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

1.对该项目更广泛的意义和重要性的非技术性解释，作为国家科学基金资助的公开理由。不是科学家或工程师的受过教育的读者应该能理解这一部分。卡塔巴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到斜坡上。虽然赤道气流在高山和极地地区无处不在，但目前缺乏对这些气流的表层相似理论，这削弱了数值天气和气候预测模式的准确性。这个项目是跨学科的，将为研究生和本科生提供与其核心学科以外的研究人员互动的宝贵经验。此外，该项目还将通过既定方案招收来自OU和CU代表性不足群体的学生，从而扩大对科学的参与。南极冰盖通过其对区域和全球大气和海洋循环的调节、淡水的储存以及对全球反照率和气候的影响，推动地球系统的许多过程。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，缺乏现场观测数据集，以及缺乏准确的数值模拟工具，人们对冰盖通过雪沉积、侵蚀和在赤道风(在南极大部分地区持续存在)中的输送而演变的了解仍然很少。鉴于南极大陆预计将发生的未来气候和降雪变化，迫切需要在卡塔式输送过程的基本理解和模拟能力方面取得进展。该项目将利用一个多学科调查小组的专业知识(具有冰冻圈科学、环境流体力学和大气科学的背景)来解决这些知识差距。对项目的技术描述，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，技术项目说明可能是随建议书一起提交的项目摘要的修订版。利用现场观测和对katabatic流的直接数值模拟，该项目有望-第一次-导致katabatic流的表层相似理论将湍流通量与平均垂直梯度联系起来。相似理论将被用来开发大涡模拟(LES)的表面边界条件，使第一个准确的大涡模拟成为可能。PIS将开发的数值工具将允许他们调查雪再分配、传输和升华之间的分配如何取决于南极洲典型的环境参数(例如大气分层、地表倾斜角和湿度分布)，并开发基于卫星遥感和区域气候模型来推断雪传输的简单模型。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，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.