Co-leads: Gunilla Svensson (Stockholm University, Sweden) and Markus Jochum (University of Copenhagen, Denmark).

This theme, focusing on model error, will initially concentrate on two goals: (a) to determine what processes in GCMs contribute most to error growth on hourly to seasonal time scales and seasonal to interannual time scales in the polar regions, and (b) to develop observational and modelling strategies to improve these processes. The current understanding is that the processes contributing to model error are the same over all these timescales when focusing on the atmosphere, ocean and sea-ice physics.

As a starting point for discussion, we have identified the following processes:
•    representation of Arctic storms
•    evolution and radiative properties of Arctic clouds
•    sea-ice albedo
•    boundary layer turbulence in the atmosphere
•    ocean mixed layer heat budget
•    riverine freshwater, coastal currents, and vertical mixing
•    Atlantic Layer water inflow and subsequent diffusion

This initial list will be discussed with colleagues and will hence be modified. We will convene a meeting in the fall/early winter. Goals of the meeting are:

1) to bring together people that are currently without new additional resources to conduct research on the processes identified above.
2) b) from above.

We anticipate a number of smaller working groups to focus on sub-parts of the problem and continue to feed into the planning of the observations and developing activities, such as the Year of Polar Prediction (YOPP) of the Polar Prediction Project.