CAREER: Towards a Better Understanding of Turbulence Structures in a Disturbed Atmospheric Surface Layer

职业：更好地理解受干扰的大气表层中的湍流结构

• 批准号: 0847549
• 负责人: Heping Liu
• 金额: $ 48.5万
• 依托单位: Jackson State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-15 至 2011-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0847549&HistoricalAwards=false
• 关键词: CAREER; Towards; Better; Understanding; Turbulence

The Monin-Obukhov similarity theory (MOST) provides numerical weather and climate models with a basis in formulating the turbulent exchange of momentum, energy, water vapor, and other scalars between the Earth's surface and the lower atmosphere. However, several recent studies have identified some features that are not fully consistent with predictions by MOST and attributed these departures to the disturbance of outer-layer, large-scale coherent structures (hereafter referred to as coherent eddies) on locally-generated active turbulence in the atmospheric surface layer (ASL). Although some studies have presented alternative theories to describe these discrepancies, turbulence structures in the disturbed ASL are still poorly understood. The objectives of this project are to study turbulence structures in the stable and unstable ASL beneath a convective boundary layer where a strong interaction between coherent eddies and active turbulence occurs. The datasets from the already completed Energy Balance Experiment will be used. More specifically, this project aims to: 1. Quantify turbulence structures under the influence of large-scale coherent eddies and characterize the deviations of turbulence structures from predictions by MOST under two atmospheric stratifications during the daytime in the disturbed ASL. 2. Investigate how coherent eddies interact with the ASL turbulence and their contributions to flux exchange of momentum, heat, and water vapor under two atmospheric stratifications. 3. Study the spatial structures and temporal evolutions of coherent eddies from time-series data in the ASL to elucidate the origins and sources of coherent eddies. 4. Enhance the Jackson State University Micrometeorology Laboratory and enrich meteorological courses through incorporating research activities and findings of this project in the classroom and teaching laboratories. 5. Involve a large number of African American undergraduate and graduate students and encourage them to take part in the research activities. This program will provide an excellent education and training opportunity for undergraduate and graduate students and will greatly enhance atmospheric sciences education in Jackson State University, one of the nation's largest historically black colleges and universities.

莫宁-奥布霍夫相似理论 (MOST) 为数值天气和气候模型提供了制定地球表面和低层大气之间动量、能量、水蒸气和其他标量的湍流交换的基础。然而，最近的几项研究发现了一些与 MOST 预测并不完全一致的特征，并将这些偏差归因于外层大尺度相干结构（以下简称相干涡流）对局部产生的主动湍流的干扰。大气表面层（ASL）。 尽管一些研究提出了替代理论来描述这些差异，但人们对受干扰的 ASL 中的湍流结构仍然知之甚少。该项目的目标是研究对流边界层下方稳定和不稳定 ASL 中的湍流结构，在该边界层中相干涡流和主动湍流之间会发生强烈的相互作用。将使用已完成的能量平衡实验的数据集。更具体地说，该项目的目标是： 1. 量化大尺度相干涡流影响下的湍流结构，并表征受扰 ASL 白天两种大气层结下湍流结构与 MOST 预测的偏差。 2. 研究相干涡流如何与 ASL 湍流相互作用以及它们对两种大气分层下动量、热量和水蒸气通量交换的贡献。 3. 利用ASL时间序列数据研究相干涡旋的空间结构和时间演化，阐明相干涡旋的起源和来源。 4. 通过将本项目的研究活动和成果纳入课堂和教学实验室，加强杰克逊州立大学微气象实验室并丰富气象课程。 5.吸引大量非裔美国本科生和研究生参与并鼓励他们参与研究活动。该计划将为本科生和研究生提供极好的教育和培训机会，并将极大地加强杰克逊州立大学的大气科学教育，杰克逊州立大学是美国历史上最大的黑人学院和大学之一。