Thermohygroscopic properties of biogenic particles from the sea-surface microlayer

本项目致力于对来自海面微层（SML）的生物成因气溶胶粒子的特性进行实地和实验室调查。经过两次北冰洋考察和最近在世界海洋其他地区的额外发现，这些源自sml的颗粒已成为海洋气溶胶研究的焦点，因为它们可能广泛存在，而且对它们的产生和物理化学性质缺乏了解。这种缺乏理解的部分原因是由于sml衍生材料的不稳定性质和高度复杂的组成。即将到来的北极夏季云研究(ASCOS; http://www.misu.su.se/~michaelt- /ASCOS /ASCOS。（htm）将于2008年夏季推出，提供了一个独特的机会，利用IfT开发的高灵敏度现场气溶胶仪器来表征热吸湿性颗粒的特性，作为其物理化学特性的代表。同时，ASCOS期间将收集新的sml样品，这些样品将与2001年夏季北冰洋实验（AOE-2001）、北大西洋和波罗的海的样品一起用于IfT后续的实验室实验。在这些实验室实验中，将从sml样品中产生气溶胶颗粒，以便在高达300°C和101%相对湿度的条件下进行详细的热吸湿特性表征。在最先进的批量方法允许的范围内，互补化学分析将表征不同的sml样品。通过将sml衍生颗粒暴露在气溶胶室的紫外线/可见光下，并通过蒸发sml衍生颗粒上产生的雾滴，将探索空气中sml衍生材料的稳定性。最后，将建立一个大小相关的颗粒模型来描述sml衍生颗粒的热吸湿特性和稳定性，该模型与AOE-2008的现场数据和随后的实验室结果一致。这项工作将在莱比锡大学的博士论文范围内实现。

This project is dedicated to field and laboratory investigations of the characteristics of biogenic aerosol particles derived from the sea-surface microlayer (SML). After two Arctic Ocean expeditions and additional recent findings from other parts of the world's oceans these SML-derived particles have come into the focus of marine aerosol research because of their likely widespread occurrence and because of the lack of understanding concerning their generation and physicochemical properties. Part of this lack of understanding is due to the unstable nature und the highly complex composition of SML-derived material. The upcoming Arctic Summer Cloud Study (ASCOS; http://www.misu.su.se/~michaelt- / ASCOS/ASCOS. htm) to be launched in the summer of 2008 provides a unique opportunity to use highly sensitive in situ aerosol instrumentation developed at IfT to characterize the thermohygroscopic particle properties as proxies for their physicochemical characteristics. At the same time new SML-samples will be collected during ASCOS, which, together with samples from AOE-2001 (the Arctic Ocean Experiment in summer of 2001) the North Atlantic, and the Baltic Sea, will be utilized in subsequent laboratory experiments at IfT. In these laboratory experiments aerosol particles will be generated from the SML-samples for detailed thermohygroscopic characterization up to 300°C and 101% relative humidity. Complementary chemical analyses will characterize the different SML-samples as far as state-of-the-art bulk methods allow. By exposing SML-derived particles to UV/VIS light in an aerosol chamber and by evaporating fog drops generated on SML-derived particles the stability of airborne SML-derived material will be explored. Finally a size-dependent particle model will be developed to describe the thermohygroscopic properties and stability of SML-derived particles that is consistent with both field data from AOE-2008 and with the subsequent laboratory results. The work will be realized within the scope of a Ph.D. thesis at Leipzig University.