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-奥布霍夫相似性理论（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，最近的几项研究已经确定了一些功能，是不完全符合MOST的预测，并将这些偏离的扰动外层，大尺度相干结构（以下简称为相干涡）的本地生成的活跃湍流在大气表面层（ASL）。 虽然一些研究提出了替代理论来描述这些差异，扰动ASL中的湍流结构仍然知之甚少。本计画的目的是研究对流边界层下稳定与不稳定ASL中的紊流结构，在对流边界层中相干涡与主动紊流之间会发生强烈的相互作用。将使用已经完成的能量平衡实验的数据集。更具体地说，该项目旨在：1。在大尺度相干涡旋的影响下，量化湍流结构和表征的偏差湍流结构的预测MOST在两个大气层结在白天的扰动ASL。2.研究相干涡旋如何与ASL湍流相互作用，以及它们对两种大气层结下动量、热量和水汽通量交换的贡献。3.从ASL的时间序列资料研究相干涡旋的空间结构和时间演变，以阐明相干涡旋的起源和来源。4.加强杰克逊州立大学微气象学实验室，并通过将该项目的研究活动和成果纳入课堂和教学实验室来丰富气象学课程。5.让大量非裔美国本科生和研究生参与研究活动，并鼓励他们参加研究活动。该计划将为本科生和研究生提供良好的教育和培训机会，并将大大提高杰克逊州立大学，全国最大的历史黑人学院和大学之一的大气科学教育。