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月在加勒比地区进行的云中冰实验-热带地区运动（Ice - t）期间，在NSF/NCAR C-130研究飞机上部署机载气溶胶飞行时间质谱仪（A-ATOFMS）。现场大气冰核（In）测量将使用单粒子的质谱特征来确定这些云中冰核的来源。将供云的气溶胶组成与云凝结核（CCN）和云内的IN残留物的组成进行比较，以确定哪些颗粒源富集为IN。另外一个ATOFMS将在波多黎各的热带山地云雾林中进行连续气溶胶测量，作为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，以获得关于该地区气溶胶-云相互作用变异性的信息。最后，受控的实验室研究将测量矿物粉尘和陆源和海洋生物颗粒的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，以及单个颗粒化学和大小的测量，可以用来预测在选定的云中由成核机制形成的冰颗粒的数量。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，包括远距离运输的非洲沙尘、生物颗粒、海洋浪花和污染。IN的组成和来源的现场测量加上微物理学、气象学和热力学的其他测量，将为不同颗粒来源对云的影响提供前所未有的见解，特别关注热带地区温暖（-15摄氏度）海洋云中尘埃和生物颗粒在冰核过程中的作用。这些结果将使人们更好地了解来自世界上最大源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，加勒比地区是一个具有敏感生态系统的高度未被研究的地区。这些研究的结果将用于约束和改进模型，以更好地预测全球范围内冰云的形成。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科学家和学生以及波多黎各和维尔京岛地区的学生进行互动。将建立一个关于这些研究的网页，并在伯奇水族馆举办一个公众展览，重点关注冰云及其在大气中如何形成并影响气候和天气。一个移动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协助在活动期间进行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.