CAREER: Towards Better Representations of the Nocturnal Low-Level Jets in New Generation Large-Eddy and Mesoscale Models

这项工作将集中于对大气最低层的风结构进行密切协调的观测和数值研究，特别关注导致一种被称为“低空急流”(如急流，又名LLJ，它经常在春夏月份的夜间在美国中部平原上空发展)的重复性风型发展的机制。将特别注意确定环境控制措施，以确定这种提升的动量来源(因此是能源)混合到地球表面的程度，以及它对通过风力涡轮机产生的可再生能源的后续影响。研究人员的方法将包括：(1)通过德克萨斯理工学院运营的一系列现有设施(包括安装了10个离散水平的声波风速计的200米塔楼)和新获得的闪烁仪--所有这些都是更好地了解LLJ条件下近地表风廓线演变的关键--开发一个描述LLJ结构的扩展观测数据库；(2)对从LLJ水平到夜间稳定分层条件下风力涡轮机水平的间歇性垂直混合动量的湍流控制进行量化；(3)在德州理工大学发展一门名为“风力发电气象学”的新研究生课程；及(4)一项广泛的K-12推广活动，让当地学校的教师和学生接触到各种课堂和实地活动，这将大大加强小学和中学的科学教育。这个项目的一个特别新颖的方面是将“大涡模拟”方法与通过天气预报模式(WRF)进行的更传统的中尺度模拟相结合。这项工作与上述特殊观测相结合，将更好地描述(并最终实现更准确的预测)湍流事件的发生，在这些事件中，根植于低空急流中心的更强风向下向地表移动。这项工作的更广泛影响是巨大的，将包括对城市空气质量和大型涡轮机发电网络(风电场)发电能力变化的更准确预测，在这个石油价格不断上涨的时代，风力发电网络的实施正在迅速扩大。随着学生通过适当的数据可视化技术(在课堂上)和实地考察，接触到近地表风的观测和数值预报的各个方面，以更熟悉可再生能源发电系统，小学、中学和大学的教育也将得到相当大的加强。

This work will focus on a closely coordinated observational and numerical study of wind structure in the lowest layers of the atmosphere, with particular attention to mechanisms leading to development of a recurring wind pattern known as the "low level jet" (as in jetstream, aka LLJ, which frequently develops during nighttime hours over the U.S. central plains during spring/summer months). Particular attention will be directed toward identifying environmental controls on the degree to which this elevated source of momentum (and hence energy) is mixed down toward the earth's surface and its subsequent impacts on renewable energy production via wind turbines. The investigator's approach will embody a combination of: (1) development of an expanded observational database describing LLJ structure via an array of existing facilities operated by Texas Tech (including a 200 m tower mounted with sonic anemometers at 10 discrete levels) in conjunction with a newly acquired scintillometer--all of which are key to better understanding near-surface wind profile evolution under LLJ conditions; (2) numerical simulations to quantify turbulent controls on the intermittent vertical mixing of momentum from the level of the LLJ down to that of wind turbines during stably-stratified conditions typical of nighttime; (3) development of a new graduate-level course at Texas Tech University entitled "Wind Power Meteorology"; and (4) a broad K-12 outreach effort exposing teachers and students at local schools to a variety of classroom and field activities that will significantly enhance both primary and secondary science education.A particularly novel aspect of this project is inclusion of the "Large Eddy Simulation" (LES) approach in tandem with more traditional mesoscale simulations conducted via the Weather Forecasting Model (WRF). This effort, in tandem with above-mentioned special observations, will better describe the occurrence (and ultimately serve to achieve more accurate prediction) of episodes of turbulence in which stronger winds rooted aloft in the core of the LLJ mix downward toward the surface. The Broader Impacts of this work are substantial, and will include more accurate forecasts of changes in urban air quality and power generation capacity across large networks of turbine-powered electric generators ("wind farms") whose implementation is expanding rapidly in this era of mounting petroleum prices. Considerable enhancements to education at primary, secondary and university level will also occur as students are exposed to various aspects of the observation and numerical forecast of near-surface winds through suitable data visualization techniques (in the classroom) and field trips to become more familiar with renewable energy generation systems.