The Arctic is rapidly losing its oldest, thickest multiyear sea ice and transitioning to a predominantly first-year ice cover. Improving our knowledge of the variability of Arctic sea ice is crucial for better understanding changes in the global climate system. The ongoing loss of Arctic sea ice has serious implications for Earth’s climate, including impacts on Earth's energy budget, the overturning of global ocean thermohaline circulation and changes in mid-latitude weather. Widespread economic, ecological and societal impacts of a declining ice cover on the Arctic region are already evident including increases in shipping, coastal erosion and changes in fish and wildlife habitats.

Kyle Duncan, a researcher with the Earth System Science Interdisciplinary Center, and Dr. Sinead L. Farrell, Associate Professor in the Department of Geographical Sciences, have used measurements of sea ice topography obtained from NASA's ICESat-2 satellite laser altimeter to map deformation in the Arctic sea ice cover. The high resolution observations from ICESat-2 can be used to detect individual pressure ridges across the Arctic sea ice cover. From this the scientists derived metrics to describe the roughness of sea ice and the intensity of ice ridging across the Arctic Ocean. Consistent with previous studies they found that sea ice deformation across the Arctic Ocean in winter is much more prevalent in multiyear ice than in seasonal ice. Their results also showed however that deformation varies not only with ice regime, but also geographic location. Ice deformation was greatest along the Arctic land boundaries of the multiyear ice zone and was a factor of two larger than the deformation characteristics of multiyear ice at more northerly latitudes near the North Pole. Localized deformation in the seasonal ice zone, due to convergence against a static boundary, can result in areas with deformation commensurate with that found in multiyear ice. These new observations provide metrics that may ultimately be used to improve sea ice model simulations. The ongoing availability of ICESat-2 observations means regional sea ice deformation events and seasonal variability can be monitored year-round in the future.

Read the study here.