Description of task
A relationship between the differential ice motion and the ice thickness changes from AUV, helo EM and ULS will be examined. This analysis will provide novel and urgently needed knowledge of the mechanisms controlling open water production, compression of the ice pack, and production of thick ridged ice.
The results will have a direct impact on the physical description of sea ice in operational and climate models via better constraints and parameterization of the sea ice rheology and the sub-grid variability of sea ice deformation, concentration and thickness.
Two distinct in-situ seismological experiments, which will monitor brittle deformation at the 1km and the regional (100-500km) scales, will also be conducted. The aim is to study the fracturing and episodic, aseismic deformation of the sea ice cover and its relationship to the local ice thickness distribution. The first experiment will be a close-up study of deformation mechanisms of the ice cover at what are sub-grid scales for climate models. The second experiment will constitute a 2-year monitoring of large structures that accommodate most of the deformation induced by relative ice motion.
The multi-category sea-ice model HELMI (Haapala et. al. 2005), which is coupled to the MPI-OM1 global ocean model, is used for the modelling studies. The model will be validated with the observed ice motion, mean ice thickness and concentration, undeformed ice thickness, ice thickness distribution, and the fractions of thin, multi-year and ridged ice. Shortcomings of the modelled sea-ice evolution will be identified and new parameterization schemes developed in this core theme will be implemented in the model.
Statistical characteristics of sea-ice and ocean properties are calculated from the model simulations, and contributions of dynamic and thermodynamics effects are separated. In addition to decomposing source terms of the variability, we will decompose the variability caused by the polar cyclones and the variability caused by the change of the mean atmospheric/oceanic circulation.
