NSFGEO-NERC: Investigating the direct influence of meltwater on Antarctic Ice Sheet dynamics

NSFGEO-NERC：研究融水对南极冰盖动力学的直接影响

• 批准号: NE/Y006291/1
• 负责人: Andrew Sole
• 金额: $ 32.1万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FY006291%2F1
• 关键词: NSFGEO; NERC; Investigating; direct; influence

Surface melting is widespread around the periphery of Antarctica and predicted to increase significantly. This could impact sea-level rise by allowing surface-derived meltwater to reach the ice-sheet bed and modify glacier flow into the ocean. This mechanism has received little attention in Antarctica, partly because evidence for it happening today has only recently been published, by members of our team. This mechanism is likely to become increasingly important as Antarctica warms and we will take the first steps towards understanding and predicting these changes. We will test three hypotheses: (1) short-term changes in ice velocity indicated by satellite data result from surface meltwater reaching the bed of outlet glaciers in the Antarctic Peninsula, (2) this is widespread in Antarctica today, and (3) this results in a measurable increase in mean annual ice discharge.We propose a targeted field campaign supported by the British Antarctic Survey (BAS) on an Antarctic Peninsula outlet glacier, to test hypothesis 1 using a combination of well-established and more experimental techniques. BAS will support the fieldwork because of our field site's proximity to Rothera Research Station. Immediate outcomes will include a direct comparison of in situ melt rates (from energy-budget weather stations) and ice dynamic changes (from GPS and uncrewed aerial vehicles) and subglacial water flow (from passive seismometers and ice-penetrating radar). We will also conduct a continent-wide remote sensing survey, using synthetic aperture radar and multi-spectral imagery to comprehensively map meltwater on grounded ice (most similar efforts have focused on floating ice shelves) and short-term velocity variations. Comprehensive new datasets from the field and remote-sensing surveys will be used to test our three hypotheses.There is rapid growth in the glaciology community's interest in surface melting and hydrology on Antarctic ice shelves. This project will take the discipline in a new, but related direction and make important progress in understanding the different processes involved in the response of grounded ice to increasing melt rates. As one of the first projects to focus on this aspect of atmosphere/ice-dynamics coupling, we will produce early insights into both the drivers and implications of short-term changes in ice flow velocity caused by surface melting. For example, showing conclusively that meltwater directly impacts Antarctic ice dynamics would have significant implications for our understanding of the response of Antarctica to atmospheric warming, as it did in Greenland when the phenomenon was first detected there nearly 20 years ago. This work will also have implications for other fields, as surface-to-bed meltwater flow may have implications for ice rheology, subglacial hydrology, submarine melting and calving, ocean circulation, and ocean biogeochemistry.

地表熔化在南极外围周围广泛，预计会显着增加。这可能会通过允许表面衍生的融水到达冰层并修改冰川流入海洋的情况来影响海平面的上升。这种机制在南极洲很少关注，部分原因是我们团队成员最近才发布了今天发生的证据。随着南极的温暖，这种机制可能变得越来越重要，我们将迈出第一步，以理解和预测这些变化。我们将检验三个假设：（1）卫星数据所指示的冰速度的短期变化是由于地表融化到达南极半岛出口冰川床而导致的，（2）这在今天的南极洲很广泛，（3）（3）在平均冰出earting犬中，在平均冰上竞选活动中，这是一项可衡量的结果。半岛出口冰川，使用建立良好和更多实验技术的组合来检验假设1。由于我们的现场站点靠近罗瑟拉研究站，BAS将支持现场工作。直接的结果将包括对原位熔体速率（来自能量预算的气象站）和冰动态变化（从GPS和未被拖放的空中车辆）和冰川下水流（来自被动地震仪和冰渗透雷达）的直接比较。我们还将使用合成的光圈雷达和多光谱图像进行整体绘制冰上的融化冰层（大多数类似的努力都集中在浮冰架上）和短期速度变化。该领域的全面新数据集和遥感调查将用于检验我们的三个假设。冰川学界对南极冰架上表面融化和水文学的兴趣迅速增长。该项目将使该学科朝着一个新的但相关的方向发展，并在理解接地冰对提高熔体速率的响应中所涉及的不同过程中取得了重要进展。作为首批专注于大气/冰动力耦合这一方面的项目之一，我们将对驱动因素的驱动因素和造成冰流速度的短期变化的影响以及由表面融化引起的含义产生早期见解。例如，最终证明融化直接影响南极冰动力学对我们对南极对大气变暖的反应的理解具有重要意义，就像在格陵兰岛在大约20年前首次在那里发现了这一现象时所做的那样。这项工作也将对其他领域产生影响，因为地表到床的融化流量可能对冰流变，冰川下水文学，海底熔化和产犊，海洋循环和海洋生物地球化学有影响。