Change in the ice speed and mass balance of the Antarctic Ice Sheet, from Earth Observation satellite data

卫星地球观测彻底改变了我们对偏远和难以到达的极地地区的理解。如果没有这一关键资源，我们将无法完全了解哪些区域正在发生变化，事件发生的时间和速度，以及哪些物理机制负责推动变化。在南极洲，卫星数据对于揭示整个大陆的冰流空间格局、揭示动态不平衡和海洋西南极冰盖对海平面的相关巨大贡献、绘制海冰范围的季节性增长和衰减图以及测量臭氧洞的大小和恢复情况至关重要。在过去的30年里，南极洲的个别冰流，如松岛冰川，自20世纪90年代初以来，速度增加了42%以上，现在已知是动态不平衡的。然而，尽管在许多地区有明显的冰速增加的长期趋势，但观测到的冰速增加并不是一个常数，而且还观察到多年来没有显著变化。有必要对冰的速度进行现代测量，以便提供一种独立的手段，测量这一巨大冰盖变化最迅速的区域的冰质量损失，该项目提供了一个令人兴奋的机会，可以在气候和空间科学的界面上工作，为研究气候变化的影响和作用的国际努力作出重要贡献。该博士生将获得如何处理合成孔径雷达（SAR）数据从大量的地球观测卫星，包括ERS-1/2，TerraSAR-X，哨兵-1，使用多种处理技术，如干涉测量（干涉合成孔径雷达）和功能跟踪的详细技术理解，使冰速度的测量。冰速的测量结果将与冰床和冰面地形结合使用，以计算南极冰盖上各个冰川的冰通量，然后计算质量平衡。冰速测量将被分析，以检测速度随时间的变化，这将与免费的观察相结合，如崩解锋的位置和冰变薄，以促进我们对驱动变化的物理机制的理解。这些结果将用于改善和扩大冰盖对当今海平面上升的贡献，这是一个具有广泛社会重要性的话题，并将使我们能够更好地预测冰盖未来将如何变化。学生将在博士期间领导至少三篇关于这些重要科学主题的期刊论文，并可能有可能进行极地运动。该博士生将在利兹大学极地观测和建模中心（CPOM）工作，因此将有宝贵的机会与欧洲航天局（欧空局）合作并参加会议，并与广泛的国际科学合作者合作。CPOM内的学生奖学金提供了一个绝佳的机会，可以与英国各地大学的大型陆地和海冰观测和建模专家团队积极合作。该项目提供以下方面的高级培训：㈠卫星遥感; ㈡极地实地考察; ㈢冰川学; ㈢数据分析和可视化; ㈣卫星系统的校准和验证; ㈤科学写作。成功的申请人将有机会获得广泛的地球观测和冰川学专业培训，除了广泛的利兹大学研讨会上的一系列主题，包括科学规划通过管理你的学位。申请人将持有良好的第一学位（第一或高2.1）或硕士学位，物理，数学，地球科学，气候科学，地球观测或相关学科。计算机编程方面的专业知识，虽然不是必需的，但将是一笔宝贵的财富。

Satellite Earth Observation has revolutionized our understanding of the remote and inaccessible Polar Regions. Without this critical resource we would have a far less complete understanding of which regions are changing, the timing and pace at which events occur, and what physical mechanisms are responsible for driving change. In Antarctica, satellite data has been vital for revealing the continent-wide spatial pattern of ice flow; for uncovering dynamic imbalance and the associated large sea level contribution of the marine-based West Antarctic Ice Sheet; for mapping the seasonal growth and decay of sea ice extent; and for measuring the size and recovery of the Ozone hole. During the last 30-years, individual ice streams in Antarctica such as Pine Island Glacier, have increased in speed by over 42% since the early 1990's, and are now known to be dynamically imbalanced. However, despite a clear long-term trend for increasing ice velocity in many regions, the observed speed up has not been constant through time, and multiple years with no significant change have also been observed. It is necessary to make present day measurements of ice velocity to provide an independent means of measuring ice mass loss from the most rapidly changing regions of this vast ice sheet.This project offers an exciting opportunity to work at the interface of climate and space science, making an important contribution to international efforts to study the effects and impact of climate change. This PhD student will gain a detailed technical understanding of how to process Synthetic Aperture Radar (SAR) data from a large number of Earth Observation satellites, including ERS-1/2, TerraSAR-X, Sentinel-1, using multiple processing techniques, such as interferometry (InSAR) & feature tracking, to make measurements of ice speed. The measurements of ice speed will be used in combination with bed and ice surface topography to compute the ice flux, and then mass balance, of individual glaciers on the Antarctic Ice Sheet. The ice speed measurements will be analysed to detect change in speed over time, and this will be combined with complimentary observations, such as the calving front location and ice thinning, to advance our understanding of the physical mechanisms driving change. These results will be used to improve and extend the ice sheet contribution to present-day sea-level rise, a topic of wide societal importance, and will enable us to better predict how the ice sheet will change in the future. The student will lead at least three journal papers on these important science topics during the course of their PhD, and may have the possibility of undertaking a Polar field campaign. The PhD student will be based within the Centre for Polar Observation and Modelling (CPOM) at the University of Leeds, and will therefore have valuable opportunities to work with and attend meetings at the European Space Agency (ESA), and to engage with a wide range of international scientific collaborators. A studentship within CPOM provides a fantastic opportunity to actively collaborate with a large team of land and sea ice observation and modelling experts at universities across the UK. The project provides a high level of training in: (i) satellite remote sensing; (ii) polar fieldwork; (iii) glaciology; (iii) data analysis and visualization; (iv) calibration and validation of satellite systems; and (v) scientific writing. The successful applicant will have access to a broad spectrum of specialist training in Earth Observation and glaciology, in addition to the extensive University of Leeds workshops on a range of topics, including scientific programming through to managing your degree. Applicants will hold good first degree (first or high 2.1) or Masters degree in physics, maths, Earth science, climate science, Earth observation or a related discipline. Expertise in computer programming, while not required, will be a valuable asset.