A New State of Arctic Sea Ice Age and Motion

Arctic sea ice distribution has changed considerably over the last couple of decades. Sea ice extent record minimums have been observed in recent years, the distribution of ice age now heavily favors younger ice, and sea ice is likely thinning. This new state of the Arctic sea ice cover has several impacts, including effects on marine life, feedback on the warming of the ocean and atmosphere, and on the future evolution of the ice pack.

The shift in the state of the ice cover, from a pack dominated by older ice, to the current state of a pack with mostly young ice, impacts specific properties of the ice pack, and consequently the pack's response to the changing Arctic climate. For example, younger ice typically contains more numerous melt ponds during the melt season, resulting in a lower albedo. First-year ice is typically thinner and more fragile than multi-year ice, making it more susceptible to dynamic and thermodynamic forcing. Younger, thinner ice may move more quickly, as it is more responsive to changing surface winds than thicker ice, which is impacted more by ocean currents.

We examine 30+ years of sea ice age and motion to explicitly determine how the Arctic ice pack has transformed from one dominated by older thicker ice to a new state, where first-year ice is most prevalent. We note that some areas of the Arctic are completely devoid of older ice, allowing for a complete melt-out of ice during the summer. Furthermore, we investigate the change in sea ice motion, expecting that the ice has been moving faster on average, accelerating its export through the Fram Strait to further reduce Arctic summer sea ice coverage.