East Antarctic Ice Sheet sensitivity under vulnerable conditions studied by combination of focused geophysical techniques

通过结合聚焦地球物理技术研究脆弱条件下东南部冰盖的敏感性

• 批准号: 522416134
• 负责人: Professor Dr. Karsten Gohl
• 金额: --
• 依托单位: Sektion Geophysik
• 依托单位国家: 德国
• 项目类别: Infrastructure Priority Programmes
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/522416134?language=en
• 关键词: East; Antarctic; Ice; Sheet; sensitivity

The long-standing paradigm that the East Antarctic Ice Sheet (EAIS) remains relatively stable, while only the marine-based West Antarctic Ice Sheet is vulnerable to the currently progressing climate change, has been challenged. The East Antarctic Ice Sheet around Denman Glacier in the Davis Sea sector of the southern Indian Ocean has recently been identified as potentially vulnerable to incursions of warm deep water. This is highly relevant for future climate and sea-level projections, because the potential ice mass loss of the Denman Glacier and connecting ice masses in its catchment hinterland would contribute to a sea-level rise of up to 1.5 to 2 m. Records of its behavior during past warm periods will provide constraints on this vulnerability. One of the basic data knowledge required for an assessment of past EAIS behavior is a mapping and analysis of the glacial-marine sediments on the continental shelf and rise as they represent archives of past ice sheet dynamics. Comprehensive shallow sub-surface hydroacoustic and high-resolution seismic to deep-basin seismic surveys on the continental shelf offshore Denman and neighboring outlet glaciers, to be acquired during RV Polarstern expedition PS141 in early 2024, will provide the key data of this project. The reconstructed seismic stratigraphy, linked to ocean drilling sites for chronostratigraphic control, will contain pattern of glacially transported sediments from erosion to deposition and, thus, enable a quantification of periods of major ice sheet advances and retreats. The combination of the different seismic recording setups will allow to image glacial structures at different depth at optimal resolution. In addition, the basement structures imaged by deep-basin seismics reveal tectonic lineaments and faults as well as former ice sheet grounding pinning points indicating possible extents of rift basins acting later as pathways for ice streams. The main work will be carried out by two PhD students, one at Kiel University and the other one at AWI, who will work very close together as the different hydroacoustic and seismic data sets complement each other. The reconstruction of glacial dynamics, in particular in past warm times, e.g. the Oligocene, Mid-Miocene, Pliocene warm periods as well as the last interglacials and retreat from the Last Glacial Maximum, will be used to feed the parameterization of paleo-ice sheet modelling simulations. The goal is to reveal the vulnerability of the East Antarctic Ice Sheet in warm periods in comparison to observations and models for the West Antarctic Ice Sheet. The results of this project will help lift the projections of the future behaviour of the East Antarctic Ice Sheet to a new level.

东南极冰盖（EAIS）的长期范式仍然相对稳定，而只有海洋的西部南极冰盖容易受到当前进展的气候变化的影响。印度洋南部戴维斯海域的丹曼冰川周围的东南极冰盖最近被确定为可能容易入侵温暖的深水。这与未来的气候和海平面预测非常相关，因为丹曼冰川的潜在冰质量损失以及在其流域腹地中连接冰块将导致海平面上升到1.5至2 m。在过去的温暖时期，其行为的记录将对这种脆弱性提供限制。评估过去EAIS行为所需的基本数据知识之一是对大陆架上的冰川海底沉积物进行映射和分析，并在代表过去的冰盖动力学的档案时上升。在2024年初的RV Polarstern Expedition PS141期间，将在RV Polarstern Expedition PS141上获得综合的浅层氢声和高分辨率地震调查，以对大陆货架岛岛离岸丹曼和邻近的出口冰川进行。重建的地震地层图与海洋钻井位点有关，用于年度地层控制，将包含冰川运输的沉积物的模式，从侵蚀到沉积，因此可以量化主要的冰盖前进和撤退的时期。不同的地震记录设置的组合将允许在最佳分辨率下以不同深度的冰川结构进行成像。此外，由深层地震学成像的基底结构揭示了构造谱系和断层以及以前的冰盖接地钉点，表明裂谷盆地可能后来用作冰流的途径。主要工作将由两名博士学位学生进行，其中一名在基尔大学（Kiel University），另一项是AWI，他们将随着不同的水声和地震数据集相互补充，他们将非常亲密。冰川动力学的重建，特别是在过去的温暖时期，例如渐新世，中新世，上新世暖时期以及最后一次冰川间的冰期最大冰期最大的撤退，将用于喂养古冰板建模模拟的参数化。与南极冰盖的观察和模型相比，与观测和模型相比，在温暖时期内揭示了东南极冰盖的脆弱性。该项目的结果将有助于将东南极冰盖未来行为的预测提升到一个新的水平。