Driving Mechanisms of an Extreme Winter Sea Ice Breakup Event in the Beaufort Sea

Abstract

Arctic sea ice is thinning (Meier, 2017) in conjunction with the decrease in the area covered by thick multiyear ice (MYI) (Kwok, 2018), which is replaced by thinner first-year ice (FYI) that is more mobile and less dynamically stable (Rampal et al., 2009;J. Zhang et al., 2012). This makes the ice cover more vulnerable to intense winds breaking up the sea ice. In the Beaufort Sea in particular, the loss of MYI may contribute to the earlier onset of the melt season in recent years (Johnson & Eicken, 2016).When sea ice breaks up, it exposes the underlying warmer ocean within narrow, linear openings in the ice cover known as leads. This has important consequences for air-sea exchange, ocean eddy generation and dynamics, sea ice production, and Arctic Ocean properties in general (Cohanim et al., 2021;Graham et al., 2019;Nguyen et al., 2009), especially during the winter months when heat fluxes over sea ice are generally small (Andreas & Cash, 1999). In addition, breakup in winter weakens the ice cover, potentially preconditioning the minimum ice extent in summer (Y. Zhang et al., 2018;Babb et al., 2019) and thus creating a positive feedback to Arctic amplification (Dai et al., 2019). Therefore, extreme breakup events are of crucial interest for understanding the seasonal and long-term evolution of Arctic sea ice, which in turn affect weather, ecosystems, and local communities in polar regions and beyond (Forbes et al., 2016;Vihma, 2014).

New Insights Into Cyclone Impacts on Sea Ice in the Atlantic Sector of the Arctic Ocean in Winter

“…This indicates that local SIC conditions are a key factor for the changed impact of cyclones on sea ice and is in accordance with our previous findings (Section 3.2; Figures 1b and 1c). In addition, it can be assumed that also the decreasing ice thickness promotes increased cyclone impacts because a thinner ice cover is more susceptible to atmospheric and oceanic forcings (Rampal et al., 2009; Rheinlænder et al., 2022; Zhang et al., 2012).…”

Observational Perspectives on Beaufort Sea Ice Breakouts

“…Thanks to Jonathan Rheinlænder and Einar Ólason for sharing model output and information that furthered discussion started in Rheinlænder et al. (2022).…”

“…Based on their simulations, Rheinlænder et al. (2022) highlighted strong winds and thin ice as key factors for breakout and postulated increases in future breakout frequency as sea ice thins.…”

“…To our knowledge, this is the first time lead opening and subsequent breakout has been simulated with an accuracy that may allow synoptic forecasts suitable for predicting risk of fracturing during BS ice navigation. Based on their simulations, Rheinlaender et al ( 2022) highlighted strong winds and thin ice as key factors for breakout and postulated increases in future breakout frequency as sea ice thins.In this commentary of Rheinlaender et al (2022), we highlight the atmospheric synoptic conditions that drove the 2013 breakout and explain the relationship between anticyclone track and the formation of wide leads visible in satellite imagery. We put the 2013 breakout into the context of similar events observed over the satellite record, including years with thicker ice packs.…”

“…In this commentary of Rheinlaender et al (2022), we highlight the atmospheric synoptic conditions that drove the 2013 breakout and explain the relationship between anticyclone track and the formation of wide leads visible in satellite imagery. We put the 2013 breakout into the context of similar events observed over the satellite record, including years with thicker ice packs.…”