Processes in the Arctic

The Danish Climate Centre (DKC) has a long tradition of studying and modelling processes in the Arctic. With DKC’s regional climate model, HIRHAM, many simulations of the Arctic have been conducted, and until now (2011), HIRHAM is the only regional climate model that has been applied covering the whole circumpolar domain north of approximately 60°N.

Future climate change is expected to be larger in the Arctic than almost everywhere else on the globe. It is therefore important to assess potential future changes, using climate models. At the same time, arctic climate is less constrained in models than is the case for most other regions. That is because of the inherent nonlinearity of the arctic climate system (with huge changes at the freezing point), but also due to the fact that there are many unknowns in the model world.

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

Permafrost research

An important component of the cryosphere is permafrost. The DKC plays a prominent role in permafrost research, and through multifaceted collaboration we seek to bridge the gap between local field studies on one side and circumpolar model assessments on the other.

In close cooperation with scientists from Greenland, Sweden, Norway, Germany, the USA and Russia, the DKC addresses aspects of changes in permafrost. For this approach, very high resolution regional climate model simulations are necessary, and the DMI has pioneered this approach by conducting simulations at the unprecedented resolution of 4 km. Detailed high resolution assessments of changes in permafrost have been made for several regions in Russia, Alaska and Greenland.

 
Temperatures at 2 m depth. Blue areas are permafrost, while red areas denote thawing permafrost or seasonally frozen soil. Data from a 4 km x 4 km HIRHAM5 run over north-eastern European Russia. Conducted at the DKC in the framework of the Carbo-North project and used to drive a dedicated permafrost model (GIPL-2, University of Alaska Fairbanks) at the same resolution. For 1980-1999 (left) and 2080-2099 (right), scenario A1B. Figure courtesy: Sergei Marchenko, University of Alaska Fairbanks

The high resolution output of HIRHAM is used to drive a dedicated permafrost model, GIPL from the University of Fairbanks. In addition, there are also several initiatives aiming to add a permafrost module to the HIRHAM model. Recent results show that large amounts of greenhouse gases (carbon dioxide and methane) from partly decomposed organic material might be released if the frozen ground thaws.

Versatile model development

The DKC has frequently addressed deficiencies in understanding climate processes in the Arctic, for example in the EU-supported project GLIMPSE. Minor changes in the parameterization of arctic processes and feedbacks in HIRHAM, for example the albedo of thawing sea ice and the treatment of snow on canopies, have profound effects not only on the Arctic, but also on large parts of Europe.

The flexible model setup with HIRHAM makes it possible to test hypotheses, for example the connection of record-low ice in the Barents and Kara Seas to cold winters over Central Europe.

We are also participating in a number of initiatives aimed at improving deficiencies in model setup and involving early career scientists.

Contacts

For further information contact Martin Stendel, mas@dmi.dk
Phone: (+45) 39157 446