Fingerprints of internal drivers of Arctic sea ice loss in observations and model simulations
Fingerprints of internal drivers of Arctic sea ice loss in observations and model simulations
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DOI：
10.1038/s41561-018-0256-8
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发表时间：
2019-01-01
影响因子：
18.3
通讯作者：
Baxter, Ian
中科院分区：
文献类型：
--
作者：
Ding, Qinghua;Schweiger, Axel;Baxter, Ian
最近北极海冰损失的内部变率的相对贡献和物理驱动因素仍然是悬而未决的问题，用于气候预测的全球气候模型是否在北极对气候强迫缺乏足够的敏感性仍有待讨论。在这里，通过分析大量的完全耦合的气候模式模拟与历史辐射强迫，我们提出了一个重要的内部机制所产生的低频北极大气变率的模型，可以导致大量的夏季海冰融化，除了由于人为强迫。这种模拟的内部变率与过去37年观测到的北极大气变化有很强的相似性。通过指纹模式匹配的方法，我们估计，这种内部的变化有助于约40-50%的观测到的几十年来减少北极海冰。我们的研究还表明，全球气候模型实际上可能并没有低估北极海冰的敏感性，但很难完全复制近几十年来观察到的北极和低纬度地区之间的联系。因此，在模型中北极对全球变暖的敏感性可以有信心地量化之前，有必要进一步改进对所观察到的北极-全球联系的模拟。
The relative contribution and physical drivers of internal variability in recent Arctic sea ice loss remain open questions, leaving up for debate whether global climate models used for climate projection lack sufficient sensitivity in the Arctic to climate forcing. Here, through analysis of large ensembles of fully coupled climate model simulations with historical radiative forcing, we present an important internal mechanism arising from low-frequency Arctic atmospheric variability in models that can cause substantial summer sea ice melting in addition to that due to anthropogenic forcing. This simulated internal variability shows a strong similarity to the observed Arctic atmospheric change in the past 37 years. Through a fingerprint pattern matching method, we estimate that this internal variability contributes to about 40-50% of observed multi-decadal decline in Arctic sea ice. Our study also suggests that global climate models may not actually underestimate sea ice sensitivities in the Arctic, but have trouble fully replicating an observed linkage between the Arctic and lower latitudes in recent decades. Further improvements in simulating the observed Arctic-global linkage are thus necessary before the Arctic's sensitivity to global warming in models can be quantified with confidence.