Collaborative Research: Observing and Modeling Downslope-windstorm-type Flow in a Small-scale Crater Induced by Larger-scale Katabatic Winds

这项工作将调查下坡风暴型流（DWF），它具有重要的社会影响，但科学上知之甚少。该项目包括在亚利桑那州的巴林杰陨石坑进行为期一个月的实地考察，并使用大涡流模拟（LES）模型进行模拟。美国国家科学基金会先前资助的一个研究项目的一个偶然发现，确定了这个地方是进行这种研究的理想地点，因为在晴朗、不受干扰的夜晚，当热驱动的排水流在火山口边缘层层叠叠式地流动时，dwf就会在那里定期形成。陨石坑的边缘和周围有一个规模，可以很容易地用仪器来研究这些流动，以及导致它们形成的上游条件的变化。当接近气流的温度和风廓线发生脉动时，小圆形陨石坑盆地的逆风内壁会间歇性地产生dwf。因此，这项工作将支持在一个地点系统地调查dwf，在相对较短的时间内可以预期许多重复。2013年秋季的一项相关的野外工作将收集独特的数据，以支持分析，以回答有关地形上密度分层流产生的大气dwf的现有科学问题。将利用多个LiDAR（光探测和测距）和SoDAR（声波探测和测距）平台、系留气球探测系统、红外延时相机和地面气象仪器对大气边界层条件进行详细采样。该合作团队将进行协调的实地研究、分析和大涡模拟（LES）建模，其首要目标是确定与dwf相关的特征大气结构和演变，确定驱动dwf的斜降风的控制参数，并通过建模研究将研究结果扩展到不同大小和形状的盆地和脊，从而对dwf有更全面的了解。这项研究的智力价值在于应用新颖和创新的概念，这些概念最终将在实地经验、简短的气候学以及初步分析和模拟的基础上进行更全面的分析和建模。这些努力将促进对复杂地形中影响大气DWF发展的物理过程的理解，并有望改进模式和对这种普遍存在于世界各地山区的现象的理解。这项工作的广泛影响将包括支持本科生和研究生的培训，课堂教学模块的开发，以及博士后研究人员的早期职业发展。通过提高对大气dwf的了解，对社会产生潜在的好处，并可能应用于预报下坡风暴、空气污染扩散、一般和火灾天气预报以及气候。研究结果将通过同行评议的科学出版物、科学会议上的报告和相关网站广泛传播。

This effort will investigate downslope windstorm-type flows (DWF) that have important societal effects and are poorly understood scientifically. The program includes a one-month field program at Arizona's Barringer Meteorite Crater and simulations with a Large-Eddy-Simulation (LES) model. A serendipitous discovery in a prior NSF-funded research program identified this location as being ideally suited for such a study, as DWFs develop there regularly when thermally driven drainage flows cascade over the crater's rim on clear, undisturbed nights. The crater's rim and environs are on a scale that can be readily instrumented to investigate these flows and the changing upstream conditions that cause them to form. DWFs are produced intermittently on the upwind inner sidewall of the small, circular crater basin as pulsations occur in the temperature and wind profiles of the approaching flow. This effort will thus support a systematic investigation of DWFs at a location where many replications can be expected over a comparatively short period.An associated field effort during Autumn 2013 will collect data uniquely suited to support analyses to answer extant scientific questions about atmospheric DWFs produced by density-stratified flow over topography. Detailed sampling of atmospheric boundary layer conditions by multiple LiDAR (Light Detection And Ranging) and SoDAR (SOnic Detection And Ranging) platforms, tethered balloon sounding systems, as well as infrared time-lapse cameras and surface-based meteorological instrumentation, will be utilized. The overarching goal of the coordinated field research, analysis, and large-eddy simulation (LES) modeling to be conducted by this collaborative team is to determine the characteristic atmospheric structure and evolution associated with the DWFs, identify controlling parameters in the katabatic winds that drive DWFs and, through the modeling studies, extend the findings to basins and ridges of different size and shape to gain a more general understanding of DWFs. The intellectual merit of this research rests in application of novel and innovative concepts that will culminate in more comprehensive analyses and modeling informed by field experience, a short climatology, and initial analyses and simulations. These efforts will advance understanding of the physical processes that affect atmospheric DWF development in complex terrain, and are expected to lead to improvements in models and understanding of this ubiquitous phenomenon, which occurs in mountainous regions throughout the world.Broader Impacts of this effort will include support of undergraduate and graduate student training, development of modules for classroom teaching, and early-career development of a postdoctoral researcher. Potential benefits to society will accrue through improved understanding of atmospheric DWFs with potential applications for forecasting of downslope windstorms, air pollution dispersion, general and fire weather forecasting, and climate. Results will be widely disseminated through peer-reviewed scientific publications, presentations at scientific meetings, and related websites.