Collaborative Research: EAGER: Design, Fabrication, and Performance Evaluation of a Marine Aerosol Generator for Shipboard Deployment

海洋表面气泡破裂产生的海洋气溶胶是地球气候系统中的一个主要过程，对对流层的物理化学演变和对上层海洋生物地球化学的反馈具有重要影响。可靠的海洋气溶胶特征是评估随后物理化学演变和反馈的性质和规模的关键先决条件。然而，新鲜的海洋气溶胶通过与光和活性气体的相互作用被迅速改变，并被注入含有来自多种来源的机械产生的气溶胶和相关反应产物的大气中，以及来自成核和生长路径的次生气溶胶。因此，根据对周围环境气溶胶的测量，很难明确地揭示新生海洋气溶胶的物理化学性质和全球意义。几年前，在美国国家科学基金会的支持下，纽约州立大学环境科学与林业学院和弗吉尼亚大学的研究人员制造、测试并成功地在百慕大部署了一台新型的大容量气溶胶发生器，以确定整个相关尺寸分布(在80%相对湿度下，直径为0.013至15？m)的新生海洋气溶胶的产生、特征和光化学演化。合乎逻辑的下一步是在海上的船只上部署一个强化版的发生器，以评估海洋有机物组成和浓度对相应的海洋气溶胶的物理化学特征和演化的影响，以及由此产生的对表层海洋的反馈。在这个项目中，同一研究团队将与斯克里普斯海洋研究所的同事一起在船上部署发电机。研究的目标是：(1)建造和实验室测试海洋气溶胶发生器的强化版本，(2)在海上的船舶上部署和操作该发生器，以及(3)评估由此产生的数字尺寸分布的代表性。原有的发电机将进行改装，使其适合在海上部署。它将于2010年春末或夏初部署在北大西洋一艘中型到大型机遇船扇尾上的避难所里。气溶胶将在一定范围内从喷嘴产生气泡速率和下降的水流速率。将在全尺寸分布(在80%RH时直径为0.13至15？m)上量化尺寸分辨的数值生产通量。更广泛的影响：结果将提供一种很好的刻画能力，用于评估表层海洋对初级海洋气溶胶的大小分辨成分和通量的影响，通过海洋颗粒有机物的光化学转化产生的活性微量气体的形态和数量，以及这些途径在海洋空气、表面海洋生物地球化学和地球气候的多阶段化学和物理演变中的相关影响。因此，该项目将直接促进研究海洋气溶胶的化学和物理演化及其对气候的影响的国家和国际方案，以及研究大气对上层海洋生物地球化学动力学的作用。特别是，这项技术有望与国际和国家表面海洋低层大气研究(SOLAS)有关。该项目还将有助于培养一名学生和博士后研究员。

Production of marine aerosols by bursting bubbles at the ocean surface is a major process in the Earth's climate system, with important implications for the physiochemical evolution of the troposphere and feedbacks on upper ocean biogeochemistry. Reliable characterization of marine aerosols is a critical prerequisite for evaluating the nature and magnitude of subsequent physiochemical evolution and feedbacks. However, fresh marine aerosols are rapidly modified via interaction with light and reactive gases and are injected into an atmosphere containing mechanically produced aerosols and associated reaction products from multiple sources and secondary aerosols from nucleation and growth pathways. Consequently, it is extremely difficult to unequivocally deconvolute the physiochemical properties and global significance of nascent marine aerosols based on measurements of ambient aerosols. Several years ago with NSF support, researchers at the SUNY College of Environmental Science and Forestry and the University of Virginia fabricated, tested, and successfully deployed a novel high-capacity aerosol generator at Bermuda to determine the production, characteristics, and photochemical evolution of nascent marine aerosols over the full relevant size distribution (0.013 to 15 ìm diameter at 80% RH). The logical next step is to deploy a hardened version of the generator on a ship at sea to evaluate the influence of marine organic matter composition and concentration on corresponding physiochemical characteristics and evolution of marine aerosol and the resulting feedbacks on the surface ocean. In this project, the same research team will be joined by colleagues at the Scripps Institution of Oceanography to deploy the generator on a ship. The research objectives are: (1) To construct and lab-test a hardened version of the marine aerosol generator, (2) to deploy and operate the generator on a ship at sea, and (3) To evaluate the representativeness of resulting number size distributions. The original generator will be modified to make it suitable for deployment at sea. It will be deployed in a shelter on the fantail of a medium- to large-size ship of opportunity in the North Atlantic during late spring or early summer 2010. Aerosols will be generated over a range of bubble rates and falling water flow rates from the nozzle. Size-resolved number production fluxes will be quantified over the full size distribution (0.13 to 15 ìm diameter at 80% RH). Broader Impacts: Results will provide a well-characterized capability for evaluating the influences of the surface ocean on the size-resolved composition and flux of primary marine aerosols, the speciation and magnitude of reactive trace gas production via photochemical transformation of marine-derived particulate organic matter, and the related influences of these pathways in the multiphase chemical and physical evolution of the marine air, surface ocean biogeochemistry, and Earth's climate. Consequently, the project will contribute directly to national and international programs investigating the chemical and physical evolution of marine aerosols and their related climatic implications as well as studies on understanding the role of the atmosphere on the upper ocean's biogeochemical dynamics. In particular this technology promises to be relevant to the international and national Surface Ocean Lower Atmosphere Study (SOLAS). The project will also contribute to the education of a student and post doctoral fellow.