Seeing in the dark: evolution of supraglacial lakes on the Greenland and Antarctic ice sheets during polar night

黑暗中的视觉：极夜期间格陵兰岛和南极冰原上冰上湖泊的演化

• 批准号: 2902592
• 金额: --
• 依托单位: Lancaster University
• 依托单位国家: 英国
• 项目类别: Studentship
• 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=studentship-2902592
• 关键词: Seeing; dark; evolution; supraglacial; lakes

The Greenland and Antarctic Ice Sheets are responsible for about a third of global sea level rise as a result of increased melting and changes to ice flow. Supraglacial lakes (SGLs) are becoming more abundant as a result of increased melting, and can act to speed up ice flow when they drain (Leeson et al., 2015). SGLs may be a potential feedback in the ice sheet system, since faster ice flow leads to thinning, which leads to more melting and SGL formation. There are tens of thousands of SGLs on Greenland alone, and so understanding their evolution is important, especially with respect to their drainage behavior. Until recently it was thought that SGL drainage occurs only during the summer months, however we now have compelling evidence for a small number of winter time drainage events (Benedeck et al., 2021). Winter lake drainage is likely to have a larger impact on ice flow than summer lake drainage because it is more slippery under the ice in winter. SGLs are typically studied at scale using optical satellite imagery (e.g. Corr et al., 2021), however optical satellites are unable to image the ice sheet surface in winter due to the darkness of the polar night. Recent advances in machine learning and data science however mean that it is now possible to 'see in the dark' and map supraglacial lakes during winter using Synthetic Aperture Radar (SAR) data. This PhD will exploit these advances to perform the first wide scale inventory of supraglacial lakes on Greenland and Antarctica during winter, and will use this inventory to understand the scale of wintertime lake drainage and examine its impact on ice flow.

由于融化和冰流变化的变化，格陵兰和南极冰盖造成了全球海平面上升的大约三分之一。由于熔化的增加，冰川上湖（SGL）变得越来越丰富，并且在耗尽冰流时可以加快冰流的速度（Leeson等，2015）。 SGLS可能是冰盖系统中的潜在反馈，因为更快的冰流会导致变薄，从而导致更多的熔化和SGL形成。仅格陵兰岛上就有成千上万的SGL，因此了解它们的进化很重要，尤其是在其排水行为方面。直到最近，人们认为SGL排水仅在夏季发生，但是我们现在有令人信服的证据证明少数冬季排水事件（Benedeck等，2021）。冬季湖水排水对冰流的影响可能比夏季湖水的排水更大，因为冬季在冰下面更滑。通常使用光学卫星图像（例如Corr等，2021）对SGL进行大规模研究，但是由于极性之夜的黑暗，光学卫星无法在冬季对冰盖表面进行成像。然而，机器学习和数据科学的最新进展意味着，现在可以使用合成孔径雷达（SAR）数据在冬季“在黑暗中看到”并在冬季地图上映射上湖上的湖泊。该博士将利用这些进步，在冬季在格陵兰岛和南极洲的第一个大规模扫盲湖泊进行大规模清单，并将利用此库存来了解冬季湖水排水的规模并检查其对冰流的影响。