Turbulence interactions in Earth's atmospheric boundary layer: A scale-crossing approach to disclose transport processes near the surface

地球大气层和陆地通过双向交换过程相互调节。天气和气候预报模型是建立在对这种相互作用的机械性理解之上的。在大气边界层湍流较发达的情况下，预报和理论效果良好，但对于更稳定的情况，预报和理论变得不可靠。当对流的贡献减弱时，例如在夜间，大气稳定是非常常见的。需要补充理论来描述在稳定情况下促进湍流混合的机制，这首先需要方法的演变来观察和分类地表附近的(非)湍流过程。该项目旨在汇集新的方法来观测和描述(稳定的)大气边界层中知之甚少的近地表过程。利用一个高分辨率的现场传感立方体(20x20x5m)，在一个遥感虚拟盒子(500x500x1000m)内，我们可以同时观测空间和时间上的运动和温度结构。这种尺度交叉方法是解释大气边界层中近地面发现的间歇、混合和空间不均匀运动的关键。其次，将新的随机数据挖掘方法应用于这些真实生活数据，以表征(非)湍流事件以及这些原因的湍流混合。科学上的优点是一种地面制动方法，用于验证流体动力学和地球系统模型，这有助于更好地理解我们生活的陆地-大气界面。

The Earth's atmosphere and land regulate each other through bi-directional exchange processes. Weather and climate forecast models are built on a mechanistic understanding of that interaction. The forecast and theory work well in case of well-developed turbulence in the atmospheric boundary layer, but become unreliable towards more stable conditions. Atmospheric stability is very common when the contribution of convection diminishes, for example at night. Complementary theory is needed to describe the mechanisms that contribute to turbulent mixing in the stable case, which first requires an evolution of methodologies to observe and classify the (non-)turbulent processes near the surface. This project aims to bring together novel methods for the observation and characterization of the weakly understood near-surface processes in the (stable) atmospheric boundary layer. With a high-resolution in-situ sensing cube (20x20x5m) inside a remotely-sensed virtual box (500x500x1000m) we can observe motion and temperature structures simultaneously in space and time. This scale-crossing approach is key to elucidate the intermittent, mixed and spatially heterogeneous motions found near the surface in the atmospheric boundary layer. Second, novel stochastic data-mining methodologies are applied to these real-life data for a characterization of (non-)turbulent events and the turbulent mixing these cause. The scientific merits are a ground-braking approach for the validation of fluid-dynamic and earth-system models, that contributes to an improved understanding of the land-atmosphere interface we live in.