The Influence of Successive Thermals on Entrainment and Dilution in a Simulated Cumulus Congestus
The Influence of Successive Thermals on Entrainment and Dilution in a Simulated Cumulus Congestus
复制标题
连续热气流对模拟浓积云夹带和稀释的影响
DOI：
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发表时间：
2017
期刊：
影响因子：
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通讯作者：
S. Lasher
中科院分区：
文献类型：
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作者：
Daniel H. Moser;S. Lasher
摘要：积云经常被观察到由多个连续的热气流组成，但夹带的数值模拟尚未研究这种程度的细节。在这里，由三个连续热气流组成的理想化模拟浓积云用于分析和理解它们在维持云核心高液态水含量方面的作用，过去的一维建模研究表明，这可以最终确定其沉淀能力。夹带和脱扣是在云核心边缘以频繁的时间间隔直接计算的。夹带最大值出现在与每个热气流相关的环形环流的后部，因此是多热云生命周期中的瞬态特征。每个热气流内稀释程度最低的地块的演变表明，仅凭夹带率无法预测高液态水含量核心的侵蚀。对每个连续热插图中夹带和排出空气样本的新颖分析...
AbstractCumulus clouds are frequently observed as comprising multiple successive thermals, yet numerical simulations of entrainment have not investigated this level of detail. Here, an idealized simulated cumulus congestus consisting of three successive thermals is used to analyze and understand their role in maintaining the high liquid water content in the core of the cloud, which past 1D modeling studies have suggested can ultimately determine its ability to precipitate. Entrainment and detrainment are calculated directly at the edge of the cloud core at frequent time intervals. Entrainment maxima occur at the rear of the toroidal circulation associated with each thermal and thus are transient features in the lifetime of multithermal clouds. The evolution of the least diluted parcels within each thermal shows that the entrainment rates alone cannot predict the erosion of the high liquid water content cores. A novel analysis of samples of entrained and detrained air within each successive thermal illustr...