Collaborative Research: Boundary-Layer Influences on Mountain Waves and Rotors

这个合作研究项目是国际T-REX（地形诱导旋翼实验）的一部分，该实验旨在提高对内华达山脉以东欧文斯谷重力波诱导旋翼和背风波的理解。该奖项支持的研究将通过关注欧文斯山谷边界层的日结构和演化及其与山波和旋翼形成的关系，为整体T REX的实现做出贡献。本文的研究目标是：1)欧文斯谷深层山边界层与背风波和旋涡形成的相互作用；2)波浪/旋涡流与山谷风系统的相互作用，包括日热驱动流、沟道流和山谷冷池的湍流侵蚀；3)欧文斯谷风暴事件的气候学及其与天气天气事件的关系。这些目标将通过观察、分析和建模来实现。数据分析将包括欧文斯山谷的案例研究和气候分析，并将受益于研究人员在之前对其他山谷和盆地的调查中获得的见解。中尺度气象模式将用于解释观测结果，验证假设，并提供对物理机制的进一步了解。实现这些目标所需的数据将作为T-REX野外实验的一部分收集，该实验将于2006年3月至4月进行。首席研究员将协助规划和执行现场实验，并使用sodar/RASS，能量预算站和50个温度数据记录仪网络进行必要的测量，作为综合T-REX测量网络的一部分。主要研究人员将使用T-REX数据以及从欧文斯山谷收集的长期常规数据，NCEP从1979年到2003年每小时的区域再分析数据，以及来自塞拉转子和塞拉波项目的数据。T-REX野外实验将同时提供欧文斯谷边界层和高空背风波/旋翼条件的测量数据，其中包括大量连续运行的原位和遥感设备。在两个月的实验期间发生的不同程度的耦合将首次使人们能够全面研究高层扰动对山谷边界层的影响，以及边界层演化对背风波/转子特性的影响。以前对山谷边界层的研究几乎完全集中在未受干扰的条件下。这些实验还将首次对深谷中的沟道流动和山谷冷空气池顶部的湍流侵蚀进行全面评估。此外，风气候学分析将侧重于确定导致山谷大风事件的天气条件，并提高对大风事件的双模态季节性分布的理解，这与落基山脉中部的大风事件有很大不同。智力优势：该研究将促进对波浪和非波浪日影响深谷温度和风场演化的物理过程的认识和理解。这种知识的增加有望提高模型充分捕捉波/转子及其与边界层动力学相互作用的能力。这将改善美国西部和世界各地的天气预报。这项工作探索了创新的方法和概念，并结合了对先前数据的分析、气候学分析、与其他气候环境的数据进行比较、收集新数据和数值模拟来获得理解。更广泛的影响：通过提议将研究整合到大学教学中，通过对本科生和研究生的支持，通过促进研究者/学生的多样性，促进更广泛的社会影响。项目成果将通过同行评审的科学出版物和报告广泛传播，并通过提高对复杂地形边界层演变的理解，对社会有潜在的好处，并可能应用于空气污染扩散、天气预报和气候。

This collaborative research project is as part of the international T-REX (Terrain- Induced Rotor Experiment), which is designed to improve understanding of gravity-wave induced rotors and lee waves in the Owens Valley east of the Sierra Nevada range. The research supported under this award will contribute to the achievement of the overall T REX by focusing on the diurnal structure and evolution of the boundary layer in the Owens Valley and its relation to mountain wave and rotor formation. The objectives of the this research are to investigate: 1) interactions between the mountain boundary layer in the deep Owens Valley and the formation of lee waves and rotors, 2) the interaction of wave/rotor flows and valley wind systems including diurnal thermally driven flows, channeled flows, and turbulent erosion of valley cold pools, and (3) the climatology of windstorm events in the Owens Valley and its relationship to synoptic weather events. These objectives will be met through observations, analysis, and modeling. The data analyses will involve both case study and climatological analyses in the Owens Valley and will benefit from insights gained by the investigators in their previous investigations of other valleys and basins. A mesoscale meteorological model will be used to interpret the observations, verify hypotheses, and provide further insight into physical mechanisms. The data required to meet these objectives will be collected as part of the T-REX field experiment to be conducted in March-April 2006. The Principal Investigators will assist in the planning and execution of the field experiment and make necessary measurements using a sodar/RASS, an energy budget station, and a network of 50 temperature data loggers as part of a integrated T-REX measurement network. The Principal Investigators will use the T-REX data along with longer-term routinely collected data from the Owens Valley, NCEP 3-hourly regional reanalysis data from 1979 through 2003, and data from the Sierra Rotor and Sierra Wave Projects. The T-REX field experiment, with its large component of continuously operating in situ and remote sensing equipment, will provide concurrent measurements of both the Owens Valley boundary layer and the lee wave/rotor conditions aloft. The different degrees of coupling that occur within the two-month experimental period will allow, for the first time, a comprehensive study of the effects of upper level disturbances on the valley boundary layer, and the effects of boundary layer evolution on lee wave/rotor characteristics. Previous studies of valley boundary layers have focused almost exclusively on undisturbed conditions. The experiments also will allow the first comprehensive evaluation of channeled flows in deep valleys and turbulent erosion at the top of valley cold air pools. Additionally, wind climatology analyses will focus on determining the synoptic conditions that lead to high wind events in the valley and on gaining an improved understanding of the bi-modal seasonal distribution of the high wind events, which are significant different from high wind events in the Central Rocky Mountains. Intellectual Merit: The proposed research will advance knowledge and understanding of the physical processes that affect temperature and wind field evolution in a deep valley on both wave and nonwave days. This increase in knowledge is expected to lead to improvement in the ability of models to adequately capture waves/rotors and their interaction with boundary layer dynamics. This will lead to improvements in weather forecasts for the western U.S. and throughout the world. The work explores innovative approaches and concepts and uses a combination of analyses of prior data, climatological analyses, comparison with data from other climate settings, collection of new data and numerical modeling to gain understanding. Broader Impacts: Broader societal impacts are promoted through the proposed integration of the research into university teaching, through the support of undergraduate and graduate students and through the promotion of investigator/student diversity. Project results will be widely disseminated through peer reviewed scientific publications and presentations, and the results have potential benefits to society through improved understanding of complex terrain boundary layer evolution with potential applications for air pollution dispersion, weather forecasting and climate.