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

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...

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Bibliographic Details
Published in:Journal of Glaciology
Main Authors: Qi Shan, Ke Fan, Jiping Liu
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press
Subjects:
Online Access:https://doi.org/10.1017/jog.2024.33
https://doaj.org/article/7bdea0447c4e4b009414abdf6c2117bb
Description
Summary: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.