Collaborative Research: RUI: Frontal Ablation Processes on Lake-terminating Glaciers and their Role in Glacier Change

世界各地的冰川正在迅速变化，以应对气候变暖。终止于水中的冰川通常比终止于陆地上的冰川更薄，退缩得更快，因为它们通过水线以下的融化和冰山的断裂而失去冰。虽然许多过去的研究人员研究了终止于海洋的冰川的运作，但很少有人关注终止于湖泊的冰川以及这两种类型的冰川如何发挥不同的功能。在我们的项目中，我们将研究一组终止于湖泊的三个冰川;收集有关冰川本身，它们终止于湖泊以及冰川和湖泊之间移动的沉积物的信息。研究人员将与来自阿拉斯加土著科学与工程项目（ANSEP）以及朱诺冰原研究项目（JIRP）的学生合作，以确定由于这些湖泊，有多少额外的冰正在流失，以及冰流失对未来几十年冰川变化的影响有多大。在全球范围内，冰川末端的湖泊在过去几十年中迅速增长。然而，目前尚不清楚湖泊的增长是否是对冰川退缩的被动反应，这主要是由大气条件的变化（气温升高和/或冬季降雪量下降）驱动的，或者湖泊本身是否通过增加额外的冰损失来推动这种退缩。我们的团队汇集了一位冰川学家，一位海洋学家和一位北极地球系统建模师，以量化通过冰山生产和水下融化在三个大型冰川上流失的冰量，这些冰川将朱诺冰原排干，最终流入湖泊。调查人员将使用声纳系统和船上的探头以及安装在船上的仪器收集对湖泊状况（深度、温度、悬浮泥沙浓度）的短期和长期观测。研究人员还将利用地面雷达、GPS系统和卫星观测来测量冰川冰的厚度和速度。这些数据集将被输入计算机模型，以估计有多少额外的冰正在失去由于湖泊，这将如何改变在未来，以及有多少湖泊的存在将改变冰川的整体冰损失在21世纪世纪。这些信息将帮助我们了解未来几十年全球冰川变化的速度，从而更好地管理下游生态系统和水资源，并提高气候变化的适应能力。除了科学目标之外，该项目还将通过与本科生项目合作，发展计算研讨会，扩大地球科学界的代表性，从而加强STEM人才队伍。该奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Glaciers around the world are changing rapidly in response to warming temperatures. Glaciers that end in water often thin and retreat faster than those ending on land because they lose ice through melt below the waterline and through the breaking off of icebergs. While many past researchers have studied the workings of glaciers ending in the ocean, very few have focused on glaciers that end in lakes and how these two types of glaciers might function differently. In our project, we will study a set of three glaciers that end in lakes; collecting information about the glaciers themselves, the lakes they end in, and the sediment moving between the glacier and lake. The investigators will work with students from the Alaska Native Science and Engineering Program (ANSEP) as well as the Juneau Icefield Research Program (JIRP) to identify how much extra ice is being lost due to these lakes and how much that ice loss matters for how the glaciers will change over the coming decades.Globally, lakes at the end of glaciers have grown rapidly over the past decades. However, it remains unclear whether lakes are growing as a passive response to glacier retreat that is largely driven by changing atmospheric conditions (warming air temperature and/or declining winter snowfall), or whether the lakes themselves are driving this retreat by enabling extra ice loss. Our team brings together a glaciologist, an oceanographer, and an Arctic earth system modeler to quantify the amount of ice lost through iceberg production and underwater melt on three large glaciers draining the Juneau Icefield that end in lakes. The investigators will collect both short- and long-term observations of conditions in the lake (depth, temperature, suspended sediment concentration) using a sonar system and probes cast from a boat, as well as buoy-mounted instruments. The investigators will also measure glacier ice thickness and speed using ground-based radar, GPS systems, and satellite observations. These datasets will be fed into computer models to estimate how much additional ice is being lost due to the lake, how this will change in the future, and how much the lake’s presence will alter the glacier’s overall ice loss over the 21st century. This information will help us understand how fast glaciers across the world will change over the coming decades, which will enable better management of downstream ecosystems and water resources, as well as promoting climate change resilience. In addition to the science objectives, the project will strengthen the STEM workforce by partnering with undergraduate programs to develop computational workshops and broaden representation within the earth science community.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.