Ice in Clouds Experiment-Layer (ICE-L) Cloud Condensation Nuclei (CCN) Spectral Measurements

云中冰实验（Ice）是一个多研究者的项目，目的是更好地了解大气中冰的形成过程。作为调查的第一步，参与者将关注动态简单系统。他们将研究高空层云（因此称为ICE- layer cloud或ICE-L），与其他云系统相比，气溶胶和冰生成之间的关系相对简单。作为ICE-L的一部分，PI将获得云凝结核（CCN）观测，并利用这些观测来解决与ICE-L和其他科学目标相关的研究问题。从本质上讲，要了解任何云系统中的冰的产生，就必须了解所有的相变过程，包括那些涉及CCN的过程。这包括CCN对冷凝过程的影响，以及在浸没成核等领域的影响。除了有助于更好地理解层云中的微物理过程外，PI还将研究这些系统中的最大过饱和（以前没有做过），并研究这些动态简单系统中的质量调节系数。为了完成研究目标，PI将在NSF C 130研究飞机上部署一台仪器来观测CCN光谱。这和其他合作观察将使PI能够实现他的研究目标。这些测量包括传统的艾特肯CCN范围（0.1微米干溶直径）和大核范围（0.1-1微米）的精细空间分辨率和良好的过饱和(S)分辨率。只有DRI仪器才能提供全范围的S，这对于确定CCN和IN测量之间的关系是必要的。CCN的测量还可以帮助区分不同的冰核模式，因为一些模式——均匀、凝结冻结和浸入式冻结——直接涉及CCN。冰过程对从降水产生到气候问题，包括间接气溶胶效应在内的一系列大气问题具有重要意义，间接气溶胶效应是气候反馈过程中最重要的未知因素之一。

The Ice in Clouds Experiment (ICE) is a multi investigator project with the intent to better understand the process of ice initiation in the atmosphere. As a first step in this investigation, the involved participants will focus on dynamically simple systems. They will study high altitude, layer clouds (hence ICE-Layer Clouds or ICE L) where the relationship between aerosols and ice production will be relatively simple compared to other cloud systems. As part of the ICE L, the PI will obtain cloud condensation nuclei (CCN) observations and utilize these to address research problems of relevance to ICE-L and other scientific objectives. In essence, to understand the ice production in any cloud system, one must understand all phase transitional processes, including those that involve CCN. This includes the impact of CCN on condensational processes and in such areas as immersion nucleation. In addition to contributing to better general understanding of the microphysical processes in the layer clouds, the PI will investigate the maximum supersaturation in these systems (not previously done) and investigate the mass accommodation coefficient in these dynamically simple systems. To accomplish the research objectives, the PI will deploy on the NSF C 130 research aircraft an instrument to observe the CCN spectra. This and other collaborative observations will allow the PI to attack his research objectives. These measurements include fine spatial resolution as well as good supersaturation (S) resolution of both the traditional Aitken CCN range ( 0.1 micron dry soluble diameter) and the large nuclei range (0.1-1 micron). This full range of S available only with the DRI instruments is necessary to ascertain relationships between CCN and IN measurements. CCN measurements can also aide in discriminating the different modes of ice nucleation because some of the modes-homogeneous, condensation freezing, and immersion-freezing directly involve CCN. The ice process has important implications for a broad range of atmospheric topics from precipitation production to climate issues including the indirect aerosol effect, which is one of the most important unknowns of climate feedback processes.