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月在加勒比地区开展“云中冰实验-热带实地活动”期间，在国家科学基金会/国家大气研究中心C-130研究飞机上部署一台空中气溶胶飞行时间质谱仪。 将使用单粒子质谱特征进行大气冰核（IN）的原位测量，以确定这些云中冰核的来源。供给云的气溶胶的成分将与云凝结核（CCN）和云内IN残留物的成分进行比较，以确定哪些粒子源被富集为IN。 另一个ATOFMS将在波多黎各的热带山地云雾林进行连续的气溶胶测量，作为由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组成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颗粒的IN特性。 ICE-T的一个主要目标是表明，在给定条件下，直接冰成核测量，沿着单个颗粒化学和尺寸的测量，可以用来预测在选定的云中由成核机制形成的冰粒的数量。 地面、飞机和实验室研究的目的是更好地了解不同来源对加勒比地区云特性和降水的影响，包括远距离传输的非洲尘埃、生物颗粒、海洋浪花和污染。和热力学将提供前所未有的洞察云的影响，从不同来源的粒子，特别是在温暖的（-15摄氏度）海洋云在热带地区的冰成核过程中的灰尘和生物粒子的作用。 研究结果将有助于更好地了解来自世界上最大来源地区的矿物学和灰尘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欠研究的敏感生态系统地区。 研究结果将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。 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，作为ICE-T的一部分，以及在波多黎各和维尔京群岛地区。 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共展览，重点是冰云及其如何在大气中形成并影响气候和天气。 一个移动的展览将被带到当地的小学，教孩子们关于云和气候的知识。 波多黎各大学的学生将在运动期间协助测量以及随后的分析和结果整合。 项目结果将用于教育公众了解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.