Nucleation and particle formation in the upper atmosphere
Nucleation and particle formation in the upper atmosphere
复制标题
高层大气中的成核和粒子形成
DOI：
10.1029/jd094id12p14683
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发表时间：
1989
影响因子：
--
通讯作者：
R. Keesee
中科院分区：
文献类型：
--
作者：
R. Keesee
在夏季中间层顶的高纬度地区，温度可能足够低，以至于该地区的水在环境蒸汽浓度约为百万分之一的体积下变得强烈过饱和。在过饱和状态下，水蒸气可以从气相中分离出来，形成和生长云颗粒。大气尘埃和离子被怀疑是水可以收集的主要核源。从陨星尘埃核中形成冰粒的过程被称为非均质成核。离子核促进粒子形成称为离子诱导成核。综述了这两种竞争机制的形式及其在夏季极地中层顶条件中的应用。结果表明，这两个过程都是引发夜光云形成的可行机制。然而，由于计算出的成核速率是高度不确定的，因此不能明确地确定夜光云形成的一种或另一种成核机制的优势。
In the high latitudes of the summer mesopause, temperatures can be sufficiently cold that the region becomes strongly supersaturated in water at ambient vapor concentrations around a part per million by volume. With supersaturation, water vapor can be removed from the vapor phase to form and grow cloud particles. Meteoric dust and ions are suspected to be the dominant sources of nuclei upon which water can collect. The development of ice particles from cores of meteoric dust involves a process known as heterogeneous nucleation. Particle formation promoted by ionic nuclei is called ion-induced nucleation. The formalisms for these two competitive mechanisms and their application to conditions of the summer polar mesopause are reviewed. Results suggest that both processes are feasible mechanisms for initiating noctilucent cloud formation. However, because calculated nucleation rates are highly uncertain, the predominance of one or the other nucleation mechanism for noctilucent cloud formation cannot be unambiguously established.