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

该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-冰川和冰海相互作用。与传统的光学测量方法相比，毫米波雷达具有一个关键优势，即能够在能见度较低的条件下以高分辨率绘制地形。由麦克法兰和罗伯逊在圣安德鲁斯大学开发的用于火山成像的AVTIS雷达已经证明了这种仪器在完全遮蔽（如火山灰、云层）的情况下绘制火山地形变化的潜力。除了地形外，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测绘。DEM提取和基于反射率或归一化雷达截面（NRCS）的地形类型之间的区分将被开发和改进，以改进不同地形表面类型的分类。这些是火山-冰川相互作用和相关危害研究的核心，由于火山喷发期间的关键活动时期往往模糊不清，因此人们对火山-冰川相互作用和相关危害的了解仍然很少（例如2010年Eyjafjallajökull火山喷发）。AVTIS雷达将阐明火山和冰川几何形状的变化，影响喷发时间、震级或融水引起的物质运动，如火山泥流。因此，第一个案例研究将针对冰顶火山（如冰岛）。冰川和冰盖边缘冰山的崩解对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，在云量大、降水多的条件下，需要对地面冰缘进行连续监测，而传统技术（激光雷达和延时摄影）在这种情况下就显得毫无用处了。毫米波雷达在这些条件下产生dem的能力将是无价的。因此，该项目的第二阶段将是利用AVTIS-2雷达进行冰川测绘，这在以前的文献中从未报道过。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。首先使用来自当地采石场的同步调查的LIDAR数据作为地面真相，然后将研究和改进从AVTIS雷达数据传感体中提取DEM表面的方法。这些新方法将根据现有的AVTIS数据集（主要来自Montserrat的Soufriere Hills火山）进行评估。算法开发的额外数据也可以在本地获得。-根据现有AVTIS数据和粗糙表面散射模型的分析，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取的数据，例如Rest and Be Thankful， Argyll；洛蒙德希尔斯法夫；斯托尔老人，斯凯。-利用AVTIS-2雷达在冰岛等地的野外活动中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收集冰川的第一个毫米波雷达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。-探索该仪器在火山-冰和冰-海洋相互作用方面的新解释潜力[b] Macfarlane， D.G, Odbert， H.M, Robertson， D.A, James， M.R, Pinkerton， H. & Wadge， G.，“利用AVTIS地面94GHz双模雷达/辐射成像仪进行火山地形和热成像”，IEEE Trans。Geosci。科学通报，2013,(1),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.