Reconstructing millennial-scale ice sheet change in the western Amundsen Sea Embayment, Antarctica, using high-precision exposure dating.

利用高精度曝光测年重建南极洲阿蒙森海湾西部千年规模的冰盖变化。

• 批准号: NE/K012088/1
• 负责人: Joanne Johnson
• 金额: $ 43.64万
• 依托单位: British Antarctic Survey
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FK012088%2F1
• 关键词: Reconstructing; millennial; scale; ice; sheet

Accurate prediction of when and how much sea level rise is likely to take place in the future is of great societal and economic importance if governments are to successfully plan for the future in a warming world. The West Antarctic Ice Sheet (WAIS), and particularly its Amundsen Sea sector, is key to such predictions because it has the potential to retreat very rapidly, perhaps over just a few centuries. We urgently need improvements to models that predict its future stability because the water locked inside it has the potential to make a major contribution (up to 1.2 metres) to global sea level rise. This would result in widespread damage to low-lying cities around the world, including major coastal and economic hubs in Europe, such as London. Information about the past size and shape of ice sheets is essential for testing and refining predictive models. However, despite its importance for understanding future sea level rise, modelling efforts in the Amundsen Sea Embayment (ASE) of Antarctica are currently hindered by a lack of data on the history of the WAIS, particularly in the western ASE (we know the general pattern of retreat and thinning in the eastern ASE, although some of the details are not yet clear). The proposed project will produce a unique high-resolution record of ice sheet thinning over the past 20,000 years from the poorly-known western ASE. We will use exciting innovations in the technique of surface exposure dating to determine small fluctuations in ice sheet thickness with greater precision than has previously been achieved in Antarctica. Information on the shape and size of the WAIS over the past 20,000 years is contained within rocks deposited on the surface of Antarctica as the ice sheet has retreated and thinned since that time. Surface exposure dating involves collecting such rocks and measuring the abundance of an isotope, 10Be, concentrated within their upper surfaces, which acts as a chemical signal for the length of time since the rock was last covered by ice. Because we plan to collect this information from a range of heights above today's ice surface in the western ASE, we will be able to tell how rapidly that part of WAIS has thinned, and when the thinning started and stopped. As well as establishing the history of this part of the WAIS, this approach will also give us insight into the significance of ice sheet changes recorded and widely publicised over the past decade. For example, are they simply the continuation of a long-term trend of thinning, or have they only started happening relatively recently and, if so, why? By comparing the retreat history of glaciers in the western and eastern parts of the ASE, we will also learn how different parts of the ASE are likely to respond to future environmental change.An important part of our proposal will be to further develop our existing collaborations with modellers who use geological data to test and tune their ice sheet models. Our data will permit significant improvements in these models, ultimately contributing to more accurate prediction of future global sea level rise.

如果政府要在温暖的世界中成功计划未来，那么对未来何时以及多少海平面上升的准确预测将具有极大的社会和经济重要性。南极冰盖（WAIS），尤其是其Amundsen Sea区，是此类预测的关键，因为它有可能很快撤退，也许只有几个世纪。我们迫切需要改进预测其未来稳定性的模型，因为锁定在其中的水有可能对全球海平面上升做出重大贡献（高达1.2米）。这将导致对世界各地低洼城市的广泛破坏，包括欧洲的主要沿海和经济枢纽，例如伦敦。有关冰盖过去大小和形状的信息对于测试和完善预测模型至关重要。然而，尽管它对于了解未来的海平面上升的重要性，但目前缺乏关于WAIS历史的数据，尤其是在西部的ASE（我们知道一般模式尽管尚不清楚一些细节，但在东部地区的撤退和稀疏。拟议的项目将在过去20，000年内从众所周知的西部ASE产生独特的冰盖稀疏记录。我们将在表面暴露日期的技术中使用令人兴奋的创新，以确定冰盖厚度的微小波动，其精度比南极洲先前更高。自那时以来，冰盖已经退缩和稀疏，有关过去20,000年中wais的形状和大小的信息包含在沉积在南极洲表面的岩石中。表面曝光日期涉及收集此类岩石并测量集中在其上表面内的同位素的丰度，这在其上表面上充当化学信号，因为岩石最后一次被冰覆盖以来。因为我们计划从西部西部的当今冰表面以上的一系列高度收集这些信息，所以我们将能够说出WAIS的那部分变化的速度以及稀疏开始和停止的何时。除了建立WAIS这部分的历史外，这种方法还将让我们深入了解过去十年记录并广泛宣传的冰盖变化的意义。例如，它们是否仅仅是延长长期趋势的延续，还是只是最近才开始发生相对发生的事情，如果是的话，为什么？通过比较ASE西部和东部冰川的静修历史，我们还将学习ASE的不同部分如何应对未来的环境变化。我们的建议的重要部分是进一步发展我们现有的合作与使用地质数据测试和调整其冰盖模型的建模者。我们的数据将允许这些模型的重大改进，最终有助于更准确地预测未来的全球海平面上升。

项目成果

Stability of the Antarctic Ice Sheet during the pre-industrial Holocene

• DOI: 10.1038/s43017-022-00309-5
• 发表时间: 2022-07
• 期刊: Nature Reviews Earth & Environment
• 影响因子: 42.1
• 作者: Richard S. Jones;Joanne S. Johnson;Yucheng Lin;A. Mackintosh;J. Sefton;James A. Smith;E. Thomas;P. Whitehouse

Deglaciation of Pope Glacier implies widespread early Holocene ice sheet thinning in the Amundsen Sea sector of Antarctica

• DOI: 10.1016/j.epsl.2020.116501
• 发表时间: 2020-10-15
• 期刊: EARTH AND PLANETARY SCIENCE LETTERS
• 影响因子: 5.3
• 作者: Johnson, Joanne S.;Roberts, Stephen J.;Smith, James A.
• 通讯作者: Smith, James A.

Comparing Glacial-Geological Evidence and Model Simulations of Ice Sheet Change since the Last Glacial Period in the Amundsen Sea Sector of Antarctica

• DOI: 10.1029/2020jf005827
• 发表时间: 2021-06-01
• 期刊: JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
• 影响因子: 3.9
• 作者: Johnson, Joanne S.;Pollard, David;Schaefer, Joerg M.
• 通讯作者: Schaefer, Joerg M.

The last glaciation of Bear Peninsula, central Amundsen Sea Embayment of Antarctica: Constraints on timing and duration revealed by in situ cosmogenic 14C and 10Be dating

• DOI: 10.1016/j.quascirev.2017.11.003
• 发表时间: 2017-12-15
• 期刊: QUATERNARY SCIENCE REVIEWS
• 影响因子: 4
• 作者: Johnson, Joanne S.;Smith, James A.;Gohl, Karsten
• 通讯作者: Gohl, Karsten

New 10 Be exposure ages improve Holocene ice sheet thinning history near the grounding line of Pope Glacier, Antarctica

新的 10 Be 暴露年龄改善了南极洲教皇冰川接地线附近的全新世冰盖变薄历史

• DOI: 10.5194/tc-2022-82
• 发表时间: 2022
• 作者: Adams J