Resolvable-and Subgrid-Scale Measurements in the Atmospheric Surface Layer

大气表面层的可分辨和亚网格尺度测量

• 批准号: 9704740
• 负责人: John Wyngaard
• 金额: $ 39.85万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-12-15 至 2001-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9704740&HistoricalAwards=false
• 关键词: Resolvable; Subgrid; Scale; Measurements; Atmospheric

Abstract/Wyngaard ATM-9704740 Large-eddy simulation (LES) has become t he modeling method of choice in micrometeorological research. Nonetheless its performance in the surface layer suffers because of inadequate numerical resolution and heavy reliance on the precision of the subgrid-scale (SGS) model there. Until recently, little attention has been focused on these deficiencies in the surface layer, probably for two reasons. First, experimental limitations make it difficult to produce data for thorough testing of LES. No direct measurements of the resolvable-scale fields that LES predicts have been reported, for example. Second, the weaknesses of the traditional SGS models in the surface layer have not been documented in much detail. Measurements of resolvable- and subgrid-scale atmospheric turbulence in the atmospheric surface layer for the purpose of testing and improving SGS closures for LES are proposed here. Recent studies indicate major weaknesses of the widely used Smagorinsky SGS model near the surface. A new experimental technique is proposed whereby a lateral array of sensors is used to measure two-dimensionally filtered turbulence variables in the atmospheric surface layer. The preliminary studies presented here, which demonstrate the potential of the technique, will be extended in the proposed studies. Resolvable and SGS variables will be measured in the surface layer over a range of ABL states, from nearly neutral to highly convective, and shall be analyzed to study resolvable and subgrid-scale dynamics in detail. The resulting data and new physical insight will be coupled with parallel program using direct numerical simulation and LES data to provide the necessary impetus for the development of improved SGS models for surface-layer turbulence. The proposed program is part of a coordinated effort in a multi- disciplinary research group at the Penn State University directed at analysis and improvement of SGS modeling through combined numerical simulation and field measurement. The present studies will provide benchmark data for the development of remote sensing techniques for the measurement of filtered turbulence in the surface layer.

摘要/Wyngaard ATM-9704740 大涡模拟（LES）已成为微气象研究中的首选模拟方法。 尽管如此，由于数值分辨率不足和严重依赖亚网格尺度（SGS）模型的精度，它在表层的性能受到影响。 直到最近，很少有人关注这些缺陷的表面层，可能有两个原因。 首先，实验的局限性使得很难产生数据进行彻底的测试LES。 例如，没有直接测量LES预测的可分辨尺度场的报道。 第二，传统SGS模型在表层的弱点没有被记录在 很多细节。 测量可分辨和亚网格尺度大气湍流在大气表面层的目的是测试和改进SGS封闭LES这里提出。 最近的研究表明，广泛使用的Smagorinsky SGS模型在地表附近的主要弱点。 提出了一种新的实验技术，即横向阵列的传感器被用来测量二维过滤湍流变量在大气表面层。 这里提出的初步研究，证明了该技术的潜力，将在拟议的研究中扩展。 可分辨和SGS变量将在一系列ABL状态下的表层进行测量，从近中性到高度对流，并将进行分析，以详细研究可分辨和亚网格尺度动力学。 由此产生的数据和新的物理洞察力将与并行程序使用直接数值模拟和LES数据提供必要的推动力改进SGS模型的发展，表层湍流。 该计划是宾夕法尼亚州立大学一个多学科研究小组协调努力的一部分，该研究小组旨在通过结合数值模拟和现场测量来分析和改进SGS建模。 目前的研究将提供基准数据的遥感技术的发展，用于测量过滤湍流在表层。