Assessing the long-term dynamics and stability of Arctic ice shelves with periodic roll structure

The breakup and drift of multiyear landfast sea ice from the Arctic triggered several episodes of abrupt climate change (including deglacial cooling periods, Condron et al., 2020) after the end of the Last Glacial Period (LGP). Though most of this sea ice disintegrated during deglaciation, the few ice shelves that remain in the Arctic exhibit one common feature: large rolls on the surface of the ice. Using physical models, we have shown that the vibrational modes of such ice shelves contain band gaps in the frequency domain, implying that these ice shelves prevent ambient ocean sea swell waves of certain frequencies from flexing and breaking the ice. Based on these findings, we create a stochastic model of ice shelf decay due to random calving events whose probability is modulated by the presence of surface rolls. We examine fluctuations in ice extent on the millennial scale timespan since the LGP, also accounting for the growth of the ice shelf by snow accumulation and lateral addition of marine ice. In the presence of the same external factors, ice shelves with surface rolls are more likely to achieve a stable mass-balance while ice shelves without these features are eventually driven into extinction. This model demonstrates that certain ice shelves have a historical “fitness” for survival which is important for understanding the interaction between ice and climate.

Condron, A., Joyce, A. J., Bradley, R. S. (2020). Arctic sea ice export as a driver of deglacial climate. Geology, 48 (4): 395–399.