Investigation of Subgrid-Scale Turbulence in the Atmospheric Surface Layer Using Field Measurement Data

使用现场测量数据研究大气表层亚网格尺度湍流

• 批准号: 0222421
• 负责人: Chenning Tong
• 金额: $ 37.19万
• 依托单位: Clemson University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-10-01 至 2006-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0222421&HistoricalAwards=false
• 关键词: Investigation; Subgrid; Scale; Turbulence; Atmospheric

Large-eddy simulation (LES) is an important computational method for analyzing small-scale atmospheric circulations. Depending on the density of the computational grid, LES can accurately depict eddies and vortices with scales as small as a few meters. Still smaller eddies become increasingly important at altitudes close to the ground. A fundamental problem with LES is that the eddies in the surface layer immediately next to the ground cannot be resolved and must be parameterized - that is, in calculations of the heat and momentum flux in the atmosphere near the ground, the effects of subgrid-scale (SGS) processes must be approximated. The goal of this research is to develop improved models of SGS processes for use in the atmospheric surface layer. The approach is to analyze data taken with a specially designed array of sonic anemometers during the SGS2000 field project conducted in the San Joaquin Valley, California. These data provide unique information on the time and space structure of the wind near the ground with high resolution. The objectives of the work are (1) to investigate the effects of SGS fluxes on resolvable processes by use of joint probability functions of the resolvable velocity components and the resolvable temperature and velocity; (2) to understand the relationship between SGS fluxes and the resolvable velocity and temperature. Together, these will identify characteristics of the SGS flux that are important for resolvable processes and contribute directly to LES modeling. Progress in turbulence modeling is important not only for meteorology but also for other geophysical and engineering applications.

大涡模拟（LES）是分析小尺度大气环流的重要计算方法。 根据计算网格的密度，LES 可以准确地描绘尺度小至几米的涡流和旋涡。 在接近地面的高度，更小的涡流变得越来越重要。 LES 的一个基本问题是紧邻地面的表层涡流无法解析，必须参数化，即在计算近地面大气中的热通量和动量通量时，亚网格尺度的影响(SGS) 过程必须近似。 这项研究的目标是开发用于大气表层的改进的 SGS 过程模型。 该方法是对在加利福尼亚州圣华金谷进行的 SGS2000 现场项目期间使用专门设计的声波风速计阵列采集的数据进行分析。 这些数据以高分辨率提供有关近地面风的时间和空间结构的独特信息。 这项工作的目标是 (1) 通过使用可解析速度分量以及可解析温度和速度的联合概率函数来研究 SGS 通量对可解析过程的影响； (2)了解SGS通量与可分辨速度和温度之间的关系。 总之，这些将确定 SGS 通量的特征，这些特征对于可解析过程很重要，并直接有助于 LES 建模。 湍流建模的进展不仅对气象学很重要，而且对其他地球物理和工程应用也很重要。