Laboratory study of immersion and evaporative droplet freezing in the Leipzig Aerosol and Cloud Interaction Simulator

莱比锡气溶胶与云相互作用模拟器中浸没和蒸发液滴冻结的实验室研究

• 批准号: 33647816
• 负责人: Professor Dr. Jost Heintzenberg
• 金额: --
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2007
• 资助国家: 德国
• 起止时间: 2006-12-31 至 2011-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/33647816?language=en
• 关键词: Laboratory; study; immersion; evaporative; droplet

Ice formation in clouds influences all major cloud characteristics of interest: precipitation formation, interactions with radiation, latent heat release and cloud dynamics, chemical processes, charge separation, water vapor content, icing potential, gas and particle scavenging water redistribution, and others. Yet, it is poorly understood, because historic measurements in clouds have lacked the resolution to adequately sample early ice in clouds or the nuclei that influence its formation and because particle/droplet histories are not well characterized. Systematic laboratory studies are required to advance our understanding. Whereas such studies cannot elucidate all ice-related cloud processes we expect the new Leipzig Aerosol Cloud Interaction Simulator LACIS to be able to simulate accurately the processes of immersion and evaporative droplet freezing, which is the subject of the present proposal. For the study of these processes dedicated optical sensors need to be developed for LACIS in order to determine droplet freezing and accompanying particle characteristics. Consequently, the first part of the project covers the development of two new optical instruments for LACIS. The second part of the project focuses on the modification of LACIS for the study of immersion and evaporative droplet freezing, experiments with different well-characterized aerosol/cloud systems and the interpretation of the experimental results with a numerical model of LACIS. From these interpretations microphysical expressions and/or parameterizations for immersion and evaporation freezing processes can be evaluated/developed and made available for use in large scale models.

云中冰的形成影响所有主要的云特征：降水形成、与辐射的相互作用、潜热释放和云动力学、化学过程、电荷分离、水蒸气含量、结冰潜力、气体和颗粒清除水的再分布等。然而，它是知之甚少，因为历史上的云测量缺乏足够的样本在云中的早期冰或影响其形成的核的分辨率，因为粒子/液滴的历史没有得到很好的表征。需要进行系统的实验室研究来提高我们的认识。尽管这些研究不能阐明所有与冰有关的云过程，但我们希望新莱比锡气溶胶云相互作用模拟器LACIS能够准确地模拟浸没和蒸发液滴冻结的过程，这是本提案的主题。为了研究这些过程，需要为LACIS开发专用的光学传感器，以确定液滴冻结和伴随的颗粒特性。因此，该项目的第一部分包括为LACIS开发两种新的光学仪器。该项目第二部分的重点是修改LACIS，用于研究浸没和蒸发液滴冻结，用不同的特征良好的气溶胶/云系统进行实验，并用LACIS的数值模式解释实验结果。从这些解释的微物理表达式和/或参数化的浸泡和蒸发冻结过程可以评估/开发，并提供用于大尺度模型。