Arctic Sea Ice Decline Preconditions Events of Anomalously Low Sea Ice Volume Export Through Fram Strait in the Early 21st Century

Abstract

AbstractUnderstanding the changes of Fram Strait sea ice volume export and responsible processes is crucial due to their climate relevance. In this paper, we disentangled the processes driving the interannual variability and trends of the Fram Strait sea ice volume export in the early 21st century (2001–2019) by using dedicated numerical simulations with the support of observations. The significant decreasing trend in the sea ice volume export is caused by the persistent thinning trend of Arctic sea ice, while the interannual variability of the volume export is predominantly determined by winds. The interannual variability of the volume export can be mainly attributed to the variation in sea ice drift at Fram Strait, while the variation in Fram Strait sea ice thickness also plays an important role. As a result, the atmospheric mode that can better represent the wind variability driving the variability of both the sea ice drift and thickness at Fram Strait can better explain the variability of the sea ice volume export. The wintertime Arctic Oscillation (AO) and Fram Strait sea ice volume export continue to have a strong linkage in the early 21st century. The persistent thinning of Arctic sea ice preconditions events of anomalously low Fram Strait sea ice volume export. One of the extreme events in recent years occurred in 2017/2018. Variation in winds alone would not have caused such an extreme event without the persistent Arctic sea ice thinning.