Measuring Antarctic uplift due to ice loss, from space

从太空测量由于冰损失导致的南极隆起

• 批准号: 2603896
• 金额: --
• 依托单位: University of Leeds
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2021
• 资助国家: 英国
• 起止时间: 2021 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2603896
• 关键词: Measuring; Antarctic; uplift; due; ice

This exciting project will use measurements of ground movement made from space, to constrain the response of the ground to current, and past, ice mass change in the Antarctic. This in turn will improve estimates of ongoing ice loss. The student will be based in Leeds and optional fieldwork in the Antarctic will be involved.Ice loss from the West Antarctic Ice Sheet already accounts for around 10% of present-day global sea-level rise and is accelerating. As the mass of the ice changes, the ground beneath responds to the change in surface loading both immediately, and with a delayed response lasting up to thousands of years, an effect known as glacial isostatic adjustment (GIA). Understanding the GIA response is key to constraining ongoing ice loss, as it also affects the main measurement methods used to constrain ongoing ice loss: satellite gravimetry and altimetry.The GIA response depends on the flow characteristics (rheology) of the mantle, which are vertically and laterally variable, and poorly known. Those constraints we do have come from seismic studies and also from viscoelastic modelling of ground motion measurements made by GNSS (e.g. Nield et al, 2014; Samrat et al, 2020). However, the logistical challenge of running GNSS instruments in such a hostile and remote location means that the measurements are spatially sparse, and are not able to capture the full variability of ground displacements, as individual glaciers respond differently to changing conditions.Radar Interferometry (InSAR), on the other hand, is a technique that can provide spatially dense measurements of surface displacement from space (Hooper et al, 2012). Making these measurements in the Antarctic is challenging, due to snow coverage in winter and with large regions covered by ice, but our preliminary efforts have shown it to be possible.InSAR is commonly used in the natural hazards community for earthquake analysis and monitoring of volcanoes, and at the University of Leeds we have developed algorithms for mass processing of data, and the reduction of measurement errors introduced by variable atmospheric conditions. InSAR is also used for commercial applications, such as monitoring of infrastructure, and SatSense Ltd have developed their own state-of-the-art approach to InSAR processing and interpretation.The aim of this project is to use the combined expertise from Leeds and SatSense to make InSAR measurements over the whole Antarctic Peninsula and, working with experts in BAS and Durham, to use these data to better constrain the rheological properties of the region through modelling. The project will also involve fieldwork to install radar reflectors at key locations on the Antarctic Peninsula, subject to a successful application for support from BAS. This will enable the InSAR results, which are relative measurements, to be tied to a global reference frame.Specific objectives are:Process InSAR data for the whole Antarctic Peninsula and extract time series for individual rocky outcrops;Apply the latest atmospheric correction techniques to the InSAR data;Install radar reflectors on the peninsula to provide absolute constraints on velocity;Use the InSAR measurements combined with GNSS data to constrain viscoelastic models.ReferencesHooper, A., Bekaert, D., Spaans, K. and Arikan, M., 2012. Recent advances in SAR interferometry time series analysis for measuring crustal deformation. Tectonophysics, 514, pp.1-13.Nield, G. A., et al. 2014. Rapid bedrock uplift in the Antarctic Peninsula explained by viscoelastic response to recent ice unloading. Earth and Planetary Science Letters, 397, 32-41.Samrat, Nahidul Hoque, et al. "Reduced ice mass loss and three-dimensional viscoelastic deformation in northern Antarctic Peninsula inferred from GPS

这个令人兴奋的项目将使用从太空测量的地面运动，以限制地面对南极当前和过去冰量变化的反应。这反过来将改善对持续冰损失的估计。该学生将在利兹和可选的实地考察将涉及。冰从南极洲西部冰盖的损失已经占约10%，目前全球海平面上升，并正在加速。随着冰的质量发生变化，下面的地面对表面负荷的变化做出反应，这种反应可以立即进行，也可以延迟数千年，这种效应被称为冰川均衡调整（GIA）。了解GIA响应是限制持续冰损失的关键，因为它也影响用于限制持续冰损失的主要测量方法：卫星重力测量和测高。GIA响应取决于地幔的流动特性（流变学），这些特性在垂直和横向上是可变的，并且知之甚少。我们所做的这些限制来自地震研究，也来自GNSS对地面运动测量的粘弹性建模（例如Nield等人，2014; Samrat等人，2020）。然而，在如此恶劣和偏远的地点运行全球导航卫星系统仪器的后勤挑战意味着测量在空间上是稀疏的，并且不能够捕获地面位移的全部可变性，因为各个冰川对变化的条件的反应不同。另一方面，雷达干涉测量（干涉合成孔径雷达）是一种能够从空间提供表面位移空间密集测量的技术（Hooper等人，2012）。在南极进行这些测量具有挑战性，因为冬季积雪覆盖，大面积区域被冰覆盖，但我们的初步努力表明这是可能的。干涉合成孔径雷达通常用于自然灾害社区的地震分析和火山监测，在利兹大学，我们已经开发了大量数据处理算法，以及减少由变化的大气条件引入的测量误差。干涉合成孔径雷达也用于商业应用，如基础设施的监测，SatSense有限公司已经开发了自己的最先进的干涉合成孔径雷达处理和解释方法。该项目的目的是利用利兹和SatSense的综合专业知识对整个南极半岛进行干涉合成孔径雷达测量，并与BAS和达勒姆的专家合作，利用这些数据，通过建模更好地约束该地区的流变特性。该项目还将包括在南极半岛的关键地点安装雷达反射器的实地工作，前提是成功申请BAS的支持。具体目标是：处理整个南极半岛的干涉合成孔径雷达数据并提取单个岩石露头的时间序列;对干涉合成孔径雷达数据应用最新的大气校正技术;在半岛上安装雷达反射器以提供对速度的绝对约束;将干涉合成孔径雷达测量结果与GNSS数据结合使用以约束粘弹性模型。Bekaert，D.，Spaans，K.和Arikan，M.，2012.用于测量地壳形变的合成孔径雷达干涉测量时间序列分析的最新进展。《构造物理学》，514，第1 - 13页.一、等，2014年。南极半岛快速基岩隆起对最近冰卸载的粘弹性反应的解释。地球和行星科学快报，397，32- 41. Samrat，Nahidul Hoque等.“从GPS推断的南极半岛北方减少的冰质量损失和三维粘弹性变形