Collaborative Research: A New Approach to Firn Evolution using the Taylor Dome Natural Laboratory

合作研究：利用泰勒穹顶自然实验室研究杉木进化的新方法

• 批准号: 2024163
• 负责人: Kaitlin Keegan
• 金额: $ 38.59万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-15 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2024163&HistoricalAwards=false
• 关键词: Collaborative; Research; New; Approach; Firn

The transformation of snow into firn and then glacial ice is a fundamental process in glaciology. Understanding it is critical for many applications including the conversion of satellite altimetry measurements into ice-sheet mass changes—a key measure of glacier response to climate change. Better process understanding is also critical for determining the difference in the age of ice and the gas trapped within it. This difference complicates the age-dating of ice cores. Despite its importance, the transformation of snow into firn and then ice is still poorly understood and current predictive models have limited applicability. This project aims to develop a physically based firn-compaction model for the glaciological community. The team will take the first steps toward this goal through a set of field and laboratory experiments combined with model developments. The fieldwork will be at Taylor Dome in Antarctica. This project will introduce a new combination of firn datasets designed to lead to the development of next-generation, physics-based firn models. Advances in ice-core science and satellite altimetry demand firn models that can reliably simulate firn evolution in a range of climatic conditions, in a changing climate, and on long- and short-time scales. Current firn-compaction models are largely based on a steady-state assumption and tuned to particular geographical locations. Advancing beyond these models requires (1) measuring current firn-compaction rates (2) measuring grain-scale microstructures that play a crucial role in firn compaction, and (3) quantifying processes driving evolution of those microstructures. To decouple firn’s sensitivities to accumulation and temperature, the team will measure in situ strain rates by two independent methods and observe trends in microstructure in cores from sites spanning the accumulation gradient at Taylor Dome, while maintaining the same average temperature. The team will assess the ability of phase-sensitive radar to remotely measure firn-compaction rates, potentially simplifying future in situ measurements. This work will create a roadmap for collecting future microstructural data spanning key areas of temperature-accumulation space and simplify future collaborations through the availability of an open-source Community Firn Model.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.

雪转化为冰雪，然后转化为冰川冰是冰川学的一个基本过程，了解这一过程对于许多应用至关重要，包括将卫星测高测量结果转化为冰盖质量变化——这是冰川对气候变化响应的关键指标。尽管冰芯年龄测定很重要，但对于确定冰和其中所含气体的年龄差异也至关重要，但目前对雪转变为冰和冰的过程仍知之甚少。预测模型该项目旨在为冰川界开发基于物理的压实模型，该团队将通过一系列现场和实验室实验以及模型开发，迈出实现这一目标的第一步。该项目将引入新的冰雪数据集组合，旨在开发下一代基于物理的雪冰模型。冰芯科学和卫星测高的进步需要能够可靠模拟的雪冰模型。当前的凝结压实模型主要基于稳态假设，并且需要适应特定的地理位置。 (1) 测量当前的凝结压实率 (2) 测量在凝结压实中起关键作用的晶粒级微观结构，以及 (3) 量化驱动这些微观结构演化的过程以消除凝结的敏感性。对于堆积和温度，该团队将通过两种独立的方法测量原位应变率，并观察跨越泰勒圆顶堆积梯度的岩心微观结构的趋势，同时保持相同的平均温度。该团队将评估相能力。这项工作将创建一个路线图，用于收集跨越温度累积空间关键区域的未来微观结构数据，并通过开源社区 Firn 的可用性简化未来的合作。该奖项体现了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，NSF 的法定使命被认为值得支持。