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遥远和难以到达的极地地区的认识。如果没有这一关键资源，我们对哪些地区正在发生变化、事件发生的时间和速度以及驱动变化的物理机制的了解将远远不够全面。在南极洲，卫星数据对于揭示整个大陆冰流的空间格局至关重要；揭示了南极西部海基冰盖的动力不平衡及其对海平面的巨大贡献；绘制海冰面积的季节性增长和衰减图；以及测量臭氧空洞的大小和恢复。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，尽管在许多地区冰速度有明显的长期增加趋势，但观测到的冰速度加快并非随时间而恒定不变，也观测到多年无显著变化。目前有必要对冰速进行测量，以提供一种独立的方法来测量这个巨大冰盖上变化最迅速地区的冰质量损失。这个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影响的国际努力作出重要贡献。该博士生将详细了解如何处理来自ERS-1/2、TerraSAR-X、Sentinel-1等大量地球观测卫星的合成孔径雷达（SAR）数据，使用干涉测量（InSAR）和特征跟踪等多种处理技术进行冰速测量。冰速测量将与床和冰表面地形结合使用，以计算南极冰盖上单个冰川的冰通量，然后计算其质量平衡。将对冰速测量结果进行分析，以检测速度随时间的变化，并将其与诸如产犊前沿位置和冰变薄等补充观测相结合，以推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展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。在攻读博士学位期间，学生将在这些重要的科学课题上至少发表三篇期刊论文，并有可能进行极地考察活动。该博士生将在利兹大学的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（ESA）合作和参加会议，并与广泛的国际科学合作者接触。在CPOM的学生提供了一个极好的机会，与英国各地大学的陆地和海冰观测和建模专家组成的大型团队积极合作。该项目提供以下方面的高水平培训：(i)卫星遥感；极地实地考察；(3)冰川学;（iii）数据分析和可视化；（iv）校正和验证卫星系统；（五）科学写作。成功的申请者将有机会在地球观测和冰川学方面进行广泛的专业培训，此外还有广泛的利兹大学关于一系列主题的研讨会，包括科学规划到管理你的学位。申请人须持有物理、数学、地球科学、气候科学、地球观测或相关学科的学士学位或硕士学位。在计算机编程方面的专业知识，虽然不是必需的，将是一个有价值的资产。

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.