The 2015 Autumn Ice-Edge Advance during the Sea State Field Campaign as Compared to Ongoing Variability and Trends in Atmosphere-Ice Interactions in the Chukchi and Beaufort Seas

Some of the fastest Arctic sea ice changes are happening during the transitional seasons in the Chukchi and Beaufort Seas as indicated by a much earlier (~49 days) ice-edge retreat in spring, followed by a much later (~43 days) ice-edge advance in autumn (based on satellite observations over 1979 to 2014). These seasonal sea ice trends are consistent with the expected seasonal feedbacks, e.g., an earlier spring break-up leads to increased solar ocean warming and accelerated sea ice retreat, while the additional solar heat gained by the ocean slows ice edge advance. In addition, the observed trend towards an overall thinner, more seasonal Arctic sea ice cover enhances the feedback: less latent energy is required to melt a thinner sea ice cover, thus making available more sensible energy to warm the ocean. The lengthening of the summer open water season and increasing fetch also means a longer, and possibly stronger, period of wind/wave forcing on the advancing sea ice cover and upper ocean, coupled with changes in upper ocean heat and freshwater content. Thus, one of the goals of the “Sea State and Boundary Layer Physics on the Emerging Arctic” program is to understand how surface waves and winds affect sea ice growth processes and consequently the timing of the autumn ice-edge advance in the Chukchi and Beaufort Seas. Here we provide regional context for ship-based observations acquired during the autumn Sea State field campaign in 2015 that included measurements of waves, ice growth processes, changes in upper ocean heat and freshwater content and atmospheric fluxes. Using satellite and reanalysis products of sea ice and winds, respectively, we examined how regional winds and atmosphere-ice interactions contributed to the spatial orientation and rate of ice-edge advance in the Chukchi and Beaufort Seas in 2015 and compared those observations to ship-based observations of winds and sea ice. This regional assessment is then placed within the context of long-term (1979-present) variability and trends in regional atmosphere-ice conditions.