Results, Code and Data for Quantitative Assessment of Stabilizing or Destabilizing Effect of Fjord Geometry on Greenland Tidewater Glaciers 1985-2020

To download and unzip this dataset, manually download the file a00_download_arcticdata.py, and then run using Python3: python a00_download_arcticdata.py ~/download_location 3 NOTE: You may have to authenticate and set the TOKEN environment variable, see the "Authentication" section of: https://arcticdata.io/catalog/api This study systematically examines the stress state of Greenland tidewater glaciers based on available surface velocities, terminus positions, ice thickness and bed elevations. The von Mises Calving Law is used to assess the contributions of fjord geometry to a glacier’s stability, or lack thereof. If a glacier’s expected calving rate increases upon terminus retreat after taking into account the empirical ocean heating relationship of, then fjord geometry contributes to instability; whereas a decrease signals a stabilizing fjord contribution. This principle is used to systematically evaluate 44 Greenland tidewater glaciers. Of those glaciers, 13 were found to have fjord geometry that currently contributes to instability; 7 with stabilizing geometry; and 24 that lacked statistical significance. Although the methodology as it currently stands is able to provide insight on a variety of already-retreating glaciers, it is only able to analyze terminus positions that have already been realized in the past. Therefore, it is unable to provide insight on historically stable glaciers, or on future terminus positions for which fjord geometry might change from stabilizing to destabilizing or vice versa. Future studies involving dynamic ice models could use the methodology presented here to address those questions. Full per-glaciers results are included. Python code to download external datasets, process / plot results and repeat this study is included, along with all datasets generated by this study.

如需下载并解压本数据集，请手动下载文件a00_download_arcticdata.py，随后通过Python3运行以下命令：python a00_download_arcticdata.py ~/download_location 3。注意：您可能需要完成身份验证并设置TOKEN环境变量，详情请参阅https://arcticdata.io/catalog/api 中的"Authentication（身份验证）"章节。本研究基于已获取的表面流速、冰舌末端（terminus）位置、冰厚与床面高程数据，系统分析了格陵兰潮汐冰川（Greenland tidewater glaciers）的应力状态。本研究采用冯·米塞斯崩解定律（von Mises Calving Law），评估峡湾（fjord）几何形态对冰川稳定性的影响程度。若在考虑经验海洋加热关系后，冰川的预期崩解速率随冰舌末端退缩而升高，则峡湾几何形态会加剧冰川不稳定性；反之，若崩解速率降低则表明峡湾几何形态具有稳定作用。基于该原理，本研究系统评估了44座格陵兰潮汐冰川。结果显示，其中13座冰川的峡湾几何形态目前会加剧不稳定性，7座具有稳定作用，剩余24座则未体现出统计学显著性。尽管当前的研究方法可对多座已发生退缩的冰川展开分析，但仅能基于已有的历史冰舌末端位置开展研究。因此，该方法无法对历史上保持稳定的冰川进行分析，也无法预测峡湾几何形态可能从稳定变为不稳定（或反之）的未来冰舌末端位置。未来可结合动态冰模（dynamic ice models）的研究工作，采用本研究提出的方法解决上述问题。本研究已包含所有单冰川完整结果，同时附带了用于下载外部数据集、处理/绘制结果及复现本研究的Python代码，以及本研究生成的全部数据集。