Laboratory Studies of Vapor Grown Ice at Low and High Supersaturations

低过饱和度和高过饱和度下气相生长冰的实验室研究

• 批准号: 2128347
• 负责人: Jerry Harrington
• 金额: $ 91.6万
• 依托单位: Pennsylvania State Univ University Park
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2024-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2128347&HistoricalAwards=false
• 关键词: Laboratory; Studies; Vapor; Grown; Ice

Clouds that consist of ice crystals, such as cirrus, have a significant impact on weather and climate because of their role in interacting with incoming or outgoing radiation. However, there is still a significant amount of uncertainty about the processes that impact ice crystal growth from water vapor at very high altitudes and cold temperatures. This project will conduct laboratory-based measurements of ice crystal growth at temperatures of colder than -40 degrees to reduce uncertainties and provide information that can be used in weather and climate models. This award will also support multiple students and the creation of software for classroom use, thereby training the next generation of scientists.The research team will continue their studies of the growth of ice in laboratory chambers. The overarching goal of the work is to use measurements to estimate characteristic supersaturations and effective densities at low temperatures, and at low to high supersaturations. The resulting growth data will reduce uncertainties in calculating vapor growth rates at low temperatures and could be used to develop new parameterizations suitable for microphysical models. Specifically, the research plan is to: 1) Measure the dimensional growth rates of ice crystals grown from the tip of a single capillary at temperatures below -40°C and at a range of supersaturations using a diffusion chamber constructed for capillary studies. This would result in characteristic supersaturation and effective density measurements for faceted growth under -40°C.2) Explore high supersaturation growth through the use of a levitation diffusion chamber and capillary diffusion chamber. This would result in a measure of growth rates that result from branching and hollowing of ice as it forms.3) Measure the rate of facet development on the surface of frozen water droplets using a new growth chamber.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

由冰晶组成的云，如卷云，对天气和气候有重大影响，因为它们与入射或流出的辐射相互作用。然而，在非常高的海拔和寒冷的温度下，水蒸气对冰晶生长的影响过程仍然存在大量的不确定性。该项目将在零下40度以下的温度下进行基于实验室的冰晶生长测量，以减少不确定性，并提供可用于天气和气候模型的信息。该奖项还将支持多名学生和课堂使用软件的创建，从而培养下一代科学家。研究小组将继续研究实验室室内冰的生长情况。这项工作的总体目标是使用测量来估计低温和低到高过饱和度下的特征过饱和度和有效密度。由此产生的生长数据将减少计算低温下蒸汽生长速率的不确定性，并可用于开发适合微物理模型的新参数化。具体来说，研究计划是：1)使用为毛细管研究建造的扩散室，测量在低于-40°C的温度和过饱和范围内，从单个毛细管尖端生长的冰晶的尺寸增长率。这将导致在-40°c下的面生长的特征过饱和和有效密度测量。2)通过使用悬浮扩散室和毛细管扩散室来探索高过饱和生长。这样就可以测量出冰在形成过程中产生的分支和空穴所产生的生长速率。3)利用新的生长室测量冻结水滴表面小面发育速率。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Re-evaluating cloud chamber constraints on depositional ice growth in cirrus clouds – Part 1: Model description and sensitivity tests

• DOI: 10.5194/acp-23-6043-2023
• 发表时间: 2023-06
• 期刊: Atmospheric Chemistry and Physics
• 影响因子: 6.3
• 作者: K. Lamb;J. Harrington;B. Clouser;E. Moyer;L. Sarkozy;V. Ebert;O. Möhler;H. Saathoff

Effective Density Derived from Laboratory Measurements of the Vapor Growth Rates of Small Ice Crystals at −65° to −40°C

有效密度源自小冰晶在 65° 至 40°C 温度下的蒸汽生长速率的实验室测量

• DOI: 10.1175/jas-d-22-0077.1
• 发表时间: 2023
• 期刊: Journal of the Atmospheric Sciences
• 影响因子: 3.1
• 作者: Pokrifka, Gwenore F.;Moyle, Alfred M.;Harrington, Jerry Y.
• 通讯作者: Harrington, Jerry Y.