The application of millimetre wave radar to the study of volcano-glacier interactions and ice-ocean interactions in conditions of reduced visibility.

这个博士学位的总体目标是开发毫米波雷达在地球科学中的应用，重点是火山冰川和冰海洋的相互作用。毫米波雷达与传统的光学勘测方法相比，具有一个关键的优势，即它能够在能见度降低的条件下以高分辨率绘制地形图。由Macfarlane和Robertson在圣安德鲁斯大学开发的AVTIS雷达用于火山成像[1]，已经证明了这种仪器通过完全遮蔽（例如火山灰，云）来绘制火山地形变化的潜力。除地形外，毫米波雷达还可以测量反射率和移动目标的速度，包括高时空分辨率的降雨量测绘。将开发和改进数字高程模型提取和根据反射率或标准化雷达截面区分地形类型的方法，以改进不同地形表面类型的分类。这些是研究火山-冰川相互作用和相关危害的核心，但人们对火山-冰川相互作用和相关危害的了解仍然很少（例如2010年埃亚菲亚德拉冰盖喷发），因为喷发期间的关键活动时期往往被掩盖。AVTIS雷达将阐明火山和冰川几何形状的变化，影响喷发时间、规模或融水引起的质量运动，例如火山泥流。因此，第一个案例研究将针对冰盖火山（如冰岛）。冰川和冰盖边缘的冰山崩解对于我们理解格陵兰冰盖在不久的将来对海平面上升的贡献至关重要。因此，在云层和降水量大的情况下，需要对地面冰缘进行连续监测，而在这种情况下，常规技术（激光雷达和延时摄影）已无用武之地。毫米波雷达在这些条件下生成数字高程模型的能力将是非常宝贵的。因此，该项目的第二阶段将是用AVTIS-2雷达进行冰川测绘，这在以前的文献中从未有过报道。该项目将大致遵循以下结构：-利用现有AVTIS数据开发改进的DEM提取方法。最初使用激光雷达数据从当地采石场的重合调查地面真相，从AVTIS雷达数据传感量的DEM表面提取的方法将进行调查和完善。将对照现有的AVTIS数据集（主要是蒙特塞拉特苏弗里埃山火山的数据）评价这些新方法。也可以在本地获取用于算法开发的其他数据。- 在分析现有AVTIS数据和粗糙表面散射模型的基础上开发地形分类算法，并在广泛的AVTIS数据集上进行测试，该数据集已经包括火山地形和当地获得的数据，例如阿盖尔的Rest and Be Alfful; Lomond Hills Fife; Skye的Old Man of Storr。- 利用AVTIS-2雷达在冰岛等地进行实地活动，收集冰川冰的毫米波NRCS数据，作为入射角的函数，并开发适合于雷达性能预测的经验模型。- 使用AVTIS-2收集冰川的第一批毫米波雷达DEM，并与同期获得的激光雷达（地面激光扫描）DEM进行定量比较。- 探索仪器在火山-冰和冰-海洋相互作用方面的新解释潜力[1] Macfarlane，D.G.，奥德伯特，H.M.，罗伯森检察官詹姆斯先生平克顿，H。& Wadge，G.，"使用AVTIS地面94 GHz双模式雷达/辐射成像仪绘制火山地形的地形图和热图"，IEEE Trans. Geosci。雷姆感官，51，（1），2013，pp. 455 - 472

The overall aim of this PhD is to develop the use of millimetre wave radar for applications in geosciences, focusing on volcano-glacier and ice-ocean interactions. Millimetre wave radar offers a key advantage over conventional optical survey methods in its ability to map terrain with high resolution whilst operating in conditions of reduced visibility. The AVTIS radars developed at University of St Andrews by Macfarlane & Robertson for volcano imaging [1] have demonstrated the potential for such instruments to map topographic change on volcanoes through complete obscuration (e.g. ash, clouds). In addition to topography, the millimetre wave radar can measure reflectivity and the velocity of moving targets, including high spatio-temporal resolution mapping of rainfall. DEM extraction and the discrimination between terrain types based on reflectivity, or normalised radar cross section (NRCS), will be developed and refined for improved classification of different terrain surface types. These are central to the study of volcano-glacier interactions and related hazards, which are still poorly understood (e.g. the 2010 Eyjafjallajökull eruption) as critical periods of activity during eruptions are often obscured. The AVTIS radar will elucidate changes in the volcano and glacier geometries, impacting eruption timing, magnitude or meltwater-induced mass movements e.g. lahars. The first case study will thus target ice-capped volcanoes (e.g. Iceland). The calving of icebergs at the margins of glaciers and ice sheets is critical to our understanding of the near future contribution of the Greenland Ice Sheet to sea level rise. Continuous monitoring of grounded ice margins under conditions of heavy cloud cover and precipitation is thus needed, where conventional techniques (LIDAR and time lapse photography) are rendered useless. The ability of the millimetre wave radar to generate DEMs under these conditions will be invaluable. The second stage of the project will thus be glacier mapping with the AVTIS-2 radar, which has never previously been reported in the literature. The project will follow broadly this structure: - Develop improved DEM extraction methodology using existing AVTIS data. Initially using LIDAR data from a coincident survey of a local quarry as ground truth, methods for DEM surface extraction from the AVTIS radar data sensing volume will be investigated and refined. These new methods will be evaluated against existing AVTIS datasets (mainly data from the Soufriere Hills Volcano, Montserrat). Additional data for algorithm development can also be acquired locally. - Develop terrain classification algorithms based on analysis of existing AVTIS data and rough surface scattering models, tested on the extensive AVTIS data set, which already includes volcanic terrain and locally acquired data e.g. Rest and Be Thankful, Argyll; Lomond Hills Fife; Old Man of Storr, Skye. - Gather millimetre wave NRCS data of glacier ice as function of incidence angle using the AVTIS-2 radar on field campaign to e.g. Iceland and develop an empirical model suitable for radar performance prediction. - Collect the first mm-wave radar DEMs of glaciers using AVTIS-2 and quantitatively compare with contemporaneously acquired lidar (terrestrial laser scanned) DEMs. - Explore the new interpretational potential of the instrument in terms of volcano-ice and ice-ocean interactions [1] Macfarlane, D.G., Odbert, H.M., Robertson, D.A., James, M.R., Pinkerton, H. & Wadge, G., "Topographic and thermal mapping of volcanic terrain using the AVTIS ground based 94GHz dual-mode radar/radiometric imager", IEEE Trans. Geosci. Rem. Sens., 51, (1), 2013, pp. 455 - 472.