A Mechanism for the Arctic Sea Ice Spring Predictability Barrier
A Mechanism for the Arctic Sea Ice Spring Predictability Barrier
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DOI：
10.1029/2020gl088335
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发表时间：
2020-07-16
影响因子：
5.2
通讯作者：
Delworth, Thomas L.
中科院分区：
文献类型：
--
作者：
Bushuk, Mitchell;Winton, Michael;Delworth, Thomas L.
北极海冰范围的减少迫切需要对区域夏季海冰进行准确的季节性预测。最近的研究表明，北极海冰春季可预测性障碍的证据，这可能会对春季之前开始的区域预测施加严格的限制。然而，这种屏障的物理机制仍然难以捉摸。在这项工作中，我们进行了每日海冰质量（SIM）预算分析大型合奏实验从两个全球气候模式调查的机制，支撑春季可预测性障碍。我们发现，可预测性是有限的，在冬季的天气驱动SIM出口和海冰增长的负反馈。春季障碍的结果从一个急剧增加的可预测性在融化开始时，冰-水反馈作用，以加强和坚持预先存在的出口产生的质量异常。这些结果意味着，融化开始后收集的冰厚观测夏季北极海冰的预测是特别重要的。
The decline of Arctic sea ice extent has created a pressing need for accurate seasonal predictions of regional summer sea ice. Recent work has shown evidence for an Arctic sea ice spring predictability barrier, which may impose a sharp limit on regional forecasts initialized prior to spring. However, the physical mechanism for this barrier has remained elusive. In this work, we perform a daily sea ice mass (SIM) budget analysis in large ensemble experiments from two global climate models to investigate the mechanisms that underpin the spring predictability barrier. We find that predictability is limited in winter months by synoptically driven SIM export and negative feedbacks from sea ice growth. The spring barrier results from a sharp increase in predictability at melt onset, when ice-albedo feedbacks act to enhance and persist the preexisting export-generated mass anomaly. These results imply that ice thickness observations collected after melt onset are particularly critical for summer Arctic sea ice predictions.