Homogeneous ice formation in convective cloud outflow regions
Homogeneous ice formation in convective cloud outflow regions
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对流云流出区域的均匀冰形成
DOI：
10.1002/qj.3069
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发表时间：
2017
影响因子：
8.9
通讯作者：
B. Kärcher
中科院分区：
文献类型：
--
作者：
B. Kärcher
利用一个精确跟踪液滴冻结事件的谱块模式，沿沿着理想化的对流云轨迹研究了暖卷云区（230-240 K）的均匀液滴冻结。描述了新的模式，并用于研究冰的形成从快速上升（垂直速度0.6-6 m s-1）包含云凝结核（CCN）和液态水滴的空气包裹。暖卷云中的均匀冻结事件受潜热交换的影响，在初始过饱和淬火后产生最大尺寸为10-100 μm的小冰晶模式。在形成阶段，在对流云外流中均匀形成的冰晶数浓度几乎不受冰晶沉降的影响，并且对垂直速度敏感。在云凝结核在冻结之前或沿着激活成云水小滴的情况下，相对湿度的变化也会导致对云凝结核溶解度不敏感的冰数变化很大。这些结果提供了指针，如何进一步的进展，可以实现在模拟和更好地了解对流层上层冰云的形成起源于对流疏散区。
Homogeneous droplet freezing in the warm cirrus regime (230–240 K) is investigated along idealized convective cloud trajectories using a spectral parcel model developed to track droplet freezing events accurately. The novel model is described and used to study ice formation from rapidly ascending (vertical velocity 0.6–6 m s−1) air parcels containing cloud condensation nuclei (CCN) and liquid water droplets. Homogeneous freezing events in warm cirrus are affected by latent heat exchange and produce a mode of small ice crystals with maximum dimensions 10–100 μm after initial supersaturation quenching. During the formation stage, ice‐crystal number concentrations formed homogeneously in convective cloud outflow are hardly affected by ice‐crystal settling and depend sensitively on vertical velocity. In the case of CCN activation into cloud water droplets prior to or along with freezing, relative humidity variations also result in widely varying ice numbers that are insensitive to CCN solubility. These results offer pointers on how further progress can be achieved in simulating and better understanding the formation of upper tropospheric ice clouds originating from convective detrainment zones.
对流云中的准球形冰
影响因子：
3.1
作者：
Järvinen;Schnaiter;Mioche;Jourdan;Shcherbakov;Afchine;Krämer;Heidelberg;Jurkat;Schlager;Nichman;Gallagher;Schmitt;Bansemer;Heymsfield;Lawson
通讯作者：
Lawson