Modeling Cloud Responses to Global Atmospheric Circuit Variability

先前的工作已经表明大气环流的变化与全球大气电路中的电流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云发生器的发生变化而导致的电离层电势的变化）的调制。这些相关性的本质消除了一些拟议的太阳-地球天气联系，并且需要一种机制来解释大气对由于内部过程导致的全球循环变化的反应。所提出的机制是，云过程的变化是由于大气中电荷变化对液态水和冰云中气溶胶清除过程速率的影响而产生的。这种空间电荷的变化与全局电路的垂直电流密度的变化相关。该项目将扩展先前发布的描述这种离子云相互作用的模型。它将创建一个关于云滴和冰颗粒清除气溶胶颗粒的碰撞率系数的综合数据库。结果将改进气溶胶清除的电效应参数化，适合引入一系列云和大气环流模型。一旦纳入这些模型，这些参数化将改进对降水、大气辐射平衡以及涉及云的大气行为的其他方面的电效应的定量处理。该项目还将通过更好地考虑云在电离层-地球柱总电阻中的电阻效应来增强全球大气电路的现有模型。将开发对层云带电过程的更好处理，包括云内电荷分布的湍流效应，并更好地描述液滴、气溶胶颗粒和离子之间的电荷交换。将使用该全局电路模型来评估云对宇宙射线通量变化的响应的全局变化。模型结果将与现有的观测结果和实验室工作进行比较。这项工作的更广泛影响包括提高对云中气溶胶颗粒清除和处理作用的理解。电对清除的影响不是当前云模型的一部分。 电过程可能是目前模型与观测之间缺乏一致性的原因，特别是对于云中的初级冰核。更好地处理这些过程将改善天气预测，并更好地了解由于人类气溶胶产生和太阳活动输入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的培训。人类和太阳对气候的影响这一主题引起了社区的广泛关注，项目科学家将继续就这一主题对德克萨斯大学达拉斯分校的学生和教师、社区和媒体进行教育。

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.