Present day Jakobshavn Isbræ (West Greenland) close to the Holocene minimum extent
Present day Jakobshavn Isbræ (West Greenland) close to the Holocene minimum extent
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现在的雅各布港伊斯布雷（西格陵兰）接近全新世最小范围
DOI：
10.1016/j.quascirev.2020.106492
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发表时间：
2020
影响因子：
4
通讯作者：
K. Nisancioglu
中科院分区：
文献类型：
--
作者：
Karita Kajanto;H. Seroussi;Basile de Fleurian;K. Nisancioglu
海洋终止冰川在千年时间尺度上随着海洋和大气条件的变化而演变。然而，海洋和大气驱动因素的相对作用仍然不确定。在比现在更温暖的全新世气候条件下，海洋终止冰川的演变可以为了解冰流随气候演变的动态提供重要的见解。Jakobshavn Isbræ从末次冰期最大值到8.2 ka BP的全新世早期演化受到该地区地貌研究的约束。然而，冰川的全新世最小范围是未知的。本文采用高分辨率区域冰盖模型研究了Jakobshavn Isbræ从全新世中期到小冰期的退缩和前进过程。Jakobshavn Isbræ的这个模型准确地追踪了陆地冰缘，并与海洋接地线演变的现有估计相一致。我们发现，在6-5 ka BP，陆地冰缘和接地线的全新世最小范围与冰川的现今范围接近。我们还发现，冰川目前正接近一个临界点，超过这个临界点后，要想继续前进，就需要经历比小冰期更漫长、更显著的降温。我们评估了海洋强迫在解释Jakobshavn全新世演化中的重要性，并发现全新世中期峡湾内的冷却对冰川前进至关重要。这一发现强调了海洋强迫在试图理解海洋终止冰川千年尺度演变中的作用。
Marine terminating glaciers evolve on millenial timescales in response to changes in oceanic and atmospheric conditions. However, the relative role of oceanic and atmospheric drivers remains uncertain. The evolution of marine terminating glaciers under the warmer than present Holocene Climate Optimum climate can give important insights into the dynamics of ice streams as the climate evolves. The early Holocene evolution of Jakobshavn Isbræ, from the Last Glacial Maximum extent up to 8.2 ka BP is well constrained by geomorphological studies in the area. However, the Holocene minimum extent of the glacier is unknown. Here, we use a high-resolution regional ice sheet model to study the retreat and readvance of Jakobshavn Isbræ from the Mid-Holocene to the Little Ice Age. This model of Jakobshavn Isbræ accurately tracks the terrestrial ice margin and agrees with available estimates of marine grounding line evolution. We find that the Holocene minimum extent of both the terrestrial ice margin and the grounding line, reached at 6–5 ka BP, is close to the present day extent of the glacier. We also find that the glacier is currently located close to a tipping point, from beyond which readvance would require a longer and more significant cooling than the Little Ice Age. We assess the importance of the ocean forcing in explaining the Holocene evolution of Jakobshavn, and find that cooling within the fjord during the Mid-Holocene is critical for the glacier to readvance. This finding emphasizes the role of ocean forcing when trying to understand the millenial scale evolution of marine terminating glaciers.
影响因子：
18.3
作者：
S. Jamieson;A. Vieli;S. Livingstone;C. Ó. Cofaigh;C. Stokes;C. Hillenbrand;J. Dowdeswell
通讯作者：
S. Jamieson;A. Vieli;S. Livingstone;C. Ó. Cofaigh;C. Stokes;C. Hillenbrand;J. Dowdeswell
影响因子：
5.2
作者：
Gudmundsson, G. H.;Krug, J.;Gagliardini, O.
通讯作者：
Gagliardini, O.
影响因子：
18.3
作者：
Khazendar, Ala;Fenty, Ian G.;Willis, Josh
通讯作者：
Willis, Josh