Turbulent Structure Parameters over Heterogeneous Terrain - Implications for the Interpretation of Scintillometer Data

湍流热交换和水汽交换是局地、区域和全球能量和水分循环中必不可少的陆-气相互作用过程。闪烁测量法可以被认为是目前唯一可用的技术，用于准业务实验确定区域平均湍流通量，以验证区域大气模型模拟的通量或从几公里水平尺度的卫星图像得出的通量。电磁辐射计原理的基础是对在湍流大气中传播的电磁辐射强度波动进行定量评估，距离可达数公里。在这个项目中，我们将研究一些与几何测量的适用性有关的基本问题。将特别强调在中等不均匀地形上确定结构参数的空间（水平和垂直）和时间变异性（作为重力仪原理的基础）。该项目基本上依赖于结合实地测量（涡动协方差技术、涡动测量和空中测量）和使用大涡动模拟模型的数值模拟。通过这种组合，所提出的项目代表了世界范围内第一次尝试通过机载技术测量湍流温度和湿度场沿着路径的统计数据，并通过LES模拟结构参数沿着该路径的模式，从而提供了一个独立的评估的温度计的原则。

The turbulent exchange of heat and water vapour are essential land surface - atmosphere interaction processes in the local, regional and global energy and water cycles. Scintillometry can be considered as the only technique presently available for the quasi-operational experimental determination of area-averaged turbulent fluxes needed to validate the fluxes simulated by regional atmospheric models or derived from satellite images at a horizontal scale of a few kilometres. The scintillometer principle is based on the quantitative evaluation of intensity fluctuations of electromagnetic radiation propagating across the turbulent atmosphere over distances up to several kilometres. With the proposed project we will study some fundamental issues related to the applicability of scintillometry. Special emphasis will be put on the determination of the spatial (horizontal and vertical) and temporal variability of structure parameters (underlying the scintillometer principle) over moderately heterogeneous terrain. The project essentially relies on a coupling of field measurements (eddy-covariance techniques, scintillometry and airborne measurements) and numerical modelling using a large-eddy simulation (LES) model. With this combination the proposed project represents the worldwide first attempt both to measure the statistics of the turbulent temperature and humidity field along a scintillometer path by airborne techniques, and to simulate the pattern of the structure parameters along this path by LES thus providing an independent evaluation of the scintillometer principle.