and (less noticeably) of some other PISM components.
Require CMake 3.16 or newer.
Support the current PETSc version (3.22).
Update the oldest supported PETSc version from 3.7 to 3.11. (PISM's code still works with PETSc 3.7 and newer, but testing with PETSc older than 3.11 requires Python 2.7.x, which is no longer supported.)
Refactor the SSAFD solver, adding the ability to use PETSc's infrastructure to manage Picard iterations (and even use Newton iterations with a finite difference approximation of the Jacobian computed using coloring). Unfortunately this approach appears to be more fragile than the old one, so the default solver implementation remains the same. On the plus side, we get the ability to compute and save the SSAFD residual, which may help one analyze the quality of a velocity approximation produced by the SSAFD solver.
Create a Debian (Ubuntu) PISM package. This work required a number of changes to follow best practices when installing software in a standard location. For example: Python scripts in util/ are installed in /usr/share/pism/bin.
Add a configuration flag stress_balance.ssa.fd.upstream_surface_slope_approximation. If "yes" (the default), use the first order "upstream" (more accurately: "uphill") biased FD approximation. This reduces oscillations of velocity approximations produced by SSAFD in areas where the surface slope is large (e.g. near the grounding line).
Add a new diagnostic quantity: ice_mass_transport_across_grounding_line (in Gt/year). This quantity is similar to the 2D grounding_line_flux, but designed to be easily comparable to tendency_of_ice_mass_due_to_discharge and similar.
Use "kelvin" (lowercase "k") in all temperature units and implement other similar changes to make PISM output files compatible with conventions used by xarray.
Add flexible re-projection and interpolation (including conservative interpolation) using YAC(https://dkrz-sw.gitlab-pages.dkrz.de/yac/index.html). This work makes it possible to set up a PISM simulation using a grid in one projection and read inputs from NetCDF files that use different grids and projections (with some limitations). This should reduce the amount of pre-processing needed to use bed topography data sets (such as BedMachine), regional climate model outputs, etc.
Improve support for coordinate reference system specification following Climate and Forecasting conventions.
Add the configuration parameter grid.file and remove options -x_range, -y_range and -refinement_factor. The parameter grid.file specifies the grid definition file used to set the coordinate reference system plus default domain and grid sizes. See the manual for details.
Add configuration parameters grid.dx and grid.dy (command line options -dx and -dy). These parameters allow users to set the domain size and location (using the input file, grid.file or grid.Lx and grid.Ly) and then select the grid resolution to use on this domain. Note that grid.dx and grid.dy are in meters, but PISM will automatically convert to meters from units specified using command line options, e.g. -dx 5km. Domain half widths Lx and Ly are re-computed to ensure that PISM uses exactly the requested grid resolution (this may slightly reduce the domain size compared to Lx and Ly provided by the user).
Remove support for NCAR's ParallelIO library since (as far as we know) no one uses it.

MPI-GEA: PhD position on the interaction of ice sheets, ocean and sea level

2024-10-08T00:00:00+00:00

In the department of Integrative Earth system science at the newly founded Max Planck Institute of Geoanthropology (MPI-GEA) in Jena, Germany, we are providing a three-year PhD position as part of the DFG priority program “Antarctic Research with Comparative Investigations in Arctic Ice Areas”.

We are looking for a highly motivated candidate, interested in working in an interdisciplinary research team, with a focus on the interaction and possible feedbacks between the Greenland and Antarctic ice sheets via the Meridional Overturning Circulation (AMOC) and relative sea-level change in a warming climate. Numerical model simulations with PISM coupled to the global solid Earth and sea level model VILMA and the ocean model MOM will be used to investigate tipping characteristics and potential inter-hemispheric effects.

The position will start on 01 January 2025 or as soon as possible afterwards. Application deadline: 03 November 2024 Detailed information: https://bit.ly/3TRs5eP If you have any questions about the vacancy or require further information, please contact: albrecht@gea.mpg.de

PIK Potsdam: PostDoc positions in ice sheet and Earth system modelling

2024-08-21T00:00:00+00:00

A two-year PostDoc positions in ice sheet and Earth system modelling is available in the Ice Dynamics group, as part of the new Earth Resilience Science Unit (ERSU), at the Potsdam Institute for Climate Impact Research (PIK).

The position is part of the German Climate Modeling Initiative PalMod III, with focus on the interaction and possible feedbacks of the Antarctic Ice Sheet with the solid Earth, the global sea level and the climate. Simulations will be performed with the Parallel Ice Sheet Model (PISM) coupled to the global solid Earth and sea level model VILMA, to investigate tipping characteristics and potential interhemispheric interactions, in cooperation with ESM modelers within PalMod (CLIMBER-X, MPI-ESM, AWI-ESM, CESM).

The position will start on 01/10/2024 or as soon as possible afterwards. Application deadline: 31 August 2024 ! Detailed information: https://t1p.de/cwp18 If you have any questions about the vacancy or require further information, please contact: albrecht@pik-potsdam.de

U Copenhagen: 2 PhD positions in ice sheet modelling at the Niels Bohr Institute

2024-08-16T00:00:00+00:00

Two PhD fellowship positions in ice sheet modelling are advertised at the Niels Bohr Institute, University of Copenhagen.

One is in stability and tipping points of ice sheets in the Earth system, with a specific PISM connection. This PhD is a collaboration between the Niels Bohr Institute and the Danish Meteorological Institute. Application deadline: 25 August 2024. Read more and apply here: jobportal.ku.dk/phd/?show=162276

The second is a PhD fellowship in computational and mathematical modelling of flow and fracture in ice sheets. This PhD is part of the Novo Nordic Foundation project PRECISE – Predicting Changes in Ice Sheets on Earth. Application deadline: 1 September 2024. Read more and apply here: jobportal.ku.dk/phd/?show=162378.

AWI Bremerhaven: PhD position Projections of future sea-level rise from coupled ice sheet-ocean modelling

2024-08-07T00:00:00+00:00

The Alfred Wegener Institute, Bremerhaven, is offering a PhD position in the field of coupled ice sheet-ocean modelling. The core of the project is to run simulations with FESOM-PISM (a coupled ocean-ice shelf-ice sheet model with evolving cavity geometries) for different 21st-century climate projections to obtain well-constrained trajectories of future ice mass loss from the vast Antarctic Ice Sheet. Model results will feed into a fingerprinting method that considers the ocean response as well as gravitational effects and contributions from other sources. The final product will be a time series of global maps of regional sea-level variations that consider all of the most relevant processes.

The full announcement can be found here

jobs.awi.de/Vacancies/1768/Description/2

Closing date for applications is the 30th of August, 2024. (not the 31st!)

MARUM Bremen: open postdoc in ice-sheet modeling

2024-06-05T00:00:00+00:00

MARUM - Center for Marine Environmental Sciences at the University of Bremen is offering a position for one postdoctoral researcher in ice-sheet modeling, in the project “PalMod III-From the Last Interglacial to the Anthropocene”.

https://www.geo.uni-bremen.de/geomod/staff/mprange/open_position_MARUM.pdf

!!!THE DEADLINE FOR APPLICATIONS HAS BEEN EXTENDED TO JUNE 30th, 2024!!!

Please submit your application documents until June 30th, 2024 to Matthias Prange (mprange@marum.de).

PISM 2.1 is out

2023-11-27T00:00:00+00:00

We are pleased to announce the release of PISM v2.1.

Notable changes compared to v2.0

Some of these were included in 2.0.x bug fix releases.

Mass transport

Added a flux limiter that ensures strict preservation of non-negativity of ice thickness and therefore mass conservation up to rounding error.

This is a Zalesak-style limiter described in

P. K. Smolarkiewicz, “Comment on “A Positive Definite Advection Scheme Obtained by Nonlinear Renormalization of the Advective Fluxes”,” Monthly Weather Review, vol. 117, no. 11, pp. 2626–2632, 1989, doi: 10.1175/1520-0493(1989)117<2626:COPDAS>2.0.CO;2.

Note that this approach (unlike modifications of the discretization of SIA diffusivity in the Jarosch et al. paper mentioned below) works with all stress balance models.
Implemented a benchmark verifying mass conservation in an “isothermal SIA + mass continuity” setup with “rough” bed topography.

This benchmark is described in

A. H. Jarosch, C. G. Schoof, and F. S. Anslow, “Restoring mass conservation to shallow ice flow models over complex terrain,” The Cryosphere, vol. 7, no. 1, pp. 229–240, Feb. 2013, doi: 10.5194/tc-7-229-2013.

Isochrone tracing

Implemented an isochronal layer tracing scheme (see A. Born and A. Robinson, “Modeling the Greenland englacial stratigraphy,” The Cryosphere, vol. 15, no. 9, pp. 4539-4556, 2021, doi: 10.5194/tc-15-4539-2021.)

Surface processes

Implemented the diurnal energy balance model dEBM-simple (see M. Zeitz, R. Reese, J. Beckmann, U. Krebs-Kanzow, and R. Winkelmann, “Impact of the melt-albedo feedback on the future evolution of the Greenland Ice Sheet with PISM-dEBM-simple,” The Cryosphere, vol. 15, no. 12, pp. 5739-5764, Dec. 2021, doi: 10.5194/tc-15-5739-2021.)

Atmosphere forcing

Added support for 2D precipitation offsets in -atmosphere ...,delta_P. If the input file set using atmosphere.delta_P.file contains a scalar time series delta_P, use that as a time-dependent constant-in-space forcing. If the input file contains a 2D variable delta_P, use that as a time-and-space-dependent forcing.
Added support for 2D air temperature offsets in -atmosphere ...,delta_T. If the input file set using atmosphere.delta_T.file contains a scalar time series delta_T, use that as a time-dependent constant-in-space forcing. If the input file contains a 2D variable delta_T, use that as a time-and-space-dependent forcing.
Added support for piecewise-constant temporal interpolation of near-surface air temperatures in -atmosphere given: set atmosphere.given.air_temperature_interpolation to piecewise_constant.

Ocean forcing

Added the ability to use ocean model components implemented in Python (see examples/python/pism.py)

Calving

Fixed a bug reported by Christian Rodehacke: calving mechanisms should not remove ice at ice fronts adjacent to isolated patches of ice-free water (see issue #521).

Stress balance

Improved the initial guess of sliding velocity used when the ice front advances by extrapolating velocity computed by the SSAFD solver during the previous time step (set stress_balance.ssa.fd.extrapolate_at_margins to false to disable).

Energy conservation

PISM no longer attempts to correct energy conservation by freezing basal water.

At each time step PISM checks basal enthalpy and if necessary modifies it to ensure continuity of temperature in each bedrock+ice column. Sometimes this modification creates energy; prior to this change PISM attempted to remove an equivalent amount of energy by modifying the basal melt rate to freeze water stored at the base.

Under some conditions this basal melt rate adjustment created mass by freezing more water than available and even led to crashes with error messages stating that ice thickness exceeds Lz.

Input and output, diagnostics

Added diagnostics tendency_of_ice_{amount,mass}_due_to_frontal_melt and tendency_of_ice_{amount,mass}_due_to_forced_retreat. Renamed diagnostic max_sliding_vel to max_horizontal_vel.

Bug fixes

Added time bounds to scalar forcing files in examples/std-greenland.
Fixed a bug in the code ensuring non-negativity of ice thickness. (The old code added too much ice in an attempt to ensure non-negativity – so much so that sometimes this caused crashes with error messages stating that ice thickness exceeds Lz.)

Note that this “projection step” (ice_thickness = max(tentative_ice_thickness, 0)) should have no effect now: the flux limiter mentioned above is designed to ensure non-negativity. We keep this step, however, to maintain the ability to keep track of ice thickness changes due to conservation errors (if they ever happen).
Fixed bugs in scalar diagnostics ice_volume_cold and ice_volume_temperate.
Use CF-compliant units “common_years” in forcing files.

Other

Added CITATION.cff to properly acknowledge all contributions and to make it easier to cite PISM.
Implemented UNO2, UNO3 and a couple of related transport methods (not used, but available for future use; see J.-G. Li, “Upstream Nonoscillatory Advection Schemes,” Monthly Weather Review, vol. 136, no. 12, pp. 4709-4729, Dec. 2008, doi: 10.1175/2008mwr2451.1.).
Use realpath() to resolve relative file names. Now configuration parameters ending in .file, when saved to output files and in PISM output to stdout, contain absolute file names. This will make it easier to reproduce runs based on an output file.
Added support for checkpointing the HTCondor way (see commit 3740c41df).
Use -list_diagnostics all to print the list of all diagnostics, -list_diagnostics spatial for 2D and 3D variables, and -list_diagnostics scalar for scalar time series.
Added code to generate pism.pc and pismicebin.pc for use with pkg-config. This will make it easier to use PISM as a library (to couple to a GCM, for example).
PISM’s build system uses pkg-config to look for some of the required libraries.
Refactored utility classes used to store 2D and 3D arrays.
Replaced examples/searise-antarctica with examples/antarctica based on ALBMAP v1 data. This avoids a dependency on SeaRISE data formerly hosted by the University of Montana.

Congrats to Constantine

2023-05-01T00:00:00+00:00

Dear PISM users and developers

It’s my pleasure to congratulate our software engineer and PISM mastermind Constatine Khroulev to the birth of his son, Alexander (Sasha). Constantine is now on paternity leave and hence I’d like to ask for your patience as answering PISM questions will take longer in the next couple months.

Thank you for your understanding,

Andy

Joint GEUS-PIK workshop October 24-25, 2022

2022-10-26T00:00:00+00:00

Group photo in front of GEUS.

Nanna Karlsson and Liam Colgan hosted the first joint GEUS-PIK PISM workshop at GEUS in Copenhagen, DK, October 24-25, 2022.

Ricarda Winkelmann (PIK) introducing the concept of tipping points

Over 15 reseachers from GEUS, PIK, Aarhus University, DMI and UAF attendend the first joint GEUS-PIK PISM workshop at GEUS. The participants presented their latest PISM and PISM-adjacent research interspersed with lively discussions which data sets could be used for model initialization, calibrations and validation, how can we detect tipping points, what are the best practices to initialize PISM, and which physical processes are currently missing. The discussions continued during a visit to the GEUS roof where Nanna showed us the GEUS weather station and during the workshop dinner. Many started dreaming about joining field work in Greenland some day.

We are all already looking forward to the next joint workshop currently planned for October 2023.

Thank you Liam and Nanna for organizing and hosting the workshop.

Group dinner Monday evening