Contributions of growth and deformation to monthly variability in sea ice thickness north of the coasts of Greenland and the Canadian Arctic Archipelago

Regional variability in monthly CryoSat-2 sea ice thickness is partitioned into contributions from dynamics and thermodynamics using ice deformation calculated from large-scale ice drift. For five winters (December to April, 2011-2015), over a region of persistent convergence north of the coasts of Greenland and the Canadian Arctic Archipelago, deformation explains similar to 34% of the overall variance (up to 69% in 2014/2015) in monthly thickness changes. Approximately 42-56% (or similar to 0.6m) of the seasonal changes in mean regional ice thickness can be attributed to divergence and shear. The estimated area-averaged growth of 0.120.03m/month compares favorably with measurements from ice mass balance buoys. Examination of the time-variable thickness distributions shows areas covered by ice <3m are reduced, while areas of thicker ice (>3m) increased. Albeit at fairly coarse resolution, this coupled analysis of thickness changes and deformation offered a first look at the character of the regional thickness redistribution process.