Collaborative Research: The Demise Of The World's Largest Piedmont Glacier

马拉斯皮纳冰川位于阿拉斯加东南部海岸，是世界上最大的山前冰川，这种冰川始于山区，一直延伸到沿海平原。马拉斯皮纳冰川目前正在迅速变薄和退缩，沿着底部边缘形成了一系列前冰期湖泊。其中一些湖泊只被一条狭窄的冰碛沉积物带与开阔的海洋隔开。冰川的底部远低于海平面，目前所有的迹象都表明，即使未来气候变化不大，冰川的退缩和变薄仍将继续，而且很可能会加速。这可能是未来几十年阿拉斯加冰川损失最大的一次。随着马拉斯皮纳冰川的退缩和变薄，它将改变景观，暴露更多的岩石和冰碛，创造新的湖泊，和/或导致海岸线的重大变化，如海洋峡湾的形成。如果发生这种情况，这将是阿拉斯加和美国海岸线最大的现代变化之一，对陆地和海洋生态系统都有重大影响。这些变化也将构成国家公园系统近代史上陆地覆盖面积最大的单一变化。这项工作的主要目标是使用计算机模型来估计马拉斯皮纳冰川及其周边地区未来的样子。在冰川上和冰川周围实地收集的测量数据将提供必要的模型输入数据。这项工作将产生关于冰川物质平衡、冰速、冰厚、冰川床况、地表碎屑程度和厚度、前冰期湖泊发育和前冰期热岩溶演化的综合数据集。这些数据将被纳入一个数值模型，该模型将用于探索马拉斯皮纳冰川演变的大范围可能的未来情景。模式情景将考虑不同的气候轨迹以及模式参数的不确定性，例如与冰川下方的水文和运动有关的不确定性。具体而言，将解决以下问题：1。从海洋到冰川前沿的一条路径对灾难性的退缩至关重要吗？马拉斯皮纳的撤退是否会受到地表物质平衡的支配？模型预测的主要不确定性是什么？这项工作将有助于更好地了解在一个历史上以冰川大波动和时空变率为特征的地区，气候变化是如何与独立于气候的动态不稳定性相互作用的。虽然动态导致的退缩在沿海冰川中很常见，但在持续变暖的情况下，这些影响被放大了。马拉斯皮纳冰川位于Wrangell-St。伊莱亚斯国家公园，并有可能帮助人们设想气候变化对地球冰冻圈的潜在巨大影响。图形艺术家会将模型结果转换成引人注目的视觉效果，展示新景观的开放。通过在线信息测试实验，该项目将测试和开发外联材料，以增加游客对正在进行和预期的未来冰川变化和气候变化的了解。视觉和相关信息将成为互动展览，吸引成千上万的游客在弗兰格尔圣。伊莱亚斯国家公园游客中心和网上。此外，本项目将培养3名研究生在相关地球物理技术、现代冰盖建模方法和合作研究方面。项目成果将发表在同行评议的文献中，并在专业会议上发表。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Located on the coast of Southeast Alaska, Malaspina Glacier is the world’s largest piedmont glacier, a type of glacier that starts in the mountains and spills out onto the coastal plain. The Malaspina Glacier is currently rapidly thinning and retreating, forming a series of proglacial lakes along the bottom edge. Some of these lakes are only separated from the open ocean by a narrow band of sediment moraine. The underside of the glacier is located well below sea level and all current indications are that retreat and thinning will continue, and most likely accelerate, even with little future climate change. This has the potential to be the largest loss of ice in Alaska from one glacier in the next several decades. As the Malaspina Glacier retreats and thins it will transform the landscape, exposing more rocks and moraine, creating new lakes, and/or leading to significant changes in the coastline, such as the formation of marine fjords. If this happens, it will be one of the largest modern changes to Alaska’s and the nation’s coastline with large impacts to both terrestrial and marine ecosystems. These changes would also constitute the largest single change in terrestrial land cover in the National Park system in recent history.The main goal of this work is to use a computer model to estimate what the future could look like for the Malaspina Glacier and surrounding area. Measurements collected in the field, on and around the glacier, will provide the necessary model input data. The work will result in a comprehensive data set on glacier mass balance, ice velocity, ice thickness, glacier bed conditions, surface debris extent and thickness, proglacial lake development, and proglacial thermokarst evolution. These data will be ingested into a numerical model that will be used to explore a large range of possible future scenarios for the evolution of Malaspina Glacier. The model scenarios will account for different climate trajectories as well as uncertainties of model parameters, such as those associated with hydrology and motion at the underside of the glacier. Specifically, the following questions will be addressed:1. Is a pathway from the ocean to the glacier front critical for catastrophic retreat?2. Will the retreat of Malaspina be dominated by surface mass balance?3. What are the main uncertainties for model predictions?This work will lead to a better understanding of how climate change interacts with dynamic instabilities that are independent of climate, in an area that has historically been characterized by large glacier fluctuations and spatial and temporal variability. While dynamically caused retreats are common for coastal glaciers, these effects are amplified in the presence of ongoing warming.Malaspina Glacier is located in the Wrangell-St. Elias National Park and has the potential to help people envision the potentially dramatic effects of climate change on the Earth’s cryosphere. A graphic artist will convert the model results into striking visuals that show the opening up of a new landscape. Using an online message testing experiment, the project will test and develop outreach materials to increase visitor knowledge of ongoing and anticipated future glacier change and climate change. Visuals and associated information will become interactive exhibits that will engage thousands of visitors at the Wrangell-St. Elias National Park visitor center and online. In addition, this project will train three graduate students in relevant geophysical techniques, modern ice sheet modeling approaches, and collaborative research. The project outcomes will be published in peer-reviewed literature and presented at professional meetings.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.