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

这项工作将调查具有重要社会影响但科学上知之甚少的下坡风暴型流动。该计划包括在亚利桑那州的巴林杰陨石坑为期一个月的实地计划和模拟与大涡模拟（LES）模型。 在之前NSF资助的研究计划中的一个偶然发现确定了这个位置非常适合这样的研究，因为DWF在那里定期发展，当热驱动的排水流在清晰，不受干扰的夜晚倾泻在陨石坑的边缘时。 陨石坑的边缘和周围的规模，可以很容易地仪器调查这些流动和不断变化的上游条件，导致他们的形成。 DWF间歇性地产生在小的圆形火山口盆地的逆风内侧壁上，因为接近流的温度和风廓线中发生脉动。 因此，这项工作将支持DWFs的系统调查，在一个位置，可以预期在一个相对较短的时间内，在2013年秋季相关的实地工作将收集数据，特别适合支持分析，以回答现存的科学问题，大气DWFs产生的密度分层流地形。 将利用多个激光雷达和声波雷达平台、系留气球探测系统以及红外延时照相机和地面气象仪器对大气边界层状况进行详细取样。 该协作团队进行的协调实地研究、分析和大涡模拟（LES）建模的总体目标是确定与DWF相关的特征大气结构和演变，确定驱动DWF的下吹风的控制参数，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山脊，以获得对DWF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，这些概念将最终导致更全面的分析和建模，包括实地经验，短期气候学以及初步分析和模拟。 这些努力将促进对影响复杂地形中大气环流发展的物理过程的理解，并预期将导致改进模型和对世界各地山区普遍存在的这一现象的理解，这一努力的更广泛影响将包括支持本科生和研究生培训，开发课堂教学模块，和博士后研究人员的早期职业发展。 通过提高对大气DWF的理解，将产生潜在的社会效益，这些DWF具有预测下坡风暴、空气污染扩散、一般和火灾天气预报以及气候的潜在应用。 研究结果将通过同行评审的科学出版物、在科学会议上的介绍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.