Contribution of ice dynamics along Nares Strait to the stability of ice arches

Abstract Nares Strait, situated between northwest Greenland and Ellesmere Island, is an important conduit for exporting sea ice from the Arctic, especially thick multi-year ice undergoing an accelerated loss compared to other ice types. This export is impacted by ice arches that can form along the Strait and remain stable for months at a time resulting in a reduction in ice export. Arch stability is a function of sea ice thickness and there is a concern that the thinning of Arctic sea ice may weaken the arches resulting in an accelerated export of sea ice. However, little is known about the spatial and temporal variability of sea ice thickness along the Strait. Here we show that before arch formation, there is a local maximum in ice thickness where arches typically form, which is related to ice convergence. Furthermore, we demonstrate that ice motion continues north of the arch after it forms, resulting in convergence and a dynamic thickening of the sea ice. We propose that, even though thinning ice is a cause for concern, the dynamics of sea ice transport along Nares Strait lead to localized thickening of sea ice that may contribute to continued arch formation and stability.