In this study, a conceptual model to define convective density currents is proposed. Based on theory, observations and modeling studies, we define convective density currents as 3D coherent structures with an anomalously cold core, an adjacent wind gust, and a vertical structure made of two layers: a well-mixed one near the surface and a stratified one above. With this definition, a methodology is proposed to identify and label individual convective density currents in convection-permitting simulations. The method is applied to four distinct cloud scenes taken from a convection-permitting simulation. Our methodology reveals new dynamic, thermodynamic, and geometric features related to the density currents’ imprint on the planetary boundary layer. The method is found to be (i) relevant in distinct convective regimes, (ii) relevant in land and oceanic situations, and (iii) adapted to both Cloud Resolving Models and Large Eddy Simulations. It also provides proxies such as the number, the spatial coverage, the mean radius, and the mean velocity of convective density currents, from which a detailed analysis of their role in the life-cycle and spatial organization of convection could be performed in the near future.

中文翻译：

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对流产生的密度电流的物理定义：允许对流模拟中的检测和表征

在这项研究中，提出了定义对流密度电流的概念模型。基于理论、观察和建模研究，我们将对流密度流定义为具有异常冷核、相邻阵风和由两层组成的垂直结构的 3D 相干结构：靠近地表的混合良好的一层和分层的一层以上。根据这个定义，提出了一种在允许对流模拟中识别和标记单个对流密度电流的方法。该方法应用于从允许对流模拟中获取的四个不同的云场景。我们的方法揭示了与密度电流在行星边界层上的印记相关的新的动力学、热力学和几何特征。发现该方法 (i) 与不同的对流机制相关，(ii) 与陆地和海洋情况相关，以及 (iii) 适用于云解析模型和大涡模拟。它还提供了对流密度流的数量、空间覆盖、平均半径和平均速度等指标，从中可以详细分析它们在对流生命周期和空间组织中的作用。未来。