Modeling Cloud Responses to Global Atmospheric Circuit Variability

模拟云对全球大气回路变化的响应

• 批准号: 0855351
• 负责人: Brian Tinsley
• 金额: $ 30.51万
• 依托单位: University of Texas at Dallas
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-12-01 至 2014-11-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0855351&HistoricalAwards=false
• 关键词: Modeling; Cloud; Responses; Global; Atmospheric

Prior work has shown consistent correlations between changes in atmospheric circulation and current flow in the global atmospheric electric circuit. The current in this circuit is modulated by external factors, such as variations in the solar wind, and internal factors, such as the variation of ionospheric electrical potential due to variation in occurrence of thunderstorms and other highly electrified cloud generators. The nature of these correlations eliminates several proposed sun- earth weather links, and requires a mechanism that also explains atmospheric responses to global circuit changes due to internal processes. The proposed mechanism is that changes in cloud processes are produced by the effect of varying electrical charge in the atmosphere on rates of aerosol scavenging processes in liquid water and ice clouds. Variations in this electrical space charge are associated with variations in the vertical current density of the global circuit.This project will extend previously published models describing this ion-cloud interaction. It will result in creation of a comprehensive data base of collision rate coefficients for scavenging of aerosol particles by cloud droplets and ice particles. The outcome will be improved parameterization of electrical effects on aerosol scavenging that will be suitable for introduction into a range of cloud and atmospheric circulation models. Once incorporated into these models, these parameterizations will improve quantitative treatment of electrical effects on precipitation, atmospheric radiation balance, and other aspects of atmospheric behavior in which clouds are involved. This project also will enhance an existing model of the global atmospheric electric circuit by better accounting for the resistive effects of clouds in the total ionosphere-earth column resistance. Better treatment of processes responsible for charging of layer clouds will be developed that include the effects of turbulence in distributing the charge within the cloud, and better describe of charge exchange between droplets, aerosol particles, and ions. The global variation of cloud responses to changes in cosmic ray flux will be evaluated using this global circuit model. Model results will be compared with available observations and laboratory work.The broader impact of the work includes improved understanding of the role of scavenging and processing of aerosol particles in clouds. Electrical effects on scavenging are not a part of present cloud models. Electrical processes are likely to be responsible for some of the present lack of agreement between models and observations, especially for primary ice nucleation in clouds. Better treatment of these processes will lead to improvements in forecasting weather, and to better understanding of weather and climate changes due to human aerosol production and due to changing solar activity inputs. The project includes the training of graduate students in computer modeling techniques. The subject of human and solar influences on climate is of wide community interest, and project scientists will continue educating University of Texas-Dallas students and faculty, the community, and the media on this topic.

先前的工作表明，大气环流的变化与全球大气电路中的电流流动之间存在一致的相关性。该电路中的电流受到外部因素（例如太阳风的变化）和内部因素（例如由于雷暴和其他高度带电的云发生器的发生变化而引起的电离层电势的变化）的调制。这些相关性的性质消除了几个建议的太阳-地球天气联系，并需要一个机制，也解释了大气响应全球电路变化，由于内部过程。提出的机制是云过程的变化是由大气中不同的电荷对液态水和冰云中气溶胶清除过程的影响产生的。这种空间电荷的变化与全球电路的垂直电流密度的变化有关。本项目将扩展以前发表的描述这种离子云相互作用的模型。这将导致建立一个全面的碰撞率系数数据库，用于云滴和冰粒清除气溶胶粒子。其结果将是改进的参数化的电效应对气溶胶清除，这将适合于引入到一系列的云和大气环流模型。一旦纳入这些模型，这些参数化将改善定量处理的电效应对降水，大气辐射平衡，以及其他方面的大气行为，其中云的参与。该项目还将通过更好地考虑云在总电离层-地球柱电阻中的电阻效应，增强现有的全球大气电路模型。更好地处理负责层云充电的过程将被开发，包括湍流在云内分布电荷的影响，并更好地描述液滴，气溶胶粒子和离子之间的电荷交换。云对宇宙线通量变化的响应的全球变化将使用这个全球电路模型进行评估。模型结果将与现有观测和实验室工作进行比较，其更广泛的影响包括提高对清除和处理云中气溶胶粒子的作用的认识。清除的电效应不是目前云模型的一部分。 电气过程可能是负责一些目前缺乏协议之间的模式和观测，特别是在云中的初级冰成核。更好地处理这些过程将导致天气预报的改进，并更好地了解由于人类气溶胶的产生和由于太阳活动输入的变化而引起的天气和气候变化。该项目包括对研究生进行计算机建模技术培训。人类和太阳对气候的影响这一主题引起了广泛的社区兴趣，项目科学家将继续教育德克萨斯大学达拉斯分校的学生和教师，社区和媒体。