Satellite volcanic ash cloud detection and quantification

火山灰已被证明对民用和军用航空的运作都有深远的影响。航空使用的空域通过两种主要工具进行操作管理：由火山和气象源项驱动的平流扩散弥散模型和卫星遥感。前者提供了对飞行规划者至关重要的预测，但前向预测增加了不确定性。后者虽然不完美，但至少提供了可用于验证预测的快照。卫星图像的一个主要问题是，任何观测都是沿着视线进行整合的。当我们从安全飞行阈值过渡到基于剂量的危害管理方法时，三个维度的观察变得至关重要。这项活动的主要目的是为布里斯托尔大学的立方体卫星研制一种热红外成像仪器，该仪器将能够在三维空间上绘制和重建火山灰云。该相机将以“瞄准并凝视”（手电筒）模式使用，利用多个视角拍摄火山灰云的三维结构。博士课程将首先根据之前在布里斯托尔与卢瑟福-阿普尔顿实验室合作开展的工作，对科学和任务要求进行评估，然后详细阐述航天器成像仪的概念设计。一旦概念设计最终确定，使用现成组件的面包板的详细设计将最终确定。设计将需要机械、电气、光学和软件分析，并将尽可能以现有产品为基础。这种面包板将被制造、测试和小型化，然后在气球上进行高度测试，并在中美洲至少一座喷发的火山上空搭载无人机。图像数据将使用SLAM等3D重建技术进行处理，该技术目前由安德鲁·卡尔韦博士的计算机科学小组从光学图像中开发出来。这项工作与亚瑟·理查兹教授和汤姆·理查森博士领导的喀斯喀特项目中正在规划的火山无人机成像研究有关，可能有资格获得该项目的资助。研究的问题将是：是否有可能使用2个波长的微型天基热像仪提供火山火山灰云的三维重建？

Volcanic ash has been proved to have a profound effect on the operation of both civil and military aviation. Airspace used by aviation is managed operationally using two primary tools: advection-diffusion dispersion models, driven by volcanic and meteorological source terms and satellite remote sensing. The first offers a prediction, vital for flight planners, but forward projection increases uncertainty. The latter, whilst being imperfect, provides snapshots that, at the very least, may be used to validate predictions. One of the major problems with satellite imagery is that any observations are integrated along the line of sight. As we transition from safe-to-fly thresholds to a dose-based approach to hazard management observations in three dimensions become critical. The primary purpose of this activity is to develop a thermal infrared (TIR) imaging instrument for a University of Bristol CubeSat that will be able to map and reconstruct ash clouds in three dimensions. The camera would be used in a 'point and stare' (flashlight) mode to use multiple viewing angles to image the three-dimensional structure of the ash cloud. The PhD will initially comprise of an assessment of the science and mission requirements, based upon previous work undertaken at Bristol in collaboration with the Rutherford-Appleton Laboratory, and then the elaboration of a conceptual design for the spacecraft imager. Once the conceptual design is finalised, a detailed design of a breadboard using off the shelf components will be finalised. The design will require mechanical, electrical, optical and software analysis and will be based as far as possible on existing products. This breadboard will be built, tested and miniaturised to be flown on a balloon for altitude testing and on a UAV over at least one erupting volcano in Central America. The image data will be processed using 3D reconstruction techniques such as SLAM, currently being developed from optical imagery by Dr. Andrew Calway's group in computer science. This work is linked to research on drone imaging of volcanos being planned as part of the CASCADE programme led by Professor Arthur Richards and Dr Tom Richardson and may be eligible for funding under this programme. The research question will be: is it possible to provide 3D reconstruction of a volcano ash cloud using a miniature space-based thermal camera in 2 wavelengths?