Ice Nuclei and Ice Formation Processes in Tropical Cumulus Clouds

热带积云中的冰核和冰形成过程

• 批准号: 1036028
• 负责人: Paul DeMott
• 金额: $ 42.69万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-11-01 至 2013-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1036028&HistoricalAwards=false
• 关键词: Ice; Nuclei; Formation; Processes; Tropical

This award will provide researchers the opportunity to improve our understanding of the sources, physical and chemical nature, and number concentrations of atmospheric ice nuclei (IN). The measurements and modeling involved to be conducted are important in order to elucidate the roles of primary and secondary ice formation processes in determining microphysical composition and precipitation formation in cumulus clouds. The main aspect of this study is participation in the Ice in Clouds Experiment - Tropical Field Campaign (ICE-T). ICE-T is focused on improved understanding of the role of primary and secondary ice production in developing towering cumulus clouds through access to measurements to be collected during June-July 2011 by the NSF/NCAR C-130 aircraft. Research flights will be based out of St. Croix, in the U.S. Virgin Islands, with a target data collection region over the Western Tropical Atlantic and adjacent Caribbean Sea. Work supported under this award will provide IN measurements using the Colorado State University continuous flow diffusion chamber (CFDC) instrument, which is a annular flow diffusion chamber employing axial thermal gradients for real time ice nuclei measurements. The specific objectives are to perform airborne measurements aboard the C-130 to constrain the concentration of aerosols available to initiate ice by primary ice nucleation processes within the clouds being investigated, and to determine contributions of dust versus associated or unassociated biological aerosol toward ice formation at temperatures warmer than -20 degC. These investigators will then collaborate with other members of the ICE-T science team to analyze in-cloud ice formation processes a combination of via observational data and detailed numerical simulations. This support will also allow the investigative team to continue efforts to advance the technology for making atmospheric measurements of IN, including specialized implementations for ICE-T and participation in the proposed Instrument Development and Education in Airborne Sciences project.The intellectual merit of the award rests in expected improvements in understanding ice formation processes tropical cumuli, which are ubiquitous at near-equatorial latitudes, and in defining the role of different classes (inert vs. biological) of natural ice nuclei in triggering the initial formation of ice (and ultimately, precipitation) in such clouds.The broader impact of the research will include postdoctoral scientist training, collaborations with scientists in other institutions and disciplines, and enhancing U.S. research infrastructure. The obtained will be important for addressing such topics as aerosol-cloud-climate interactions and tropical storm formation. Additionally, a number of public outreach and educational activities are planned during the ICE-T field campaign.

该奖项将为研究人员提供机会，以增进我们对大气冰核（IN）的来源、物理和化学性质以及数量浓度的了解。 为了阐明初级和次级冰形成过程在确定积云中微物理成分和降水形成中的作用，要进行的测量和建模非常重要。 这项研究的主要方面是参与云中冰实验-热带野外活动（ICE-T）。 ICE-T 的重点是通过获取 NSF/NCAR C-130 飞机在 2011 年 6 月至 7 月期间收集的测量数据，更好地了解初级和次级冰生成在形成高耸积云中的作用。 研究航班将以美属维尔京群岛的圣克罗伊为基地，目标数据收集区域为西热带大西洋和邻近的加勒比海。 该奖项支持的工作将使用科罗拉多州立大学连续流扩散室 (CFDC) 仪器提供 IN 测量，该仪器是一个环形流扩散室，采用轴向热梯度进行实时冰核测量。 具体目标是在 C-130 上进行机载测量，以限制可通过所研究的云内初级冰核过程引发冰的气溶胶浓度，并确定灰尘与相关或不相关的生物气溶胶对冰形成的贡献。温度高于-20 ℃。 然后，这些研究人员将与 ICE-T 科学团队的其他成员合作，结合观测数据和详细的数值模拟来分析云中冰的形成过程。 这种支持还将使研究团队能够继续努力推进 IN 大气测量技术，包括 ICE-T 的专门实施以及参与拟议的机载科学仪器开发和教育项目。该奖项的智力价值在于预计将改进对热带积云（在近赤道纬度地区普遍存在的冰形成过程）的理解，以及定义不同类别（惰性与生物）天然冰核在触发冰的初始形成中的作用（最终是降水）。这项研究的更广泛影响将包括博士后科学家培训、与其他机构和学科的科学家合作以及增强美国的研究基础设施。 所获得的结果对于解决气溶胶-云-气候相互作用和热带风暴形成等主题非常重要。 此外，ICE-T 实地活动期间还计划开展一些公共宣传和教育活动。