Modelling of deformation and recrystallization microstructures in polar ice: FUMOPOLI/NUMOPOLI

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During the last decades, the flow of large ice sheets has become one of the greatest issues in Earth and planetary sciences. As for our own planet, knowledge of the deformation mechanisms of polar ice is of crucial importance to predict the flow of polar ice caps and hence their influence on the global climate. Seeing that laboratory experiments cannot reproduce the slow and everlasting flow of polar ice sheets, most of our understanding of natural ice deformation comes from microstructural analyses of ice cores. Indeed, the microstructures seen in ice cores are invaluable records of the past in-situ deformation, although the unraveling of this complex deformation history remains a challenge for glaciologists. New techniques of microstructural analysis now allow a much more detailed and extensive assessment of these microstructures than ever before. The aim of this project is to develop theoretical and experimental methods to quantify the information encrypted in the vast and unique collection of photomicrographs available at AWI of several firn and ice cores, and in particular of the EPICA-DML2 deep ice core. Our ultimate objective is a critical reassessment the role of grain boundary formation and migration in several aspects of the microstructure evolution: the fading memory of deformation records, the evolution of anisotropy and the in-situ deformation mechanisms that control the flow of ice sheets.