The rime‐splintering hypothesis of cumulus glaciation examined using a field‐of‐flow cloud model
The rime‐splintering hypothesis of cumulus glaciation examined using a field‐of‐flow cloud model
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DOI：
10.1002/qj.49710343805
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发表时间：
1977-10
影响因子：
8.9
通讯作者：
L. Randall Koenig;F. W. Murray
中科院分区：
文献类型：
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作者：
L. Randall Koenig;F. W. Murray
进行了一项数学实验来验证这样一种假设，即在某些云中出现意想不到的高浓度冰粒是由母冰粒形成时产生的小冰粒（“碎片”）引起的。实验采用轴对称二维流场模型，结合参数化液体和冰的微物理特性。云的行为，无论是宽或窄的初始液滴大小分布，有和没有分裂，进行了模拟。分裂标准是基于最近的实验室数据。发现液体到冰的快速转化是先前存在的大液滴的一个强烈的、直接的函数。云的动力特性既影响了碎片的产生，也影响了整体的冰川特征，而不管“冰增殖”机制是否存在。在有强烈上升气流和强劲增长的水平上，云凝结物转化为冰的速度比消散云区域的凝结物要慢。与没有分裂产生的模拟相比，允许分裂产生冰的模拟更接近地复制了自然界的相关观测结果。出乎意料的是，液相的特性对模拟云的动力学产生了实质性的影响。
A mathematical experiment was conducted to test the hypothesis that the occurrence of unexpectedly large concentrations of ice particles in certain clouds is caused by the production of small ice particles (‘splinters’) during the riming of mother ice particles. the experiment used an axially symmetric two-dimensional field-of-flow model incorporating parameterized liquid and ice microphysics. the behaviour of clouds, growing with either wide or narrow initial droplet size distributions, with and without splintering, was simulated. Splintering criteria were based on recent laboratory data. The rapidity of liquid to ice conversion was found to be a strong, direct function of the prior presence of large liquid drops. the dynamical properties of the clouds influenced both splinter production and also the over-all glaciating characteristics regardless of the presence or absence of an ‘ice multiplication’ mechanism. Cloud condensate at levels having strong updraughts and vigorous growth was more slowly converted to ice than condensate in regions of dissipating cloud. the simulations permitting ice generation by splintering more closely duplicated pertinent observations in nature than those without splinter production. Unexpectedly, the characteristics of the liquid phase exerted substantial influence on the dynamics of the simulated clouds.