The Growth of Ice Hydrometeors in Atmospheric Clouds

大气云中冰水凝物的增长

• 批准号: 8718221
• 负责人: Richard Turco
• 金额: $ 32万
• 依托单位: University of California-Los Angeles
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1988
• 资助国家: 美国
• 起止时间: 1988-03-15 至 1990-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=8718221&HistoricalAwards=false
• 关键词: Growth; Ice; Hydrometeors; Atmospheric; Clouds

Large ice particles play a central role in the physics of clouds and precipitation, especially in deep convective clouds. Two processes are important for the formation of large ice particles, namely, the clumping and riming processes. The clumping processes produces snow aggregates which may serve as the embryos of graupel and hails. The graupel and hails then grow by riming and recycling through dry and wet growth stages. In the riming process, latent heat will be released which may influence the cloud dynamics. The impacts of these processes depend very much on the ice particle growth rates. Unfortunately, our previous understanding of the ice growth process is mostly qualitative. The main difficulty lies in the facts that ice particles have complicated shapes and thus complicated hudrodynamical behavior and that the motions are unsteady. Under this grant, Professor Wang will use the cloud tunnel at the University of California, Los Angles to conduct experiments of ice crystal aggregation, and also carry out theoretical computations of ice crystal motion in air. Professor Wang is competent and well qualified to carry out the work.

大冰粒在云和降水的物理过程中发挥着核心作用，特别是在深对流云中。对于大冰粒的形成，有两个过程是重要的，即凝块过程和边缘过程。凝聚过程产生了雪团聚体，这可能是小雨和冰雹的胚胎。然后，冰雹和冰雹通过干燥和潮湿的生长阶段进行轮流和循环生长。在结圈过程中，潜热会被释放出来，这可能会影响云的动力学。这些过程的影响在很大程度上取决于冰粒的生长速度。不幸的是，我们之前对冰生长过程的理解大多是定性的。主要的困难在于冰粒具有复杂的形状和复杂的流体动力学行为，并且运动是不稳定的。根据这项拨款，王教授将利用加州大学洛杉矶分校的云隧道进行冰晶聚集实验，并对冰晶在空气中的运动进行理论计算。王教授胜任而且完全有资格开展这项工作。