Collaborative Research: Improving Model Representations of Antarctic Ice-shelf Instability and Break-up due to Surface Meltwater Processes

合作研究：改进地表融水过程导致的南极冰架不稳定和破裂的模型表示

• 批准号: 2213704
• 负责人: Douglas MacAyeal
• 金额: $ 6.86万
• 依托单位: University of Chicago
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-01-01 至 2025-12-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2213704&HistoricalAwards=false
• 关键词: Collaborative; Research; Improving; Model; Representations

Ice shelves are the floating extensions of glaciers on land. They surround 75 percent of Antarctica and have an important role in regulating the rate that inland glacier ice is lost to the ocean, which leads to sea-level rise. Meltwater that ponds on the surfaces of these ice shelves has been observed to cause ice shelves to flex and fracture, and, in some cases, to experience large-scale collapse events. For example, the near-complete collapse of the Larsen B Ice Shelf in 2002 is thought to have been caused by the drainage of over 2000 surface lakes during just a number of weeks. Extensive ponding is observed on many of Antarctica’s ice shelves. As atmospheric temperatures increase, surface meltwater-induced ice-shelf breakup events are expected to increase in areal extent and frequency. However, future predictions of such events lack accuracy because no large-scale ice-sheet model is able to realistically simulate the processes involved in surface-meltwater-induced ice-shelf breakup. This project aims to address the current modeling limitation by developing a new component for the continental-scale Ice-sheet and Sea-level System Model (ISSM) that will be capable of simulating surface meltwater-induced flexure, fracture, and large-scale ice-shelf break-up. By forcing the model with a suite of future climate-change scenarios the project aims to deliver more accurate estimates of Antarctica’s contribution to future global sea-level rise over the remainder of this century and beyond.To achieve the project’s ultimate step of developing a new model component for the Ice-sheet and Sea-level System Model (ISSM), the team will first develop a coupled process-scale model of ice-shelf hydrology-flow-flexure-fracture (the H3F model). This is required because the physics involved in ice-shelf collapse typically occurs on finer temporal and spatial scales than captured by continental ice-sheet models such as ISSM. Once the H3F model is developed, it will be used to quantify relationships between surface meltwater processes, ice flow, viscoelastic flexure, and hydrofracture. The team will translate these relationships to the ice-sheet scale by developing a machine-learning-leveraged statistical emulator of the H3F model. This approach towards multi-physics modeling aims to provide new inroads to the computationally challenging problem of surface meltwater-induced ice-shelf collapse at both small- and continental-scales. Broader impacts of the project will include public education and engagement through development of a children’s web application, interaction with a Chicago-based artist collective, and development of ISSM’s outreach webpage to facilitate interactive visualizations of Antarctica ice-shelf collapse events under a range of future climate scenarios.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.

冰架是陆地上冰川的漂浮延伸，它们包围着南极洲的 75%，在调节内陆冰川冰流失到海洋的速度方面发挥着重要作用，从而导致海平面上升。据观察，这些冰架的变形会导致冰架弯曲和断裂，在某些情况下，还会经历大规模的崩塌事件，例如，拉森 B 冰架几乎完全崩塌。 2002 年的冰架被认为是由 2000 多个地表湖泊在短短几周内被排水造成的。然而，未来对此类事件的预测缺乏准确性，因为没有大型冰盖模型能够真实地模拟地表融水引起的冰架所涉及的过程。该项目旨在通过开发大陆尺度冰盖和海平面系统模型（ISSM）的新组件来解决当前建模的局限性，该组件将能够模拟地表融水引起的弯曲、断裂和大面积冰崩解。通过使用一系列未来气候变化情景来模拟冰架破裂，该项目旨在更准确地估计南极洲在本世纪剩余时间及以后对未来全球海平面上升的影响。该项目的在为冰盖和海平面系统模型（ISSM）开发新模型组件的最终步骤中，该团队将首先开发冰架水文-流动-弯曲-断裂的耦合过程规模模型（H3F模型）这是必需的，因为与 ISSM 等大陆冰盖模型相比，冰架空间塌陷所涉及的物理现象通常发生在更精细的时间和尺度上。 一旦 H3F 模型开发出来，它将用于量化地表融水过程之间的关系。 ， 冰该团队将通过开发 H3F 模型的机器学习统计模拟器，将这些关系转化为冰盖尺度。这种多物理建模方法旨在为计算提供新的进展。小规模和大陆规模的地表融水引起的冰架崩塌具有挑战性，该项目的更广泛影响将包括通过开发儿童网络应用程序、与公众互动来进行公众教育和参与。总部位于芝加哥的艺术家团体，并开发了 ISSM 的外展网页，以促进在一系列未来气候气候下南极洲冰架崩塌事件的交互式可视化。该奖项授予 NSF 的法定使命，并通过使用基金会知识库的评估场景被认为值得支持优点和更广泛的影响审查标准。