Ice Sheet Modelling

The Arctic is a highly prioritized research area at the Danish Climate Centre (DKC). Long-range global climate change is expected to first appear in the Polar Regions. In the past decade, notable reductions in the extent and thickness of the Greenland Ice Sheet have been observed. Satellite observations show that mass loss of the ice sheet is increasing each year and more rapidly than predicted.

The climate processes in the Arctic need to be better understood to predict future sea-level rise. In close collaboration with national and international partners, DKC is developing distinct Arctic projection models that will improve the accuracy of predictions on how the ice sheet will evolve in the future, and how it will interact with the atmosphere and the ocean.

Focus areas

Regional Climate Modelling

Global Climate Modelling

Ozone, UVR and Climate

Radio Occultations

Ice Sheet Modelling

Processes in the Arctic

Developing Countries

Climate Data Host

Model coupling

At the DKC, we develop complex projections of the ice sheet development. We couple our regional and global climate models to the three dimensional thermomechanical ice sheet model, PISM, which is actively developed at the University of Alaska Fairbanks and can simulate spatially and temporally varying ice streams.

Both the regional climate model HIRHAM5 and the Earth System Model EC-Earth have been upgraded to include energy balance modelling at the ice sheet surface to compute snow and ice melt. In addition, a new snow model with a number of snow processes such as melt water percolation and refreezing is being implemented. These components of the mass budget, together with the precipitation, constitute the surface mass balance of the ice sheet. Both models are coupled to the ice sheet model in a similar way.

The coupled model systems are used to compute the surface mass balance of the Greenland ice sheet in the recent past and to project its sensitivity to different greenhouse gas scenarios.

Model coupling. As the projected sea level rise is not expected to be uniformly distributed, it is necessary to base both regional and local projections on global coupled simulations to predict local sea level rise

Our aim is to develop a fully interactive ice sheet model that responds to climate variations and feeds information about the runoff from the melting processes into the Earth Simulation Model or ocean model to close the water circle. Ice sheet model developments and the development of coupling of the ice sheet and climate models is done in collaboration with the University of Alaska, Fairbanks.

Present day ice sheet projections from the fully coupled systems are also analysed and compared with satellite data and ground-based measurements from Greenland to validate their accuracy.

Arctic research projects

DKC is involved in several international research projects within this area and supplies analyses and climate projections. In addition, DKC acts as host for data of Arctic climate projections.

Modelled components of the mass budget for the Greenland ice sheet for the period 1989-2009. From HIRHAM5 run on 25 km resolution forced by the ERA-Interim reanalysis product

The EU-supported Ice2sea is a comprehensive European research project that produces 200-year projections of the contribution to global sea-level rise from continental glaciers and ice sheets. Ice2sea will provide input for the fifth IPCC assessment report, which is due in 2013.

The COMBINE project employs earth system models to assess climate changes and their impacts to society and economic systems. DKC is leading the theme on incorporating polar ice-sheets, sea-ice and permafrost into earth system models.

Future projection of the total mass budget components of the Greenland ice sheet for the period 1980-2100. The regional model HIRHAM5 is forced with the global model ECHAM5 in this model computation applying the A1B scenario

Results from the comprehensive earth system models will provide input to the IPCC/AR5 process. The data will be used to test the underlying assumptions in the scenarios, and hence contribute to improved scenarios.

The SVALI project is a Nordic collaborative study of how fast land ice volume in the Arctic and North-Atlantic area is changing and why. DKC and Nordic partners also examine whether the processes will continue to accelerate and look into the consequences for sea-level and ocean circulation and the implications to society.

The FreshNor project was supported by the Nordic Council of Ministers' Arctic Co-operation Programme, and worked towards an improved understanding of the fresh water cycle in the Nordic Seas. FreshNor was coordinated by DKC.

Collaboration and field work in Greenland

The DKC cooperates closely with a number of national and international research institutes in Greenland. We develop and produce climate projections for a number of different projects.

In collaboration with the Greenland Climate Research Centre in Nuuk we develop projections to help generate a better understanding of future climate change and improve preparedness in the Arctic region.

In 2007, the Danish Ministry of Climate and Energy launched the Programme for Monitoring of the Greenland Ice Sheet, PROMICE as an ongoing effort to assess changes in the mass budget of the Greenland Ice Sheet.

One of the PROMICE Weather stations located on the east coast of Greenland, close to the village of Isortoq. Photo: Gudfinna Adalgeirsdottir

PROMICE is operated by the Geological Survey of Denmark and Greenland, GEUS in collaboration with the National Space Institute, DTU Space and the Greenland Survey (Asiaq).

The National Space Institute, DTU Space processes and analyses satellite data that yield information about the current changes of the Greenland Ice Sheet.

Data to validate and constrain the models and projections are important. The Centre of Ice and Climate at the Niels Bohr Institute, University of Copenhagen drill ice cores from the Greenland ice sheet that give information that helps understanding past and future climate.

With Greenland Climate we are also participating in the research project Regional Climate Change in Greenland and Surrounding Seas. The aim is to establish a data and knowledge base on the expected climate change in the Arctic, and provide a foundation for studying the specific impact of climate change on the marine environment in details.

Contacts

For further information contact Ruth Mottram, rum@dmi.dk
Phone: (+45) 39157 488