Impacts of an Intense Arctic Storm in August 2016 on Sea Ice Decline

Climate analysis has suggested an intensification of Arctic storm activities. Unusually intense storms have also been more frequently observed during recent decade, which have occurred in many times preceding extreme sea ice loss or surface warming events, and may suggest their important contributing role in rapid Arctic climate changes. However, the underlying physical processes and mechanisms have not been well investigated and understood. In this study, we examined how the storm impacts the state of and changes in sea ice and upper ocean by employing the in-situ observations onboard the icebreaking R/V Araon, which just exactly captured a long-lived, intense storm in August 2016. The results show that associated with this storm, a cold air advection occurred at the observational site, leading to a net sea ice surface cooling. However, the storm dynamically enhanced upper ocean mixing and induced an upwelling of Pacific-origin warm water due to the Ekman pumping effects. The changed ocean dynamics result in a noted upper ocean warming and, in turn, an increase in ocean-to-sea ice heat flux, larger than the net heat loss from the sea ice surface. As a consequence, sea ice decline accelerated.