The stepwise decrease of 4+ year ice extent and its linked survivability since around 2007

• Published in: Journal of Glaciology
• Main Authors: Shan, Qi, Fan, Ke, Liu, Jiping
• Other Authors: National Key Research and Development Program of China
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2024
• Subjects: Arctic; Fram Strait; Journal of Glaciology; Sea ice
• Online Access: http://dx.doi.org/10.1017/jog.2024.33; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022143024000339

Abstract Recent studies have reported a shift in the Arctic sea ice to a younger state after around 2007. This study reveals that this shift can be primarily attributed to a stepwise-type reduction in the extent of 4 years or older (4+ year) ice and its linked survivability. After this shift, the fraction of 4+ year ice extent relative to the total ice changed from 30.5 to 10.0%. Sea-ice survivability can serve as a key indicator of sea-ice persistence in response to other factors. We demonstrate that the decrease of 4+ year ice is controlled by the decrease of its linked survivability in a non-linear manner, signifying small alterations in the survivability can result in relatively large changes in the extent of 4+ year ice. The decrease in survivability is affected by both winter and summer processes. Summer melting contributed the most, while the contribution of the export through Fram Strait was minor. However, the significant rise in residual loss during the growth season suggests that other winter processes may also have played an important role.