Laboratory Studies of Ice Nucleation

实验室研究将研究非均质冰成核，并提供基本数据，以改善对大气中冰形成的了解。首先，将在与气候敏感的热带对流层顶层(TTL)有关的粒子上探索冰核，最近的工作发现，主要由硫酸盐和有机化合物组成的粒子是导致冰核形成的主要类型。将研究一系列具有不同水溶性的有机化合物，以探索它们如何影响冰核。对形成玻璃固体的有机化合物的新研究将为了解寒冷的TTL中的化学提供更多的洞察力。接下来，我们将研究以大气尘埃为代表的矿物颗粒上的非均质冰成核。虽然尘埃是众所周知的大气冰核，但随着时间的推移，尘埃上形成的涂层如何影响其成核能力，目前还不确定。拉曼显微镜将被用来确定涂层的化学成分、厚度和形态如何影响冰核。最后，使用拉曼显微镜的实验将表征野外收集的气溶胶的成冰能力。大气样品上的冰核作用将被用来选择最容易冰核作用的颗粒，用于使用拉曼光谱和测绘进行详细研究。由水冰组成的卷云在任何时候都覆盖着地球表面的30%，TTL中几乎总是存在次可见的卷云。这些云层在气候系统以及控制进入平流层的水量方面发挥着重要作用。虽然卷云对气候的净影响通常是表面变暖，但云的微物理特性决定了它们对整体气候的影响。微物理特性反过来又取决于大气中冰的成核机制。除了对冰核进行基础研究外，该项目还将为学生，特别是女性学生提供获得研究和教学技能的机会，这些技能将促进他们在大气化学和物理方面的科学生涯。该项目将把本科生和研究生带进实验室，与更资深的研究人员并肩工作，从而提供一个将科罗拉多大学的研究和教学结合在一起的机会。他们获得的经验将有助于拓宽他们的视野，并为他们提供宝贵的研究经验，这些经验将对他们未来的各种职业有用。

Laboratory studies will examine heterogeneous ice nucleation and provide fundamental data to improve understanding of ice formation in the atmosphere. First, ice nucleation will be probed on particles relevant for the climate sensitive tropical tropopause layer (TTL) where recent work has identified particles composed mainly of sulfate and organic compounds as the main type responsible for ice nucleation. A range of organic compounds with different water solubility will be studied to probe how they influence ice nucleation. New studies on organic compounds that form glassy solids will provide additional insight into chemistry in the cold TTL. Next, heterogeneous ice nucleation on mineral particles representative of atmospheric dust will be studied. While dust is a well-known atmospheric ice nucleus, there is uncertainty about how coatings that form on the dust as it ages affect its ability to nucleate ice. Raman microscopy will be used to determine how the chemical composition, thickness and morphology of the coatings influence ice nucleation. Finally, experiments using Raman microscopy will characterize the ice nucleating ability of aerosols collected in the field. Ice nucleation on atmospheric samples will be used to select the particles most amenable to ice nucleation for detailed study using Raman spectroscopy and mapping.Cirrus clouds, composed of water ice, cover up to 30% of the Earth's surface at any time and sub-visible cirrus are almost always present in the TTL. These clouds play an important role in the climate system as well as in controlling the amount of water entering the stratosphere. While the net effect of cirrus clouds on climate is usually a warming at the surface, the microphysical properties of the clouds dictate their overall climatic impact. The microphysical properties depend, in turn, on the nucleation mechanism of ice in the atmosphere. In addition to performing fundamental research on ice nucleation, this project will give students, particularly women, the opportunity to gain skills in research and teaching that will further their scientific careers in atmospheric chemistry and physics. The project will provide an opportunity to integrate research and teaching at the University of Colorado by bringing undergraduates and graduate students into the laboratory to work side-by-side with more senior researchers. The experience they gain will help widen their perspective and give them valuable research experience that will be useful to them in a variety of future careers.