Organized Turbulence over Forested Landscapes: Theoretical Basis for a Low-Dimensional Transport Model

0208258Albertson了解森林景观与能量、水和碳的湍动通量之间的耦合已成为国家的优先事项，美国国家气候变化框架委员会的水和碳循环科学计划证明了这一点。本文提出了一个概念性模型来描述森林冠层与大气之间的质量和能量的湍流传输，它由两种端元流动类型组成：混合层(覆盖茂密的植被)和粗糙的壁边界层。具有不同程度稀疏植被的区域被表示为两个末端成员制度的叠加。总体目标是发展冠层下层(CSL)传输的相似理论，其中垂直传输现象通过耦合高分辨率地面特征(易于远程观测)和低分辨率大气场(如观测和模拟)来描述。该项目的结构是为了测试关于概念模型基础的三个假设。重点放在树冠形态和有组织的湍流输送之间的相互作用上。现场数据分析与大涡模拟(LES)相结合-数据提供了对现场条件的观测，而大涡模拟提供了在受控边界条件下湍流演变结构的全景。LES结果将被用来确定基本动态，并形成连贯结构的特征，用于指导随后对外地数据集的分析。湍流场的多尺度分解将与非线性时间序列分析工具配合使用，以开始开发低维模型。这种方法将为研究生和博士后提供独特的培训体验。主计长将继续招聘/培训任职人数不足的候选人。

0208258AlbertsonThe need to understand the coupling between forested landscapes and turbulent fluxes of energy, water, and carbon has become a national priority, as evidenced by both theUSGCRP's Water and Carbon Cycle Science Plans. Here, a conceptual model is proposed to describe turbulent transport of mass and energy between forest canopies and the atmosphere in terms of two end-member flow types: mixing layer (over dense vegetation) and rough walled boundary layer. Regions with varying degrees of sparse vegetation are represented as a superposition of the two end member regimes. The overarching goal is the development of a similarity theory for canopy sublayer (CSL) transport, where vertical transport phenomena are described by coupling high resolution surface features (that are readily observed remotely) and coarse resolution atmospheric fields (as both observed and modeled). The project is structured to test three hypotheses regarding the underpinnings of the conceptual model. The focus is on the interplay between canopy morphology and organized turbulent transport. Analysis of Field data is combined with Large, Eddy Simulation (LES) - with the data providing observations of field conditions and the LES providing a full view of the evolving structure of turbulence under controlled boundary conditions. The LES results will be used to identify the essential dynamics and to formulate signatures of the coherent structures that will be used to guide subsequent analysis of the field data sets. Multi-scale decompositions of the turbulence fields are to be used in concert with nonlinear time series analysis tools to begin the development of the low-dimensional model. This approach will provide a unique training experience for a graduate student and post-doc. The PI's will continue recruiting/training under-represented candidates.