International Collaboration in Chemistry: Measuring the effects of surfactants on cloud microphysics

环境化学科学计划支持教授罗纳德C。加州大学伯克利分校的科恩与法国里昂大学的芭芭拉·诺齐埃的研究小组合作，通过研究表面活性剂是否会影响云滴的生长速度来促进对云滴的理解。在地球大气层中，云滴完全是由水蒸气凝结成微米大小的气溶胶颗粒而形成的。这项研究将开发新的想法和方法来理解云滴的增长，特别是关于气溶胶和水滴中有机化学物质的混合物如何影响水滴增长率的关键问题。在里昂，研究的重点将是在环境气溶胶中发现的表面活性剂的特性。在伯克利，重点将是确定影响液滴生长和蒸发的参数，并了解模型表面活性剂以及里昂小组从环境气溶胶中提取的表面活性剂如何影响蒸发和生长。为了实现这些目标，将开发新的分析和光谱方法，包括光学陷阱、荧光各向异性衰减、拉曼测温和腔增强拉曼散射，以研究大气表面活性剂对云滴形成和增长的影响。在地球大气层中，云滴完全是由水蒸气凝结成微米大小的气溶胶颗粒而形成的。 伯克利的科恩小组和里昂的诺齐埃小组在过去几年里分别开创了研究液滴生长的新方法。这两个团队的实验技能和知识的融合是该项目的一个目标，预计将导致我们对气溶胶和云之间化学联系的理解取得独特的进展，特别是在云滴生长的关键步骤。该项目预计将大大提高我们对空气质量和气候政策决策科学依据的理解。研究结果将在科学文献中进行传播，通过各种媒体向更广泛的受众传播，并直接向加州的监管机构和政策制定者传播，PI将在旨在规划当地气候变化的会议上与他们进行非正式会晤

The Environmental Chemical Sciences Program supports Professor Ronald C. Cohen of the University of California, Berkeley, in collaboration with the research group of Barbara Noziere of the University of Lyon, France to advance understanding of cloud droplets by studying whether surfactants affect droplet growth rates. In the Earth's atmosphere, cloud droplets are formed exclusively by the condensation of water vapor onto micron-size aerosol particles. The research will develop new ideas and approaches to understanding cloud droplet growth especially with respect to the key question of how mixtures of organic chemicals in aerosol and on water droplets affect droplet growth rates. In Lyon, the focus of the research will be on the characterization of surfactants found in ambient aerosol. At Berkeley the focus will be on determining parameters that affect droplet growth and evaporation and understanding how model surfactants as well as the surfactants extracted from ambient aerosol by the Lyon group affect the evaporation and growth. To accomplish these goals, novel analytical and spectroscopic methods will be developed, including optical traps, fluorescence anisotropy decay, Raman thermometry and cavity enhanced Raman scattering, to investigate the effect of atmospheric surfactants on cloud droplet formation and growth.This project will develop and apply the next generation of laboratory experiments to study the fundamental chemistry of cloud droplet growth. In the Earth's atmosphere, cloud droplets are formed exclusively by the condensation of water vapor onto micron-size aerosol particles. The Cohen group at Berkeley and the Noziere group at Lyon have separately pioneered new approaches to studying droplet growth over the last few years. Fusion of the experimental skills and knowledge of the two teams, a goal of this project, is expected to lead to unique advances in our understanding of the chemical link between aerosol and clouds, especially at the crucial step of cloud droplet growth. This project is expected to result in significant advances in our understanding of the scientific basis for policy decisions regarding air quality and climate. The results will be communicated both in the scientific literature, to a more general audience through various media and directly to regulators and policy makers in California with whom the PI meets informally at meetings aimed at planning for climate change in the local region