Cold Fog Amongst Complex Terrain (CFACT)

复杂地形中的冷雾 (CFACT)

• 批准号: 2049100
• 负责人: Zhaoxia Pu
• 金额: $ 117.19万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-01 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2049100&HistoricalAwards=false
• 关键词: Cold; Fog; Amongst; Complex; Terrain

The project, Cold Fog Amongst Complex Terrain (CFACT), is to investigate cold fog formation in mountain valleys. Fog consists of tiny water droplets or ice crystals suspended in the air at or near the Earth’s surface and is considered as a type of low-lying cloud. Fog forms in high-elevation complex terrain as frequently as over water bodies but is less understood. Because of its impacts on visibility, fog is the second most common cause of weather-related aviation accidents after strong wind events. Fog forecasts have significant impacts on human activities, transportation, air quality, human health, and agriculture. Despite the impacts of fog and historical fog research, fog prediction remains a challenge for weather prediction because of complex interactions between land, water, and atmospheric conditions in fog formation. Poor fog forecasting skills reflect a lack of understanding of fog formation, development, and dissipation, which is the focus of the research. This study is expected to contribute to improving fog forecasting in mountainous regions, enhancing public awareness of fog-weather conditions, and information for decision-making. The project involves the participation of multiple institutions nationally and internationally with graduate and undergraduate training in both classrooms and the field.The overarching goals of the CFACT project are to 1) investigate cold fog development and environment conditions in complex terrain with latest observation technology, 2) improve microphysical parameterizations and visibility algorithms used in numerical weather prediction (NWP) models, and 3) develop data-assimilation and analysis methods for current and next-generation (e.g., sub-kilometer scale) NWP models. The field project will be conducted in Heber Valley, Utah, during January and February 2022 with deployment of a network of ground-based in-situ instruments and remote sensing platforms to obtain comprehensive measurements of thermodynamic profiling, cloud microphysics, physical and chemical properties of aerosols, and dynamics of the environment. The Weather Research and Forecasting (WRF) model with various physical parameterizations and coupled land-atmosphere data assimilation capabilities will be used to facilitate the studies for improved fog prediction with NWP models. It is anticipated that the efforts will result in 1) improved understanding of cold-fog processes in complex terrain, 2) an evaluation of the bulk nucleation conditions that affect cold-fog microphysics related to visibility prediction, 3) identification of knowledge gaps in the micro- to synoptic- scale kinematic and thermodynamic processes associated with cold-fog life cycles in heterogeneous complex terrain, 4) understanding of interactions between physical (e.g., particle growth, nucleation, condensation, radiation) and dynamic mechanisms (e.g., turbulence, vertical air velocities, and wave motions) during the lifecycle of a fog event, 5) an evaluation of how land-surface conditions, especially snow on the ground, affect near-surface and boundary-layer atmospheric processes including the critical role of the surface radiative balance in cold-fog formation and evolution, and 6) improvement of microscales to mesoscales NWP-model simulations.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.

该项目名为复杂地形中的冷雾(CFACT)，旨在调查山谷中冷雾的形成。雾由微小的水滴或冰晶组成，悬浮在地球表面或附近的空气中，被认为是一种低洼的云。雾在高海拔的复杂地形上形成的频率与在水体上形成的频率一样高，但人们对雾的了解较少。由于其对能见度的影响，雾是仅次于强风事件的第二大与天气有关的航空事故的原因。雾预报对人类活动、交通、空气质量、人类健康和农业都有重大影响。尽管受到雾和历史雾研究的影响，但由于雾形成过程中陆地、水和大气条件之间的复杂相互作用，雾预测仍然是天气预报的一个挑战。雾预报技能差反映出对雾的形成、发展和消散缺乏了解，而雾的形成、发展和消散是研究的重点。这项研究将有助于改善山区的雾预报，提高公众对雾天气情况的认识，并为决策提供信息。CFACT项目的主要目标是1)利用最新的观测技术调查复杂地形中的冷雾发展和环境条件，2)改进用于数值天气预报(NWP)模式的微物理参数化和能见度算法，3)为当前和下一代(例如，亚千米尺度)NWP模式开发数据同化和分析方法。实地项目将于2022年1月至2月在犹他州赫伯谷进行，部署一个地面现场仪器和遥感平台网络，以获得对热力学轮廓、云微物理、气溶胶的物理和化学性质以及环境动态的全面测量。天气研究和预报(WRF)模式具有各种物理参数和陆地-大气数据的耦合同化能力，将用于促进利用NWP模式改进雾预报的研究。预计这些努力将导致1)更好地理解复杂地形中的冷雾过程，2)评估影响与能见度预测有关的冷雾微观物理的整体成核条件，3)确定与非均匀复杂地形中冷雾生命周期有关的微观到天气尺度运动学和热力学过程中的知识缺口，4)理解雾事件生命周期期间物理(例如，粒子生长、成核、凝结、辐射)和动力学机制(例如，湍流、垂直空气速度和波动)之间的相互作用，5)评估地表条件，特别是地面降雪如何影响近地表和边界层大气过程，包括地表辐射平衡在冷雾形成和演变中的关键作用，以及6)微尺度到中尺度数值预报模式模拟的改进。该奖项反映了美国国家科学基金会的法定使命，并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，被认为值得支持。

项目成果

Turbulence Effects on the Formation of Cold Fog Over Complex Terrain With Large‐Eddy Simulation

• DOI: 10.1029/2022gl098792
• 发表时间: 2022-05
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: Xin Li;Z. Pu