Atmospheric Warming Drives Growth in Arctic Sea Ice: A Key Role for Snow.
Atmospheric Warming Drives Growth in Arctic Sea Ice: A Key Role for Snow.
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DOI：
10.1029/2020gl090236
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发表时间：
2020-10-28
影响因子：
5.2
通讯作者：
Heimbach P
中科院分区：
文献类型：
--
作者：
Bigdeli A;Nguyen AT;Pillar HR;Ocaña V;Heimbach P
一些反馈调节北极海冰对当地大气变暖的反应。使用一个现实的耦合海洋海冰模型及其伴随，我们隔离的机制，显着的冰增长在融化季节结束时可能会发生作为一个滞后的响应北极大气变暖。一系列由伴随模型导出的敏感性模式提供信息的扰动模拟揭示了冰层生长的增强伴随着冰层上积雪厚度的减少。对海洋-冰雪热量收支的详细分析证实了积雪厚度的减少对冰增长的持续性和延迟超调的重要作用。潜在的机制是雪融化传导反馈，其中大气驱动的雪融化导致通过覆盖冰层的更大的传导性海洋热损失。我们的研究结果强调了需要精确观测积雪厚度来约束气候模型和初始化海冰预测。北极海冰对大气变暖的敏感性是使用数值伴随计算的，揭示了变暖可能导致海冰增长滞后。作为对早期变暖的响应，积雪融化是关键的预条件，使大量的海洋热传导损失能够支持滞后的海冰增长。
A number of feedbacks regulate the response of Arctic sea ice to local atmospheric warming. Using a realistic coupled ocean‐sea ice model and its adjoint, we isolate a mechanism by which significant ice growth at the end of the melt season may occur as a lagged response to Arctic atmospheric warming. A series of perturbation simulations informed by adjoint model‐derived sensitivity patterns reveal the enhanced ice growth to be accompanied by a reduction of snow thickness on the ice pack. Detailed analysis of ocean‐ice‐snow heat budgets confirms the essential role of the reduced snow thickness for persistence and delayed overshoot of ice growth. The underlying mechanism is a snow‐melt‐conductivity feedback, wherein atmosphere‐driven snow melt leads to a larger conductive ocean heat loss through the overlying ice layer. Our results highlight the need for accurate observations of snow thickness to constrain climate models and to initialize sea ice forecasts. Arctic sea ice sensitivity to atmospheric warming is computed using a numerical adjoint, revealing warming can lead to lagged sea ice growth Snow melt—in response to early warming—is the key preconditioner, enabling large conductive ocean heat loss to support lagged ice growth