Secondary ice production (SIP) leads to the formation of new ice particles from preexisting ones. Besides generating ice crystals, SIP can also influence cloud characteristics, including convection, precipitation, and even radiative properties. This study examines the effect of ice crystal formation by Hallett-Mossop, fragmentation of freezing drops, and fragmentation due to ice–ice collision processes in an idealized deep convective cloud observed during the HAIC/HIWC campaign, using the 3D bin microphysics scheme DESCAM. Our results indicate that heterogeneous ice nucleation and fragmentation of freezing drops play a role during the early formation of the cloud while after that, Hallett-Mossop and ice-ice breakup processes dominate, representing 17.6 % and 81.5 % of the ice crystal production, for temperatures warmer than −30°C. For temperatures colder than −30°C, homogeneous and heterogeneous ice nucleation processes are the main contributors to ice crystal formation. The impact of each SIP process on particle size distributions is analyzed by tracking air parcel trajectories. This study also shows the effect of SIP processes on cloud development. Implementing SIP results in a decrease in cloud top altitude by around 1.5 km. Our analysis shows that this effect is caused by increased latent heat released below 11 km, resulting from a stronger vapor deposition on more numerous ice crystals. This enhances convection at lower levels but inhibits it above. Furthermore, incorporating SIP leads to 15 % decrease in total precipitation amount and 25 % reduction of intense rainfall (accumulated precipitation over 40 mm). Hence, our study emphasizes the importance of SIP mechanisms in cloud development and precipitation.

中文翻译：

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使用 3D bin 微物理模型研究深对流云中的二次冰产生：第二部分 - 对云形成和发展的影响


二次制冰 （SIP） 导致从先前存在的冰颗粒形成新的冰颗粒。除了产生冰晶外，SIP 还可以影响云的特性，包括对流、降水，甚至辐射特性。本研究使用 3D bin 微物理方案 DESCAM 研究了 Hallett-Mossop 形成冰晶、冻结液滴碎裂以及冰-冰碰撞过程对 HAIC/HIWC 活动期间观察到的理想化深对流云中冰晶碎裂的影响。我们的结果表明，异质冰成核和冻滴碎裂在云的早期形成过程中起作用，而在此之后，Hallett-Mossop 和冰-冰破裂过程占主导地位，分别占冰晶产生的 17.6% 和 81.5%，温度高于 -30°C。 当温度低于 -30°C 时，均质和非均相冰成核过程是冰晶形成的主要因素。通过跟踪空运包裹轨迹来分析每个 SIP 过程对粒度分布的影响。这项研究还显示了 SIP 流程对云开发的影响。实施 SIP 会导致云顶高度降低约 1.5 公里。我们的分析表明，这种影响是由 11 公里以下释放的潜热增加引起的，这是由于在更多冰晶上更强的气相沉积造成的。这在较低层增强了对流，但在较高层级抑制了对流。此外，加入 SIP 会导致总降雨量减少 15%，强降雨量减少 25%（累积降雨量超过 40 毫米）。因此，我们的研究强调了 SIP 机制在云开发和沉淀中的重要性。