Impact of African Dust on Cloud Properties During ICE-T Using On-line Single Particle Mass Spectrometry

该项目涉及2011年7月在加勒比海地区进行的云中冰实验--热带场战役(ICE-T)期间，在NSF/NCAR C-130研究飞机上部署一个机载气溶胶飞行时间质谱仪(A-ATOFMS)。将使用单粒子质量光谱特征进行大气冰核(IN)的现场测量，以确定这些云中冰核的来源。提供给云的气溶胶的组成将与云中凝结核(CCN)和IN残留物的组成进行比较，以确定哪些粒子源被浓缩为IN。另一个ATOFMS将在波多黎各的热带山地云雾森林中进行持续的气溶胶测量，这是波多黎各大学协调的大型地面研究的一部分。将对气溶胶的大小和成分以及云水和降水化学进行测量，以获得关于该区域气溶胶-云相互作用的可变性的信息。最后，受控实验室研究将测量矿物粉尘以及陆地和海洋来源的生物微粒的IN特性。冰核实验的一个主要目标是证明在给定的条件下，直接冰核测量(S)，以及单个粒子化学和大小的测量，可以用来预测选定的云中由成核机制形成的冰粒的数量。地面、飞机和实验室研究旨在更好地了解不同来源对加勒比地区云特性和降水的影响，包括远程输送的非洲沙尘、生物粒子、海洋喷雾和污染。现场测量IN的组成和来源，结合其他微物理、气象学和热力学测量，将提供前所未有的对不同粒子来源的云影响的洞察，特别是关注尘埃和生物粒子在热带地区温暖(-15摄氏度)海洋云中冰核形成过程中的作用。这些结果将有助于更好地理解来自世界上最大来源地区的尘埃的矿物学和老化如何影响加勒比地区的云和降水，加勒比地区是一个高度研究不足的地区，具有敏感的生态系统。研究结果将被用于约束和改进模型，以更好地预测全球范围内的冰云形成。学生将接受化学、物理、建模、大气化学和仪器开发等学科的培训。作为ICE-T的一部分，这些学生将有机会与来自多个学校和组织的广泛的科学家和学生互动，以及在波多黎各和维尔京岛地区。将开发一个侧重于这些研究的网页，并在桦树水族馆举办一个公开展览，重点关注冰云及其如何在大气中形成并影响气候和天气。一个流动展览将被带到当地的小学，向孩子们传授云和气候的知识。波多黎各大学的学生将在活动期间协助测量，以及随后对结果进行分析和整合。项目成果将用于教育公众有关气溶胶化学如何影响区域和全球降水模式和气候。

This project involves deploying an Airborne Aerosol Time of Flight Mass Spectrometer (A-ATOFMS) aboard the NSF/NCAR C-130 research aircraft during the Ice in Clouds Experiment - Tropical Field Campaign (ICE-T) in the Caribbean region in July 2011. In situ atmospheric ice nucleus (IN) measurements will be made using single particle mass spectral signatures to determine the sources of ice nuclei within these clouds. The composition of aerosols feeding the clouds will be compared with those of cloud condensation nucleus (CCN) and IN residuals within clouds to determine which particle sources are enriched as IN. An additional ATOFMS will perform continuous aerosol measurements in a tropical montane cloud forest in Puerto Rico as part of a large ground-based study coordinated by the University of Puerto Rico. Measurements of aerosol size and composition, as well as of cloud water and precipitation chemistry, will be performed to obtain information on the variability of aerosol-cloud interactions in the region. Finally, controlled lab studies will measure the IN properties of mineral dust and terrestrial and marine-derived bioparticles. A primary goal of ICE-T is to show that under given conditions, direct ice nucleation measurement(s), along with measurements of individual particle chemistry and size, can be used to predict the number of ice particles formed by nucleation mechanisms in select clouds. The ground, aircraft, and lab studies aim to better understand the impacts of different sources on cloud properties and precipitation in the Caribbean region, including long range transported African Dust, biological particles, marine sea spray, and pollution.In-situ measurements of the composition and sources of IN coupled with other measurements of microphysics, meteorology, and thermodynamics will provide unprecedented insight into the cloud impacts from different sources of particles, with a particular focus on the role of dust and bioparticles in ice nucleation processes in warm (-15 degrees C) maritime clouds in a tropical region. The results will lead to a better understanding of how mineralogy and aging of dust from the largest source region in the world impacts clouds and precipitation in the Caribbean region, a highly under-studied region with sensitive ecosystems. Results from the studies will be used to constrain and improve models to better predict ice cloud formation on a global scale. Students will be trained across disciplines of chemistry, physics, modeling, atmospheric chemistry, and instrument development. These students will have the opportunity to interact with a broad range of scientists and students from multiple schools and organizations as part of ICE-T, as well as in the Puerto Rico and Virgin Island area. A web page focusing on these studies will be developed as well as a public exhibit at the Birch Aquarium focusing on ice clouds and how they form in the atmosphere and impact climate and weather. A mobile exhibit will be taken to local elementary schools to teach children about clouds and climate. University of Puerto Rico students will assist with measurements during the campaign as well as with subsequent analysis and integration of the results. Project results will be used to educate the public on how the aerosols chemistry can impact regional and global precipitation patterns and climate.