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.

由于融化加剧和冰流变化，格陵兰岛和南极冰盖造成了全球海平面上升的约三分之一。由于融化速度加快，冰上湖泊（SGL）变得更加丰富，并且在排水时可以加速冰流（Leeson 等，2015）。 SGL 可能是冰盖系统中的潜在反馈，因为更快的冰流会导致冰层变薄，从而导致更多的融化和 SGL 的形成。仅格陵兰岛就有数以万计的 SGL，因此了解它们的演变非常重要，特别是在它们的排水行为方面。直到最近，人们还认为 SGL 排水仅发生在夏季，但我们现在有令人信服的证据表明存在少量冬季排水事件（Benedeck 等人，2021 年）。冬季湖泊排水可能比夏季湖泊排水对冰流产生更大的影响，因为冬季冰下更滑。 SGL 通常使用光学卫星图像进行大规模研究（例如 Corr 等人，2021），但是由于极夜的黑暗，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“在黑暗中观察”并绘制冬季冰上湖泊的地图。该博士将利用这些进展对格陵兰岛和南极洲冬季的冰上湖泊进行首次大规模清查，并将利用该清查来了解冬季湖泊排水的规模并研究其对冰流的影响。