Interannual variability in Transpolar Drift summer sea ice thickness and potential impact of Atlantification

Abstract. Changes in Arctic sea ice thickness are the result of complex interactions dynamic and variable cover with atmosphere ocean. Most exiting Ocean does so through Fram Strait, which is why long-term measurements at end Transpolar Drift provide insight into integrated signals thermodynamic influences along pathways ice. We present an updated summer (July–August) time series extensive surveys carried out between 2001 2020. Overall, we see a more than 20 % thinning modal since 2001. A comparison this first preliminary results from international Multidisciplinary drifting Observatory for Study Climate (MOSAiC) shows that MOSAiC floe its wider vicinity consistent previous years Drift. By combining unique Lagrangian tracking tool, ICETrack, simple growth model, link observed interannual variability north Strait to increased drift speeds consequential variations age. also show influence upward-directed ocean heat flux eastern marginal zones, termed Atlantification, not only responsible around Laptev Sea but induced anomalies persist beyond Russian shelves potentially still measurable after year. With tendency towards even faster Drift, winter will have less compensate impact processes, such as on zone, increasingly be felt other parts sea-ice-covered Arctic.