A helicopter-borne radar system for Canadian glacier mass assessment

该项目将资助购买一套定制的直升机雷达系统，对厚达1公里的冰川进行成像。由于普遍缺乏冰厚数据，目前对加拿大冰川质量的估计非常不准确，而且有限的河床地形数据严重阻碍了冰川对气候变暖响应的建模。因此，我们预测加拿大冰川对海平面的贡献、快速变化的冰川（如冰川湖溃决洪水）的危害、下游水资源的可用性以及冰川质量变化对加拿大山地旅游的影响的能力是有限的。目前对冰厚和冰川床地形的估计主要是使用地面雷达系统进行的，这些雷达系统需要步行或由造雪机牵引，因此范围有限，耗时长，后勤成本高，并且在冰川裂缝地区操作危险或不可能。拟议中的直升机雷达系统将缓解这些问题，首次允许在加拿大冰川化环境中大规模、安全地收集冰层上的数据。这将有助于首次准确估计格陵兰岛和南极洲以外世界上最大的冰川地区的冰量。飞行员直升机雷达系统于2021年夏天在育空地区的圣埃利亚斯山脉进行了测试，成功地穿透了650米的冰层。拟议的系统将以该设计为基础，配备仪器，以提高定位精度，改进平台空气动力学，更好的控制和采集软件，以及雷达开发，使其能够穿透温度（熔点）冰达1000米。后者是必要的，因为稀疏的地面测量表明，育空地区和加拿大北极高地的大多数冰川深度远远超过650米。直升机雷达系统收集的数据将解决的主要研究问题是：1)在地方、区域和国家尺度上，加拿大冰川的质量是多少？2)与冰下地形和冰厚相关的加拿大冰川流速驱动因素是什么？3)未来冰川质量和动力将如何变化？高分辨率直升机雷达调查将在前五年在育空地区、加拿大高纬度北极地区和不列颠哥伦比亚省的主要冰川上进行，这些地区目前缺乏冰厚数据，直接帮助当前资助的研究项目，并为由团队成员监督的各种学生提供关键数据。在较长期（5-10年），调查将得出这三个地区的总冰川质量数据。除了项目组的直接成员外，所收集的数据还将使多个合作者受益，并为世界冰川监测局（瑞士）和政府间气候变化专门委员会等组织提供所需的全球重要数据。

This project will fund the purchase of a custom-built helicopter radar system to image glacier ice up to 1km thick. Current mass estimates of Canadian glaciers are highly inaccurate due to widespread lack of ice thickness data, and modelling of glacier response to climate warming is significantly hindered by limited bed topography data. As such, our ability to predict sea-level contributions from Canadian glaciers, hazards from rapidly changing glaciers such as glacier lake outburst floods, downstream water resource availability, and the impact that changing glacier mass will have on Canadian mountain tourism, is limited. Current estimates of ice thickness and glacier bed topography have primarily been made using ground-based radar systems, which are towed on foot or by snowmachine and therefore limited in extent, highly time-consuming,  logistically expensive to obtain, and dangerous or impossible to operate in crevassed glacier regions. The proposed helicopter radar system will alleviate these problems, allowing for large-scale, safe data collection over ice masses in glacierized environments across Canada for the first time. This will facilitate the first accurate estimate of ice mass in the world's largest glaciated area outside of Greenland and Antarctica. A pilot helicopter radar system was tested in summer 2021 in the St. Elias Mountains, Yukon, with successful ice penetration depth up to 650m. The proposed system will build on this design with instrumentation to improve positioning accuracy, improved platform aerodynamics, better control and acquisition software, and radar developments to enable penetration of temperate (melting point) ice up to 1000m. The latter is necessary, as the sparse ground-based measurements suggest that most glaciers in the Yukon and Canadian High Arctic are considerably deeper than 650m. The primary research questions that will be addressed with data collected with the helicopter radar system are: 1) What is the mass of Canada's glaciers, on local, regional and national scales?; 2) What are the drivers of Canadian glacier flow rates in relation to subglacial topography and ice thickness?; 3) How will glacier mass and dynamics change in the future? High resolution helicopter radar surveys will be carried out in the first five years at major glaciers in the Yukon, Canadian High Arctic and British Columbia, where ice thickness data are currently lacking, to directly aid current funded research projects and provide crucial data for a wide variety of students supervised by team members. In the longer term (5-10 years), surveys will derive total glacial mass data for these three regions. The data gathered will benefit multiple collaborators, in addition to direct members of the project team, and provide globally important data required by organizations such as the World Glacier Monitoring Service (Switzerland), and the Intergovernmental Panel on Climate Change.