Laboratory and Surface-based Studies of Atmospherically-relevant Ice Nucleating Particle Sources, Concentrations and Compositions

大气颗粒物上的冰的形成是一个基本过程，它可以通过影响降水的效率和分布的水文循环以及通过影响含冰云层对太阳辐射和热辐射的散射来影响气候。不完全了解不断变化的自然和人为影响的粒子排放对云中冰形成过程的作用，导致限制当前和预测气候影响程度的努力存在很大的不确定性。该项目将确定从土壤和植物表面到大气中的冰成核颗粒的排放量，特别是量化有机颗粒的贡献和性质，在这一组中，生物颗粒，与已知的无机全球冰成核颗粒源相比，特别是沙漠矿物尘埃颗粒。结果将适用于云，区域，天气预报和气候scales.The项目相结合的数值模拟研究冰成核过程的量化改进定义特定的冰成核颗粒类型从收集的土壤和植物样品的表面排放的大气和生物测量工具，并对识别它们的影响，在直接大气采样。将利用从区域重要生态系统收集的土壤颗粒和植物有机体进行冰成核的实验室研究。研究将特别关注美国西部和中部平原地区的土壤，植物和生态类型，气溶胶云的相互作用可能会影响水资源和严重的风暴特征，但方法和结果将为其他地区未来的陆基和机载研究提供信息。将使用多种方法来测量在不同温度下进入液滴时冻结的颗粒数量，就像它们在自然云中一样，这些结果将与总气溶胶质量和表面积有关。将应用专门的工具来表征冻结颗粒的组成，包括电子探针分析，单颗粒质谱，用于选择性去除生物和有机颗粒的热和化学处理，所有生物颗粒的基因扩增和测序，已知细菌和真菌冰成核颗粒的基因的具体量化，以及荧光生物颗粒的在线测量。这些相同的工具将被应用于检测不同的冰成核颗粒类型的存在和丰富的每体积的空气中的植物和土壤表面在收集区域之前，期间和之后的扰动风，雨，和收获。冰成核的详细和一般化的描述将从这些结果中发展应用于大气model.The更广泛的影响，这项工作涉及促进博士后教育和培训，开发和测试新的仪器和方法，对气候变化问题的结果，通过合作数值模拟研究的应用，并促进大气和生物科学之间的跨学科研究。研究结果对于气溶胶对冰云和区域及全球气候的影响具有重要意义。将通过项目网站、出版物、参加会议和科学工作组以及与科学新闻机构的公开交流来传播成果。

The formation of ice on atmospheric particles is a basic process that can impact climate through both the hydrological cycle, via influencing the efficiency and distribution of precipitation, and through impacts on the scattering of solar and thermal radiation by ice-containing clouds. Incomplete understanding of the role of changing natural and human-influenced particle emissions on ice formation processes in clouds results in large uncertainties in efforts to constrain the magnitude of current and projected climate impacts. This project will define the emissions of ice nucleating particles from soil and plant surfaces to the atmosphere, particularly to quantify the contributions and nature of organic particles, and within this group, biological particles, in comparison to known inorganic global ice nucleating particle sources, notably desert mineral dust particles. Results will be applicable toward improved quantification of ice nucleation processes in numerical modeling studies at cloud, regional, weather forecast, and climate scales.The project combines atmospheric and biological measurement tools toward defining the surface emissions of specific ice nucleating particle types from collected soil and plant samples, and toward recognition of their influence during direct atmospheric sampling. Laboratory studies will be performed of ice nucleation by collected soil particles and plant organisms subject to lofting by winds from regionally important ecosystems. Studies will have specific focus on soils, plants, and ecotypes of the intermountain West and Central U.S. Plains regions where aerosol cloud interactions may impact both water resources and severe storm characteristics, but methods and results will inform future land-based and airborne studies in other regions. Multiple methods will be used to measure the numbers of particles that freeze when they enter liquid drops at different temperatures, as they do in natural clouds, and these results will be related to total aerosol mass and surface area. Specialized tools will be applied to characterize the compositions of particles freezing, including electron microprobe analysis, single particle mass spectrometry, thermal and chemical treatments for selective removal of biological and organic particles, genetic amplification and sequencing of all biological particles, specific quantification of genes of known bacterial and fungal ice nucleating particles, and online measurements of fluorescent biological particles. These same tools will be applied toward detecting the presence and abundance of different ice nucleating particle types per volume of air in the atmosphere over plant and soil surfaces in collection areas before, during and after perturbations by wind, rain, and harvesting. Detailed and generalized descriptions of ice nucleation will be developed from these results for application in atmospheric models.The broader impacts of this work involve promoting postdoctoral education and training, development and testing of new instrumentation and methods, application of results toward climate change issues through collaborative numerical modeling studies, and fostering cross-disciplinary research between the atmospheric and biological sciences. Results are of critical importance to unresolved impact of aerosols on ice clouds and regional and global climate. Dissemination of results will occur via a project web site, publications, participation in conferences and scientific working groups and open communication with science news agencies.