Interannual variability in Transpolar Drift summer sea ice thickness and potential impact of Atlantification
Interannual variability in Transpolar Drift summer sea ice thickness and potential impact of Atlantification
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DOI：
10.5194/tc-15-2575-2021
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发表时间：
2021-06-15
期刊：
影响因子：
5.2
通讯作者：
Haas, Christian
中科院分区：
文献类型：
--
作者：
Belter, H. Jakob;Krumpen, Thomas;Haas, Christian
北极海冰厚度的变化是动态变化的冰盖与大气和海洋复杂相互作用的结果。大多数海冰都是通过弗拉姆海峡离开北冰洋的，这就是为什么在跨极漂移结束时对冰厚度的长期测量可以深入了解沿北极海冰路径的热力学和动力学影响的综合信号。我们提供了 2001 年至 2020 年跨极漂移结束时进行的广泛冰厚度调查的更新夏季（7 月至 8 月）时间序列。总体而言，我们看到自 2001 年以来模态冰厚度减薄了 20% 以上。将该时间序列与国际北极气候研究多学科漂移观测站 (MOSAiC) 的第一个初步结果进行比较表明，MOSAiC 浮冰的模态夏季厚度及其更广泛的附近区域与前几年跨极漂移结束时的测量结果一致。通过将这一独特的时间序列与拉格朗日海冰跟踪工具 ICETrack 和简单的热力学海冰生长模型相结合，我们将观察到的弗拉姆海峡以北的年际冰厚度变化与沿跨极漂移的漂移速度增加以及随之而来的海冰年龄变化联系起来。我们还表明，东部边缘冰区向上的海洋热通量（称为“亚特兰化”）的影响不断增加，不仅导致拉普捷夫海及其周围的海冰变薄，而且还导致俄罗斯大陆架以外的地区持续存在厚度异常，并且在一年多后的跨极漂移结束时仍然可以测量到。由于跨极漂移有更快的趋势，冬季海冰生长将没有足够的时间来补偿亚特兰化等过程对东部边缘冰区海冰厚度的影响，而在海冰覆盖的北极其他地区，这种影响将越来越明显。
Changes in Arctic sea ice thickness are the result of complex interactions of the dynamic and variable ice cover with atmosphere and ocean. Most of the sea ice exiting the Arctic Ocean does so through Fram Strait, which is why long-term measurements of ice thickness at the end of the Transpolar Drift provide insight into the integrated signals of thermodynamic and dynamic influences along the pathways of Arctic sea ice. We present an updated summer (July- August) time series of extensive ice thickness surveys carried out at the end of the Transpolar Drift between 2001 and 2020. Overall, we see a more than 20 % thinning of modal ice thickness since 2001. A comparison of this time series with first preliminary results from the international Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) shows that the modal summer thickness of the MOSAiC floe and its wider vicinity are consistent with measurements from previous years at the end of the Transpolar Drift. By combining this unique time series with the Lagrangian sea ice tracking tool, ICETrack, and a simple thermodynamic sea ice growth model, we link the observed interannual ice thickness variability north of Fram Strait to increased drift speeds along the Transpolar Drift and the consequential variations in sea ice age. We also show that the increased increased influence of upward-directed ocean heat flux in the eastern marginal ice zones, termed Atlantification, is not only responsible for sea ice thinning in and around the Laptev Sea but also that the induced thickness anomalies persist beyond the Russian shelves and are potentially still measurable at the end of the Transpolar Drift after more than a year. With a tendency towards an even faster Transpolar Drift, winter sea ice growth will have less time to compensate for the impact processes, such as Atlantification, have on sea ice thickness in the eastern marginal ice zone, which will increasingly be felt in other parts of the sea-ice-covered Arctic.