Laboratory and Numerical Model Studies of Ice Formation in Clouds

这项工作涉及三个方面的冰形成， 云：碘化银冰成核气溶胶的影响; 天然冰核的测量和冰的模拟 形成卷云。 两个互补的方法将是 使用：CSU云室的实验室实验， 用数值云模型进行模拟。 实验将 模拟各种边界清晰云中冰形成过程 条件，相当于大气云。 测量自然 冰核是该设备的一个新应用;这项工作将 建立一个大型膨胀室的效用， 天然冰核的测量。 冰核过程 卷云将模拟均匀和 非均匀冻结过程 实验室实验将用于推导函数 冰成核的定量描述。 实验室 结果将与模型的结果进行比较， 将提高他们的预测能力 能力的 冬季地形云的几个个例研究 将用一个动力学微物理模型模拟播种 使用新的成核配方。//

This work addresses three aspects of ice formation in clouds: the effects of silver iodide ice nucleating aerosols; measurements of natural ice nuclei; and simulations of ice formation in cirrus clouds. Two complementary approaches will be used: laboratory experiments in CSU's cloud chambers, and simulations with numerical cloud models. The experiments will simulate ice forming processes in a variety of well-defined cloud conditions, equivalent to atmospheric clouds. Measuring natural ice nuclei is a new application of the facilities; this work will establish the utility of a large expansion chamber to make measurements of natural ice nuclei. Ice nucleation processes in cirrus clouds will be simulated for both homogeneous and heterogeneous freezing processes. The laboratory experiments will be used to derive functional quantitative descriptions of ice nucleation. The laboratory results will be compare with those of the models, and revisions to the models will be made to improve their predictive capabilities. Several case studies of winter orographic cloud seeding will be simulated with a dynamical microphysical model using the new nucleation formulations. //