Sea ice inertial oscillation magnitudes in the Arctic basin
1ISTerre, UMR – CNRS, UMR 5275, Université Joseph Fourier, Grenoble, France
2ISTerre, UMR – CNRS, Université de Savoie, Le Bourget du Lac, France
3LGGE, UMR – CNRS, Université Joseph Fourier, Grenoble, France
4LEGI, UMR – CNRS, Université Joseph Fourier, Grenoble, France
Abstract. An original method to quantify the amplitude of inertial motion of oceanic and ice drifters, through the introduction of a non-dimensional parameter M defined from a spectral analysis, is presented. A strong seasonal dependence of the magnitude of sea ice inertial oscillations is revealed, in agreement with the corresponding annual cycles of sea ice extent, concentration, thickness, advection velocity, and deformation rates. The spatial pattern of the magnitude of the sea ice inertial oscillations over the Arctic basin is also in agreement with the sea ice thickness and concentration patterns. This argues for a strong link between the magnitude of inertial motion on one hand, the dissipation of energy through mechanical processes, and the cohesiveness of the cover on the other hand. Finally, a significant pluri-annual evolution towards greater magnitudes of inertial oscillations in recent years, in both summer and winter, is reported, thus concomitant with reduced sea ice thickness, concentration and spatial extent.