不能排除当今南极接地线的稳定性——第2部分:阿蒙森海冰川在当前气候条件下以百年为时间尺度开始不可逆转的退缩

IF 4.4 2区 地球科学 Q1 GEOGRAPHY, PHYSICAL Cryosphere Pub Date : 2023-09-07 DOI:10.5194/tc-17-3761-2023
R. Reese, J. Garbe, Emily A. Hill, Benoît Urruty, K. Naughten, O. Gagliardini, G. Durand, F. Gillet-Chaulet, G. H. Gudmundsson, David Chandler, P. Langebroek, R. Winkelmann
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引用次数: 4

摘要

摘要对南极阿蒙森海堤海洋驱动的接地线退缩的观测提出了南极西部冰盖即将崩塌的问题。在这里,我们分析了在当今气候下南极接地线的坚定演变。为此,我们首先校准了一个亚大陆架熔体参数化,该参数化源于海洋箱模型,具有对海洋温度变化的观测和建模熔体敏感性,使其适用于当前的模拟和未来的海平面预测。使用新的校准,我们使用最先进的冰盖模型运行了1850年至2015年的一系列历史模拟,以创建当今可能的冰盖配置的模型实例。然后,我们将模拟扩展到另外10个 000年来研究它们在当今不断变化的气候强迫和水深测量下的进化。我们测试了在发生大规模撤退的情况下接地线运动的可逆性。在阿蒙森海堤,我们发现所有参数组合的斯维茨冰川都不可逆转地退缩,而一些可接受的参数组合的松岛冰川则不可逆转地退缩。重要的是,在我们的模拟中,阿蒙森海堤区的不可逆转的坍塌最早发生在300年至500年之间,而且还不是不可避免的——正如我们的配套论文(第1部分,Hill等人,2023)所示。换句话说,该地区还没有倾斜。在假设当前气候不变的情况下,崩溃在千禧一代的时间尺度上演变,最大速度为0.9 毫米 −1海平面等效冰体积损失。到2300年对海平面的贡献仅限于8 cm,最大速率为0.4 毫米 −1海平面等效冰体积损失。此外,当允许冰架再生到目前的几何形状时,我们发现大规模的接地线退缩到Filchner–Ronne冰架上游的海洋盆地和Siple海岸西部是可逆的。在当今气候下的所有配置中,其他接地线仍接近其当前位置。
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The stability of present-day Antarctic grounding lines – Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded
Abstract. Observations of ocean-driven grounding-line retreat in the Amundsen Sea Embayment in Antarctica raise the question of an imminent collapse of the West Antarctic Ice Sheet. Here we analyse the committed evolution of Antarctic grounding lines under the present-day climate. To this aim, we first calibrate a sub-shelf melt parameterization, which is derived from an ocean box model, with observed and modelled melt sensitivities to ocean temperature changes, making it suitable for present-day simulations and future sea level projections. Using the new calibration, we run an ensemble of historical simulations from 1850 to 2015 with a state-of-the-art ice sheet model to create model instances of possible present-day ice sheet configurations. Then, we extend the simulations for another 10 000 years to investigate their evolution under constant present-day climate forcing and bathymetry. We test for reversibility of grounding-line movement in the case that large-scale retreat occurs. In the Amundsen Sea Embayment we find irreversible retreat of the Thwaites Glacier for all our parameter combinations and irreversible retreat of the Pine Island Glacier for some admissible parameter combinations. Importantly, an irreversible collapse in the Amundsen Sea Embayment sector is initiated at the earliest between 300 and 500 years in our simulations and is not inevitable yet – as also shown in our companion paper (Part 1, Hill et al., 2023). In other words, the region has not tipped yet. With the assumption of constant present-day climate, the collapse evolves on millennial timescales, with a maximum rate of 0.9 mm a−1 sea-level-equivalent ice volume loss. The contribution to sea level by 2300 is limited to 8 cm with a maximum rate of 0.4 mm a−1 sea-level-equivalent ice volume loss. Furthermore, when allowing ice shelves to regrow to their present geometry, we find that large-scale grounding-line retreat into marine basins upstream of the Filchner–Ronne Ice Shelf and the western Siple Coast is reversible. Other grounding lines remain close to their current positions in all configurations under present-day climate.
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来源期刊
Cryosphere
Cryosphere GEOGRAPHY, PHYSICAL-GEOSCIENCES, MULTIDISCIPLINARY
CiteScore
8.70
自引率
17.30%
发文量
240
审稿时长
4-8 weeks
期刊介绍: The Cryosphere (TC) is a not-for-profit international scientific journal dedicated to the publication and discussion of research articles, short communications, and review papers on all aspects of frozen water and ground on Earth and on other planetary bodies. The main subject areas are the following: ice sheets and glaciers; planetary ice bodies; permafrost and seasonally frozen ground; seasonal snow cover; sea ice; river and lake ice; remote sensing, numerical modelling, in situ and laboratory studies of the above and including studies of the interaction of the cryosphere with the rest of the climate system.
期刊最新文献
Greenland and Canadian Arctic ice temperature profiles database The stability of present-day Antarctic grounding lines – Part 2: Onset of irreversible retreat of Amundsen Sea glaciers under current climate on centennial timescales cannot be excluded The stability of present-day Antarctic grounding lines – Part 1: No indication of marine ice sheet instability in the current geometry Phase-field models of floe fracture in sea ice Relevance of warm air intrusions for Arctic satellite sea ice concentration time series
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