Collaborative Research: Snow Transport in Katabatic Winds and Implications for the Antarctic Surface Mass Balance: Observations, Theory, and Numerical Modeling

1. 对项目更广泛的意义和重要性的非技术解释，作为国家科学基金资助的公开理由。对于不是科学家或工程师的受过教育的读者来说，这部分应该是可以理解的。垂直风或排水风，在重力的作用下将高密度的空气从较高的海拔带下斜坡。虽然高山和极地地区普遍存在变暖流，但目前缺乏对这些流动的表层相似理论，这削弱了数值天气和气候预测模式的准确性。该项目是跨学科的，将为研究生和本科生提供与核心学科以外的研究人员互动的宝贵经验。此外，该项目将通过已建立的项目，通过招募来自公开大学和科罗拉多大学代表性不足群体的学生，扩大科学参与。南极冰盖通过对区域和全球大气和海洋环流的调节、淡水的储存以及对全球反照率和气候的影响，驱动着地球系统中的许多过程。了解冰盖的表面质量平衡对于预测未来海平面上升和解释冰芯记录至关重要。然而，由于缺乏一个总体的理论框架，缺乏原位观测数据集，以及缺乏准确的数值模拟工具，冰盖通过雪沉积、侵蚀和降风（在南极大部分地区持续存在）的演变仍然知之甚少。鉴于预估在南极大陆内将发生的未来气候和降雪变化，迫切需要提高对倾斜输送过程的基本认识和建模能力。该项目将利用一个多学科研究团队的专业知识（具有跨越冰冻圈科学、环境流体力学和大气科学的背景）来解决这些知识空白。项目的技术描述，说明要研究的问题，研究的目标和范围，以及要使用的方法和途径。在许多情况下，技术项目描述可能是与提案一起提交的项目摘要的修改版本。通过现场观测和直接数值模拟，该项目有望首次建立一个将湍流通量与平均垂直梯度联系起来的地表相似理论。相似理论将用于开发大涡模拟（LES）的表面边界条件，从而实现第一个精确的大涡模拟。pi将开发的数值工具将使他们能够研究雪的再分布、运输和升华之间的分配如何取决于南极洲通常遇到的环境参数（例如大气分层、地表倾斜角度和湿度剖面）。该奖项反映了美国国家科学基金会的法定使命，并通过基金会的知识价值和更广泛的影响审查标准进行了评估，认为值得支持。

1. A non-technical explanation of the project's broader significance and importance, that serves as a public justification for NSF funding. This part should be understandable to an educated reader who is not a scientist or engineer.Katabatic or drainage winds, carry high-density air from a higher elevation down a slope under the force of gravity. Although katabatic flows are ubiquitous in alpine and polar regions, a surface-layer similarity theory is currently lacking for these flows, undermining the accuracy of numerical weather and climate prediction models. This project is interdisciplinary, and will give graduate and undergraduate students valuable experience interacting with researchers outside their core discipline. Furthermore, this project will broaden participating in science through recruitment of students from under-represented groups at OU and CU through established programs.The Antarctic Ice Sheet drives many processes in the Earth system through its modulation of regional and global atmospheric and oceanic circulations, storage of fresh water, and effects on global albedo and climate. An understanding of the surface mass balance of the ice sheets is critical for predicting future sea level rise and for interpreting ice core records. Yet, the evolution of the ice sheets through snow deposition, erosion, and transport in katabatic winds (which are persistent across much of the Antarctic) remains poorly understood due to the lack of an overarching theoretical framework, scarcity of in situ observational datasets, and a lack of accurate numerical modeling tools. Advances in the fundamental understanding and modeling capabilities of katabatic transport processes are urgently needed in view of the future climatic and snowfall changes that are projected to occur within the Antarctic continent. This project will leverage the expertise of a multidisciplinary team of investigators (with backgrounds spanning cryospheric science, environmental fluid mechanics, and atmospheric science) to address these knowledge gaps.2. A technical description of the project that states the problem to be studied, the goals and scope of the research, and the methods and approaches to be used. In many cases, the technical project description may be a modified version of the project summary submitted with the proposal. Using field observations and direct numerical simulations of katabatic flow, this project is expected--- for the first time---to lead to a surface-layer similarity theory for katabatic flows relating turbulent fluxes to mean vertical gradients. The similarity theory will be used to develop surface boundary conditions for large eddy simulations (LES), enabling the first accurate LES of katabatic flow.The numerical tools that the PIs will develop will allow them to investigate how the partitioning between snow redistribution, transport, and sublimation depends on the environmental parameters typically encountered in Antarctica (e.g. atmospheric stratification, surface sloping angles, and humidity profiles), and to develop simple models to infer snow transport based on satellite remote sensing and regional climate modelsThis 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.