Study of Atmospheric Turbulence in the Stable Boundary Layer

主要目的是研究稳定分层边界层的结构的基础上的现场测量和数值模拟的结果。为此目的，将对最近两次大气边界层实验中获得的观测结果进行分析。将对这些项目期间在仪表塔和系留提升系统（TLS）上收集的湍流数据进行检查。两个数值模型：（1）一维随机模型，由A。Kerstein，和（ii）的三维大涡模拟（LES）模型，由首席研究员开发的，也将被使用。第一个模型将用于模拟在这些项目期间观测到的夜间边界层的时间转换。LES模式将被用来评估基于梯度的相似函数，该计划的具体目标是系统地提高对稳定分层边界层的理解、描述和参数化。将对从强稳定湍流到弱稳定湍流的转变进行研究。 在这些条件下，湍流统计的渐近定律将被定义。将通过开发和测试新的尺度系统和技术来改进经典的相似性方法，这将减少尺度减小和自相关的负面影响。该项目的智力价值是提高对夜间边界层过程和制度的理解，目前还没有被充分理解，也没有很好地理解，该项目更广泛的影响是将这种对稳定边界层中湍流和扩散的更好的概念理解应用于重要问题。研究结果将通过出版物和在科学会议上的介绍加以传播。 这些结果将用于开发边界层参数化，这是数值天气预报，气候模拟和空气污染研究中必不可少的。所发展的方法也可应用于对流层湍流的研究

The main objective is to study the structure of the stably stratified boundary layer based on results of field measurements and numerical simulations. For this purpose, observations obtained during two recent atmospheric boundary layer experiments will be analyzed. Turbulence data collected during these projects on instrumented towers and by the Tethered Lifting System (TLS) will be examined. Two numerical models: (i) a one-dimensional stochastic model, developed by Dr. A. Kerstein, and (ii) the three-dimensional large-eddy simulation (LES) model, developed by the principal investigator, will also be used. The first model will be used to simulate the observed temporal transformation in the nocturnal boundary layer during these projects. The LES model will be employed to evaluate gradient-based similarity functions.The specific aim of the proposed program is to systematically improve understanding, description, and parameterization of the stably stratified boundary layer. Investigations will be conducted of transitions from strong to weak stable turbulence. Asymptotic laws for turbulent statistics in these conditions will be defined. The classic similarity approach will be improved by developing and testing new scaling systems and techniques, which will reduce negative effects of diminishing scales and self-correlation.The intellectual merit of the project is improved understanding of processes and regimes in the nocturnal boundary layer, which currently are insufficiently understood and are not well-represented in current numerical models of the atmosphere.The broader impact of the project is application of this improved conceptual understanding of turbulence and diffusion in the stable boundary layer to important problems. Results will be disseminated through publications and presentations at scientific conferences. These results will be used to develop boundary layer parameterizations, which are essential in numerical weather predictions, climate simulations, and air pollution studies. The developed methods could also be applied in studies of tropospheric turbulence