Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska
Degradation and stabilization of ice wedges: Implications for assessing risk of thermokarst in northern Alaska
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冰楔的退化和稳定：对评估阿拉斯加北部热喀斯特风险的影响
DOI：
10.1016/j.geomorph.2017.09.001
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发表时间：
2017
期刊：
影响因子：
3.9
通讯作者：
Buchhorn, Marcel
中科院分区：
文献类型：
--
作者：
Kanevskiy, Mikhail;Shur, Yuri;Jorgenson, Torre;Brown, Dana R.N.;Moskalenko, Nataliya;Brown, Jerry;Walker, Donald A.;Raynolds, Martha K.;Buchhorn, Marcel
在过去几十年中，在欧亚大陆和北美连续多年冻土带内的许多地区观察到了广泛的冰楔退化。为了研究冰楔的退化，我们于2011-2016年间在阿拉斯加北部的普拉德霍湾和巴罗进行了实地调查。在每个研究区域，建立了一个250米的样带，用地块表示冰楔退化/稳定的不同阶段。实地工作包括测量地面和水面高度、融化深度测量、永久冻土取心、植被采样和地面激光雷达扫描。我们描述了冻土的低温地层学和稳定同位素组成，分析了与冰楔退化和稳定有关的环境特征，评估了冰楔对气候变化和扰动的脆弱性和恢复力，并建立了新的冰楔动力学概念模型，确定了影响冰楔退化和稳定的主要因素和这一准循环过程的主要阶段。我们发现这两个地区的冰楔退化和稳定的模式存在显著差异，而且由于地形变化、水再分配和植被/土壤反应的相互作用，冰楔退化和稳定的模式比之前描述的更加复杂，这些相互作用可以中断或加强退化。冰楔的退化通常是由异常温暖潮湿的夏季活动层厚度增加或洪水或干扰引起的。冰楔对热岩溶的脆弱性由上层永久冻土的中间层厚度控制，该中间层覆盖在冰楔上，保护它们不会融化。在连续的永久冻土区，冰楔的退化很少导致其完全融化；在大多数情况下，冰楔最终稳定下来，然后可以恢复生长，这表明这是一个有点循环和可逆的过程。冰楔部分退化后的稳定使其得到比退化前更好的保护，因为在未受干扰的情况下，稳定的冰楔顶部的中间层通常是初始冰楔顶部的2-3倍厚。因此，仅由冰楔退化引发的连续多年冻土区形成大型融化湖泊的可能性非常低。
Widespread degradation of ice wedges has been observed during the last decades in numerous areas within the continuous permafrost zone of Eurasia and North America. To study ice-wedge degradation, we performed field investigations at Prudhoe Bay and Barrow in northern Alaska during 2011–2016. In each study area, a 250-m transect was established with plots representing different stages of ice-wedge degradation/stabilization. Field work included surveying ground- and water-surface elevations, thaw-depth measurements, permafrost coring, vegetation sampling, and ground-based LiDAR scanning. We described cryostratigraphy of frozen soils and stable isotope composition, analyzed environmental characteristics associated with ice-wedge degradation and stabilization, evaluated the vulnerability and resilience of ice wedges to climate change and disturbances, and developed new conceptual models of ice-wedge dynamics that identify the main factors affecting ice-wedge degradation and stabilization and the main stages of this quasi-cyclic process. We found significant differences in the patterns of ice-wedge degradation and stabilization between the two areas, and the patterns were more complex than those previously described because of the interactions of changing topography, water redistribution, and vegetation/soil responses that can interrupt or reinforce degradation. Degradation of ice wedges is usually triggered by an increase in the active-layer thickness during exceptionally warm and wet summers or as a result of flooding or disturbance. Vulnerability of ice wedges to thermokarst is controlled by the thickness of the intermediate layer of the upper permafrost, which overlies ice wedges and protects them from thawing. In the continuous permafrost zone, degradation of ice wedges rarely leads to their complete melting; and in most cases wedges eventually stabilize and can then resume growing, indicating a somewhat cyclic and reversible process. Stabilization of ice wedges after their partial degradation makes them better protected than before degradation because the intermediate layer is usually 2 to 3 times thicker on top of stabilized ice wedges than on top of initial ice wedges in undisturbed conditions. As a result, the likelihood of formation of large thaw lakes in the continuous permafrost zone triggered by ice-wedge degradation alone is very low.
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DOI：
10.1002/2014jf003085
发表时间：
2014-09
期刊：
Journal of Geophysical Research: Earth Surface
影响因子：
--
作者：
S. Kokelj;T. Lantz;S. A. Wolfe;J. Kanigan;P. Morse;R. Coutts;N. Molina-Giraldo;C. Burn
通讯作者：
S. Kokelj;T. Lantz;S. A. Wolfe;J. Kanigan;P. Morse;R. Coutts;N. Molina-Giraldo;C. Burn
影响因子：
5
作者：
Fortier, Daniel;Allard, Michel;Shur, Yuri
通讯作者：
Shur, Yuri
阿拉斯加北部冰楔上形成的苔原土壤1
DOI：
--
发表时间：
1967
期刊：
影响因子：
--
作者：
Jerry Brown
通讯作者：
Jerry Brown
对历史航空照片和最新卫星图像的多时相图像分析揭示了阿拉斯加科伯克谷国家公园水体表面积和多边形地形形态的演变
DOI：
--
发表时间：
2013
期刊：
影响因子：
--
作者：
M. Necsoiu;C. Dinwiddie;G. R. Walter;A. Larsen;S. Stothoff
通讯作者：
S. Stothoff
影响因子：
3.9
作者：
Jorgenson, M. Torre;Shur, Yuri
通讯作者：
Shur, Yuri