Collaborative Research: The Greenland Firn Aquifer Impacts on Ice Sheet Hydrology: Characterizing Volume, Flow, and Discharge

该项目将对最近偶然发现的格陵兰岛南部冰盖的积雪层中全年存在液态水的情况采取后续行动。这一发现揭示了融水的另一条路径，使对冰盖表面融化与海平面上升关系的理解变得复杂。即使是关于积雪含水层的最基本的问题仍然没有答案。本研究将探讨三个重要的研究问题：1。积雪含水层与更广泛的格陵兰水文系统之间有哪些通道和联系，该含水层对海平面上升有何影响？2.储存在格陵兰雪层含水层中的液态水的质量/体积是多少？3.含水层中水流的速度和模式是什么？这些问题将使用标准的地下水采样技术，地震测深，核磁共振，和冰芯measurement.This研究将推进知识的格陵兰雪含水层的指导下，两个端员假设，目前可能的途径，这种存储的水退出含水层。 一曰：含水层与发育良好的冰内水文网络相连，包括裂隙和冰臼，这些网络以相对恒定的速度（季节性）将部分含水层排至河床，类似于格陵兰西部的地表融化。或2：含水层主要将水储存在可用的积雪孔隙空间中，并且在孔隙空间完全饱和和/或达到导致释放事件的阈值之前不会释放水。很可能每种机制都有一定比例是相关的，这取决于冰盖上的位置。拟议的实地研究沿着当地和区域建模研究，重点是沿着海拔梯度的冰流线到黑尔海姆冰川的目的是确定每个路径的相对贡献。准确测量和预测格陵兰冰盖需要这些知识吗？目前和未来的海平面上升的贡献。此外，本研究还验证了地面水文和地震技术测量冰内水量和流量，为未来的研究提供了新的多学科技术。更广泛的影响包括：1）进一步了解格陵兰冰盖中以前未知的水储存; 2）培训两名博士后研究人员，在冰川学和积雪建模方面; 3）涉及研究生和本科生; 4）通过在格陵兰学校Kulusuk演讲告知当地社区; 5）通过既定的推广计划告知广大公众。

This project will follow up on the serendipitous recent discovery that liquid water is present year-round within the firn layer of the southern Greenland Ice Sheet. This discovery complicates understanding of the relationship of surface melting on the ice sheet to sea level rise by revealing another pathway for meltwater to take. Even the most fundamental questions about the firn aquifer remain unanswered. This proposal will address three essential research questions: 1. What are the pathways and connections of the firn aquifer with the broader Greenland hydrologic system and what is the aquifer's effect on sea level rise?2. What is the mass/volume of the liquid water stored in the Greenland firn aquifer?3. What are the rates and patterns of water flow in the aquifer?These questions will be addressed using standard groundwater sampling techniques, seismic sounding, nuclear magnetic resonance, and ice core measurements.This research will advance knowledge of the Greenland firn aquifer guided by two end member hypotheses that present possible pathways for this stored water to exit the aquifer. 1: The aquifer is connected to a well-developed englacial hydrologic network, including crevasses and moulins, that drain some portion of the aquifer at a relatively constant rate (seasonally) to the bed, similar to surface melt in western Greenland. or 2: The aquifer is primarily storing water in available firn pore space and will not release water until the pore space is completely saturated and/or a threshold is met leading to a release event. It is likely that some proportion of each mechanism is relevant depending upon location on the ice sheet. The proposed field studies along with local and regional modeling studies focused along an elevation gradient of an ice flow line into Helheim Glacier are aimed at determining the relative contribution of each pathway. This knowledge is required to accurately measure and predict the Greenland ice sheet?s present and future contribution to sea level rise. Additionally this research verifies ground hydrology and seismic techniques for measuring englacial water volume and flow providing new multi-disciplinary techniques for future research. Broader impacts include 1) gaining further understanding of a previously unknown storage of water in the Greenland Ice Sheet; 2) training two postdoctoral researchers, in glaciology and firn modeling; 3) involving graduate and undergraduate students; 4) Informing the local community by presenting at the Kulusuk, Greenland School; 5) Informing the broad public through established outreach programs.