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.

雪转化为积雪和冰川冰是冰川学中的一个基本过程。 了解它对于许多应用都是至关重要的，包括将卫星测高测量转换为冰盖质量变化-冰川对气候变化反应的关键措施。 更好地理解过程对于确定冰和其中气体的年龄差异也是至关重要的，这种差异使冰芯的年龄测定变得复杂。尽管它的重要性，雪转化为积雪，然后冰仍然知之甚少，目前的预测模型具有有限的适用性。该项目旨在为冰川学界开发一个基于物理的积雪压实模型。 该团队将通过一系列现场和实验室实验以及模型开发，朝着这一目标迈出第一步。实地考察将在南极洲的泰勒圆顶进行。 该项目将介绍一种新的组合的积雪数据集，旨在导致下一代，基于物理学的积雪模型的发展。冰芯科学和卫星测高技术的进步需要能够可靠地模拟在一系列气候条件下、气候变化中以及在长时间和短时间尺度上的积雪演变的积雪模型。目前的积雪压实模型主要是基于一个稳定状态的假设，并调整到特定的地理位置。超越这些模型需要（1）测量当前的积雪压实速率（2）测量在积雪压实中起关键作用的颗粒尺度微观结构，以及（3）量化驱动这些微观结构演变的过程。为了消除积雪对积累和温度的敏感性，该团队将通过两种独立的方法测量原位应变率，并观察泰勒穹积累梯度站点核心微观结构的趋势，同时保持相同的平均温度。该小组将评估相敏雷达远程测量积雪压实率的能力，这可能会简化未来的现场测量。这项工作将为收集未来温度累积空间关键领域的微观结构数据创建一个路线图，并通过开源社区Firn模型的可用性简化未来的合作。该奖项反映了NSF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。