Effects of Aerosols on Microphysical Properties of Springtime Clouds Containing Ice

气溶胶对春季含冰云微物理性质的影响

• 批准号: 0612605
• 负责人: Cynthia Twohy
• 金额: --
• 依托单位: Oregon State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-09-15 至 2010-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0612605&HistoricalAwards=false
• 关键词: Effects; Aerosols; Microphysical; Properties; Springtime

Ice clouds are important in regulating climate, in producing precipitation, and in providing sites for chemical reactions. Ice nucleation occurs in the atmosphere in two primary ways: through homogeneous freezing of liquid solution droplets and through heterogeneous interaction on a particulate nucleus. Homogeneous ice nucleation can be predicted by theory, while heterogeneous ice nucleation is much more complex. There are several mechanisms by which a heterogeneous ice nucleus may initiate ice formation, including deposition, contact, immersion, and condensation. The types and numbers of particles that act as ice nuclei under various conditions in the atmosphere are very poorly characterized. Changes to particulate loadings by anthropogenic activity, whether direct emissions or through land-use and precipitation changes, are likely to influence characteristics of ice and mixed-phase clouds. However, these "aerosol indirect effects" on ice clouds cannot be accurately predicted until we understand the physics of ice formation. Prior measurements provide a beginning, but much more information is needed. Further comprehension of ice nucleation will require a combination of field experiments, laboratory studies, and modeling. The Principal Investigator will undertake an experimental approach involving direct impaction and evaporation of ice crystals to evaluate the properties of their non-volatile nuclei. This information will be integrated with that from a series of complimentary measurements by other investigators. The primary objective in this work is to better understand ice nucleation in relatively simple clouds in the Ice in Clouds--Layer (ICE-L) experiment. Problems associated with sampling ice from aircraft, and their potential influence on collected data, will be studied using modeling calculations and field measurements. This will add to the intellectual merit of the basic ice nucleation studies. There are several aspects of this work that are important to the broader community. First, there is the primary importance of understanding how aerosol production due to human activity (whether directly or indirectly through land-use changes) influences precipitation development and the radiative impact of clouds on the earth's climate. Second, there is the positive impact on human resources. A strong educational component is planned for the ICE-L experiment, with new technology allowing real-time data to be integrated into university meteorology classes. Additionally, an undergraduate student and graduate students will work with the PI and colleagues to analyze and interpret the data collected. Additionally, this project will yield improved understanding of ice sampling by aircraft and its implications for past and future measurements in numerous other experiments.

冰云在调节气候，产生降水以及为化学反应提供位置方面很重要。 冰核以两种主要方式发生在大气中：通过液体溶液液滴的均质冻结以及通过颗粒核上的异质相互作用。 可以通过理论预测均匀的冰核，而异质冰核的复杂性要复杂得多。 在几种机制中，异质冰核可以启动冰形成，包括沉积，接触，浸入和凝结。 在大气中各种条件下充当冰核的颗粒的类型和数量的特征非常低。 通过人为活性，无论是直接排放还是通过土地利用和降水变化来改变颗粒载荷的变化，都可能影响冰和混合相云的特征。 但是，在我们了解冰形成物理学之前，无法准确预测这些对冰云的“气雾间接影响”。事先测量提供了一个开始，但需要更多信息。 进一步理解冰核将需要结合现场实验，实验室研究和建模。 主要研究者将采用一种实验方法，涉及直接撞击和冰晶蒸发，以评估其非易失性核的性质。 此信息将与其他研究人员的一系列免费测量结果整合在一起。 这项工作的主要目的是更好地理解云层（ICE-L）实验中冰中相对简单的云中的冰核。 将使用建模计算和现场测量来研究与飞机中采样冰有关的问题及其对收集数据的潜在影响。 这将增加基本冰核研究的智力优点。这项工作对更广泛的社区很重要。 首先，了解由于人类活动引起的气溶胶产生（无论是直接或间接通过土地利用变化）如何影响降水的发展以及云对地球气候的辐射影响。 其次，对人力资源有积极影响。 ICE-L实验计划了强大的教育组成部分，新技术允许将实时数据集成到大学气象学课程中。 此外，本科生和研究生将与PI及其同事一起分析和解释收集的数据。 此外，该项目将在许多其他实验中对飞机对冰采样的了解及其对过去和将来的测量的影响。