98 Multi-Scale Response of Moisture Flux to Projected Sea Ice Loss

Tuesday, 27 June 2017
Salon A-E (Marriott Portland Downtown Waterfront)
Marie C. McGraw, Colorado State University, Fort Collins, CO; and C. F. Baggett, C. Liu, B. D. Mundhenk, and E. A. Barnes

An expanding body of research emphasizes the relationship between moisture transport into the Arctic and subsequent sea ice loss as an important component of Arctic and global climate change. Here, we isolate and quantify the impacts of projected Arctic sea ice loss on moisture flux into and out of the Arctic. Output from two simulations of the fourth version of the Community Atmosphere Model (CAM4) are used: a control run with surface boundary conditions fixed at late twentieth century values and a perturbed run with Arctic sea ice prescribed at projected late twenty-first century values. Differences between the two simulations isolate the impacts of future sea ice loss on the atmosphere. We demonstrate that the poleward component of moisture flux into the Arctic increases in the perturbed run. However, the equatorward component out of the Arctic increases more, yielding a net reduction in total moisture flux into the Arctic. Somewhat paradoxically, we also find a decrease in total eddy activity at high latitudes. To reconcile these results, we decompose the moisture flux and eddy activity across temporal and spatial scales - ranging from lower-frequency, planetary-scale structures to higher-frequency, plume-like atmospheric rivers - and find contrasting and competing changes. These results are framed in the context of changes in the storm tracks, Rossby wave breaking behavior, and large-scale dynamics. Finally, we further present how these changes feed back upon the Arctic climate itself.

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