Collaborative Research: Sublimation of Snow (SOS)

积雪在水资源中发挥着至关重要的作用，特别是对于那些从山区降雪的季节性融化中获得水的地区来说。然而，融化并不是积雪耗尽的唯一方式。雪的升华是指雪直接变成水蒸气的过程。升华的影响还不是很清楚，导致或多或少升华的具体大气条件也不是很清楚。该项目将通过在2022-23年冬季在科罗拉多州部署一套先进的仪器，帮助解决与这些主题有关的问题。这个项目的结果将是一个数据集，可以用来确定数值模式是否正确地处理升华，如果不正确，如何改进它们。研究小组将与水资源管理者等相关利益攸关方团体进行沟通，并制作短片，以公众可以理解的清晰语言解释困难的概念。学生将直接参与现场活动，从而培养下一代观测和数据分析科学家。研究团队将于2022-23年冬季在科罗拉多州壶池进行雪的升华(SOS)现场活动。雪的升华在水资源中扮演着重要的角色，但控制升华速率的物理机制还没有完全被理解。这个项目将集中于风在升华中的作用，无论是在湍流至关重要的低风条件下，还是在高风条件下，当吹入积雪因素时。SOS现场活动嵌入了美国能源部赞助的一个更大的活动，称为地面大气综合现场实验室(SAIL)，该实验室将提供雷达和激光雷达的遥感测量。SOS将贡献四个通量塔(NCAR集成地面通量系统，ISFS)用于湍流和潜热通量测量，以及一些其他仪器，这些仪器将提供积雪深度、密度和水分、土壤和积雪温度以及吹雪特征。三个关键的科学问题将被解决：是什么决定了复杂地形中雪上的近地表边界层的特征，以及这些特征是如何随着时间的推移而演变的？在一个冬季，不同的边界层制度出现的频率有多高，在每种情况下有多少雪升华，以及这如何影响总的季节质量和能量平衡？什么测量和分析策略在量化山谷中的积雪升华方面最可靠？这一奖项反映了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，被认为值得支持。

Snowpack plays a vital role in water resources, especially for regions that get water from the seasonal melt of mountain snowfall. However, melting is not the only way that the snowpack is depleted. Sublimation of snow refers to the process by which snow changes directly to water vapor. The impact of sublimation is not well understood, nor are the specific atmospheric conditions that lead to more or less sublimation. This project will help to address questions related to those topics by deploying a set of advanced instrumentation in Colorado in the 2022-23 winter season. The result of this project will be a dataset that can be used to determine whether numerical models are handling sublimation correctly, and if not, how to improve them. The research team will communicate with relevant stakeholder groups, such as water managers, and develop short videos that explain difficult concepts in clear language accessible to the general public. Students will be directly involved in the field campaign, thereby training the next generation of observational and data analysis scientists.The research team will conduct the Sublimation of Snow (SOS) field campaign in Kettle Ponds, Colorado during the 2022-23 winter season. Snow sublimation plays a significant role in water resources but the physics that govern rates of sublimation are not fully understood. This project will focus on the role of wind in sublimation, both in low-wind conditions where turbulence is crucial, and in higher-wind conditions when blowing snow factors in. The SOS field campaign is embedded within a larger DOE-sponsored campaign called the Surface Atmosphere Integrated Field Laboratory (SAIL) which will provide remote sensing measurements from radars and lidars. SOS will contribute four flux towers (NCAR Integrated Surface Flux Systems, ISFS) for turbulence and latent heat flux measurements, along with a number of other instruments that will provide snow depth, density, and water content, soil and snowpack temperatures, and blowing snow characteristics. Three key science questions will be addressed: What governs the characteristics of the near-surface boundary layer over snow in complex terrain, and how these characteristics evolve through time? Over a winter season, how frequently do different boundary layer regimes occur, how much snow sublimation occurs during each, and how does this affect the total seasonal mass and energy balance? What measurement and analysis strategies are most robust for quantifying snow sublimation in a mountain valley?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.