The Role of Ice Growth/Evaporation Processes on the Ice Economy of Clouds

该项目包括一系列关于冰晶生长和蒸发的实验室实验以及对飞机收集的现有云数据的分析。 其中一组实验将模拟卷云中晶体生长的条件。 对现有云室的改进将允许温度低至-100 ℃，压力低至1毫巴，冰的过饱和度高达200%。 将对该室进行改造，以允许检查杂质，特别是氮氧化物对晶体习性的影响。 这些实验的结果将有助于理解在极端条件下的晶体生长在高大气卷云。 另一组在0 ℃左右的实验将被设计来研究与雪层融化有关的颗粒生长、融化和蒸发。 重点将放在相对于水具有高过饱和度的条件上，以模拟冰在有或没有云滴的空气中福尔斯下落和融化。 将监测电力效应和二次制冰。 CALJET和SHEBA项目使用机载“云镜”仪器获得的数据将与卷云和融化层模拟的实验室结果进行比较。

This project consists of a broad range of laboratory experiments on the growth and evaporation of ice crystals and the analysis of existing cloud data collected by aircraft. One set of experiments will simulate the conditions of crystal growth in cirrus clouds. Modifications to an existing cloud chamber will permit temperatures as cold as -100 C, pressures as low as 1 mb, and supersaturations with respect to ice as high as 200%. The chamber will be modified to permit the examination of impurities, in particular oxides of nitrogen, on crystal habit. Results for these experiments will contribute to the understanding of crystal growth at the extreme conditions in cirrus clouds in the high atmosphere. Another set of experiments at temperatures around 0 C will be designed to study aspects of particle growth, melting, and evaporation relevant to the melting layer of snow. Emphasis will be on conditions with high supersaturations with respect to water, to simulate ice as it falls and melts in air with and without cloud droplets. Electrical effects and secondary ice production will be monitored. Data from the CALJET and SHEBA projects using the airborne "cloudscope" instrument will be compared with laboratory results on both the cirrus cloud and the melting layer simulations.