Collaborative Research: Sediment and Stability: Quantifying the Effect of Moraine Building on Greenland Tidewater Glaciers

合作研究：沉积物和稳定性：量化冰碛建筑对格陵兰潮水冰川的影响

• 批准号: 2234523
• 负责人: John Jaeger
• 金额: $ 13.35万
• 依托单位: University of Florida
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2234523&HistoricalAwards=false
• 关键词: Collaborative; Research; Sediment; Stability; Quantifying

The Greenland Ice Sheet (GrIS) is presently the largest contributor of added mass to rising sea levels, recently surpassing contributions from alpine glaciers and ice caps, the Antarctic Ice Sheet and land water storage. Mass loss is concentrated at the periphery of the ice sheet where low-lying outlet glaciers drain into the warm ocean surrounding Greenland. Despite overall mass loss, outlet glaciers of the Greenland Ice Sheet have experienced significant variability in the amount of glacier-front retreat observed over the satellite era. This variability remains unexplained because there are many processes that can influence the position of the front of an outlet glacier and these environments are difficult to obtain observations in. This project aims to collect observations from the front of three outlet glaciers in Greenland where retreat variability has been observed. The goal of this project is to determine if the deposition of sediment at the ice-ocean boundary is responsible for the observed variability in glacier retreat. Further, this project will measure the rates and types of sedimentation processes present at the active glacier front as well as the past position of each glacier observed in the satellite record. The project will also take observations of basic glacier parameters that may be responsible for variations in the rates of sedimentation between glaciers.The overarching goal of this project is to understand the fundamental drivers of ice sheet change and stability through focusing on a poorly understood, observation-limited part of the system: the sediment budget. Moraine building at glacier termini may enable larger steady-state glaciers than would be possible in the absence of sediment, as is evident in high-meltwater settings (e.g., Alaska). However, processes and rates of proglacial sedimentation are poorly known, especially in Greenland, where morainal banks are abundant but where the influence of bank formation on ice sheet dynamics is unconstrained. The central hypothesis of this project is that morainal bank sedimentation can stabilize or delay retreat for some glacier systems. This project will test this hypothesis with observations of four processes that contribute to moraine building at three neighboring Greenland glaciers with sharply different dynamic histories and geometries. The project will deploy a novel remotely operated vehicle (ROV Nereid) designed for surveying and sampling in deep, ice marginal environments to obtain high-resolution geological, geophysical, and oceanographic measurements at the ice-sediment-ocean interface. This project will train graduate students, with a focus on mentorship and diversifying the geosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

格陵兰冰盖(GRIS)目前是海平面上升的最大贡献因素，最近超过了高山冰川和冰盖、南极冰盖和陆地水储存的贡献。质量损失集中在冰盖的边缘，那里低洼的出口冰川流入格陵兰岛周围温暖的海洋。尽管总体质量下降，但格陵兰冰盖的出口冰川在卫星时代观测到的冰川前缘退缩的数量发生了显著变化。这种变化仍然无法解释，因为有许多过程可以影响出口冰川前部的位置，而在这些环境中很难进行观测。该项目旨在收集格陵兰岛三个出口冰川前沿的观测数据，这些冰川已经观测到了退缩的可变性。该项目的目标是确定冰海交界处的沉积物沉积是否对观测到的冰川退缩的可变性负责。此外，该项目将测量活跃冰川前沿存在的沉积过程的速度和类型，以及卫星记录中观测到的每个冰川的过去位置。该项目还将对可能导致冰川之间沉积速率差异的基本冰川参数进行观测。该项目的首要目标是通过关注系统中一个知之甚少、观测有限的部分：沉积物预算，了解冰盖变化和稳定性的根本驱动因素。冰川终点处的冰原建筑可能会使更大的稳定状态的冰川比在没有沉积物的情况下更大，这在高融水环境(如阿拉斯加)中是显而易见的。然而，人们对冰川沉积的过程和速度知之甚少，特别是在格陵兰岛，那里有丰富的冰川河岸，但河岸形成对冰盖动态的影响不受限制。该项目的中心假设是，冰川岸滩沉积可以稳定或延缓某些冰川系统的消退。这个项目将通过对四个过程的观测来验证这一假设，这些过程有助于在三个动态历史和几何形状截然不同的相邻格陵兰冰川上形成冰雹。该项目将部署一种新型遥控运载器(ROV Nereid)，用于在深厚的冰缘环境中进行测量和采样，以在冰-沉积物-海洋界面获得高分辨率的地质、地球物理和海洋测量结果。该项目将培养研究生，重点是指导和使地球科学多样化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。