Sensitivity of Arctic Ocean Change to Background Mixing
This project is motivated by recent findings showing the sensitivity of Arctic Ocean circulation to background deep-ocean diapycnal mixing. Mixing in the stratified ocean is related to internal wave energy, which tends to be low under the Arctic Ocean ice cover. Consequently, as ice cover declines background mixing may increase and, among other changes, bring more Atlantic Water heat to the surface to melt ice, a potentially important positive climate feedback. To understand the influence of background mixing and to improve models of the changing Arctic Ocean, we are taking advantage of the latest analysis techniques to examine existing internal wave and mixing data and thereby developing a database tracking changes in the internal wave and mixing environments. We are combining recent observations and ice model results with existing, but heretofore untested, ideas to explore the energetics of Arctic internal waves and mixing under changing ice conditions. We are incorporating these findings into an ice-ocean model to explore the sensitivity of ocean circulation, heat flux and freshwater balance to possible changes in mixing.
By running the improved model, we will determine whether increased mixing due to decreased ice cover constitutes a positive climate feedback.