Laboratory Studies of Selected Cloud Microphysical Processes

该项目的中心是使用具有电动平衡的云室进行实验，该云室允许在可控的温度、压力和湿度条件下长时间观察单个漂浮的冰晶的生长或蒸发。压力和温度可以设置得足够低，以模拟大气中卷云的条件。将进行三组实验：(1)测量卷云中典型的冰晶的生长、蒸发和光散射特性；(2)研究液滴的冻结和从球形到晶体形状的快速演变；(3)测量晶体对碰撞时的质量和电荷转移。这项工作将有助于解决诸如冰晶习性及其对环境条件的依赖等基本问题，有助于当前对卷云气候影响的关注，并有助于更好地理解不同环境条件下冰晶的生长和蒸发。

This project is centered on experiments using a cloud chamber with an electrodynamic balance that permits the observation of individual, levitated ice crystals for long periods of time as they grow or evaporate in controlled conditions of temperature, pressure, and humidity. The pressure and temperature can be set low enough to simulate the conditions in cirrus clouds in the atmosphere. Three sets of experiments will be performed: (1) measurement of the growth, evaporation, and light-scattering properties of ice crystals typical of cirrus clouds; (2) study of the freezing of liquid droplets and the rapid evolution from spherical to crystal shape; (3) measuring the transfer of mass and electrical charge between pairs of crystals as they collide. This work will contribute to fundamental questions such as crystal habit and its dependence on environmental conditions, to current concerns about climatic effects of cirrus clouds, and to a better understanding of the growth and evaporation of ice crystals under different environmental conditions.