T-Rex Observational and Numerical Study of Sierra Nevada Mountain Waves and Rotors

霸王龙对内华达山脉波浪和转子的观测和数值研究

• 批准号: 0524891
• 负责人: Kenneth Kunkel
• 金额: --
• 依托单位: Nevada System of Higher Education, Desert Research Institute
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-10-01 至 2009-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0524891&HistoricalAwards=false
• 关键词: Rex; Observational; Numerical; Study; Sierra

The Principal Investigator will conduct a study of mesoscale airflow phenomena in the lee of the Sierra Nevada, including terrain-induced waves, rotors, and attendant downslope windstorms, and their interaction with cold air pools and thermally-forced flows in a deep lee-side mountain valley. This study is part of the Terrain-induced Rotor Experiment (T-REX), and builds on results and extends research conducted under a preceding Sierra Rotors study. Atmospheric rotors, intense low-level horizontal vortices that form along an axis parallel to, and downstream of, a mountain ridge crest, most frequently in conjunction with large-amplitude mountain waves, pose a significant hazard to aviation. Despite the significance of rotors, and because of their spatial complexity and intermittency, knowledge of rotor size, internal structure, turbulence intensity, and predictability is still limited. The main observational objective of this study is to document the full three-dimensional structure and temporal evolution of mountain waves and rotors under a wide range of environmental conditions and wave/rotor strengths. The research will be conducted using both field observations and numerical simulations. Comprehensive observational T-REX data sets from ground-based and airborne, in situ and remotely sensed instruments, including measurements obtained by the mesonetwork of automatic surface stations established during a precursor Sierra Rotors study, will be collected in the central portion of Owens Valley, in the lee of the southern Sierra Nevada. The southern Sierra Nevada is the tallest, steepest, quasi-linear topographic barrier in the contiguous United States. The mesonetwork surface observations will be collected before, during, and after the two-month intensive T-REX observational period, planned for early spring 2006. This study's numerical modeling effort will consist of high-resolution simulations with two state-of-the-art mesoscale numerical models, the Coupled Ocean-Atmosphere Modeling Prediction System (COAMPS) and the Weather Research Forecasting (WRF) modeling system. Dynamical explanations for the evolution, structure and interaction of rotors and waves with cold air pools and thermally forced flows, will be sought through synthesis of high-resolution state-of-the-art numerical model simulations and high-resolution observations. Additionally, longer-term records from the Owens Valley mesonetwork will be used to compile a climatology of the Sierra Nevada windstorms and patterns of thermally forced flow in Owens Valley. Intellectual merit: Improvement in understanding of airflow dynamics in complex terrain, in particular hazardous phenomena such as rotors, and the limits to their predictability. Understanding the role of upstream moisture in determining the flow response in the lee, and elucidating the role of stagnant flow in cold air pools on the dynamics and evolution of the lee side flows, including waves, rotors, and damaging windstorms. Broader impacts: Results of this research are expected to lead to improved prediction of aviation hazards associated with rotors and downslope windstorms in complex terrain. The results will be shared with regional operational forecast community including the National Weather Services offices whose regions of coverage include the lee side of the Sierra Nevada, and wider research community in form of guest lectures and seminars. The findings of the proposed research will also be incorporated into graduate courses in mesoscale meteorology at the University of Nevada Reno and the University of Zagreb, Croatia. The project will involve the education and training of at least one graduate student.

主要研究员将对内华达州山脉背风面的中尺度气流现象进行研究，包括地形引起的波浪、转子和伴随的下坡风暴，以及它们与背风面深谷中的冷空气池和热强迫流的相互作用。 本研究是地形诱导旋翼实验（T-REX）的一部分，以之前Sierra Rotors研究的结果为基础并扩展了研究范围。 大气旋翼是沿沿着平行于山脊顶部的轴线在山脊下游形成的强烈的低空水平涡流，通常与大振幅的山波一起出现，对航空构成重大危险。 尽管转子的重要性，并且由于其空间复杂性和不稳定性，转子尺寸、内部结构、湍流强度和可预测性的知识仍然有限。 本研究的主要观测目标是记录完整的三维结构和时间演变的山波和转子在广泛的环境条件和波/转子强度。研究将使用实地观察和数值模拟进行。 将在内华达州南部山脉背风面欧文斯谷中部收集来自地面和空中、现场和遥感仪器的T-REX综合观测数据集，包括在前体Sierra Rotors研究期间建立的自动地面站中间网络获得的测量数据。 内华达州南部山脉是美国本土最高、最陡的准线性地形屏障。 在计划于2006年早春进行的为期两个月的T-REX密集观测期之前、期间和之后，将收集mesonetwork表面观测结果。 这项研究的数值模拟工作将包括两个国家的最先进的中尺度数值模型，耦合海洋-大气模拟预测系统（COAMPS）和天气研究预报（WRF）建模系统的高分辨率模拟。 将通过综合高分辨率最先进的数值模型模拟和高分辨率观测，寻求对转子和波浪与冷空气池和热强迫流动的演变、结构和相互作用的动力学解释。 此外，欧文斯谷mesonetwork的长期记录将用于编制内华达州山脉风暴和欧文斯谷热强迫流动模式的气候学。智力优点：提高对复杂地形中气流动力学的理解，特别是转子等危险现象及其可预测性的限制。 了解上游水分在决定背风面气流响应中的作用，阐明冷空气池中滞流对背风面气流（包括波浪、转子和破坏性风暴）的动力学和演变的作用。更广泛的影响：这项研究的结果预计将导致改善预测的航空危险与转子和下坡风暴在复杂的地形。 这些结果将以客座讲座和研讨会的形式与区域业务预报界分享，包括国家气象局办事处，其覆盖区域包括内华达州的背风面，以及更广泛的研究界。 拟议研究的结果还将纳入内华达州里诺大学和克罗地亚萨格勒布大学的中尺度气象学研究生课程。 该项目将涉及至少一名研究生的教育和培训。