Origin and Transport Properties of Coherent Structures in the Planetary Boundary Layer

行星边界层相干结构的起源和输运特性

• 批准号: 9216189
• 负责人: Richard Lindzen
• 金额: $ 16.55万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-04-01 至 1995-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9216189&HistoricalAwards=false
• 关键词: Origin; Transport; Properties; Coherent; Structures

The object of this research is the investigation of the origin and transport properties of coherent structures in the planetary boundary layer (PBL) using transient development theory. Previous theoretical work on this topic has been limited to the investigation of the modal instabilities and these studies confirm that coherent structures in the form of rolls, often revealed as cloud streets, are produced most efficiently under convectively unstable conditions. Recent work on transient non-modal development of unstratified laboratory flows demonstrates that coherent structures develop robustly in flows possessing no modal instabilities. In this project, transient development theory will be applied for the first time to convectively stable and unstable viscous shear flows. The initial disturbances that lead to the largest energy growth will be determined through the employment of a variational method. The structure and evolution of these disturbances will be studied, along with their dependence on the Richardson, Reynolds, and Prandtl number. Transport properties associated with the second order exchange process will also be studied. Because the structures evolve in time, the second order correlations will be obtained as mean quantities over the life cycle of the dominant perturbations from initial growth to ultimate decay. This study addresses issues important to further progress in understanding tracer transport, air-sea interaction, organization of cloud streets, and parameterization of heat and momentum in NWP and climate models.

本文的研究对象是对中国传统文化的起源进行考察 和传输性质的相干结构在行星 边界层（PBL）瞬态发展理论。 先前 关于这一主题的理论工作仅限于 模态不稳定性的调查，这些研究证实 这种连贯的结构以卷的形式出现， 云街是在对流条件下最有效地产生的 不稳定的条件。 瞬态非模态的最新研究 非分层实验室流动的发展表明， 相干结构在不具有模态的流动中稳健地发展 不稳定性 在这个项目中，瞬态开发理论将 首次应用于对流稳定和不稳定 粘性剪切流 最初的扰动导致了 最大的能源增长将取决于就业 变分法 它们的结构和演化 干扰将被研究，沿着他们的依赖 Richardson，Reynolds，and Prandtl number. 输运性质 与第二订单交换过程相关联的还将是 研究了 因为结构是随时间演化的， 相关性将作为整个寿命期间的平均量获得 从初始增长到最终增长的主导扰动周期 腐烂 本研究报告讨论了对在以下方面取得进一步进展至关重要的问题： 了解示踪剂输送、海气相互作用、组织 数值预报中的热量和动量参数化 气候模型。