Aircraft and Surface Observation of Aerosol and Cloud Properties in the Houston Area

该项目的目标是收集和分析德克萨斯州休斯敦及其周围地区的气溶胶和云特性的空中和地面数据。其目的是了解云层是如何受到形成它们的空气中气溶胶的化学和物理特性的影响的。在地面现场和安装在夏延II飞机上的仪器将测量当地气溶胶的尺寸分布、尺寸分辨的吸湿增长和云激活效率。这架飞机还配备了测量云滴尺寸分布的设备。这项工作的动机是观察到休斯顿和其他主要城市附近出现了降雨和闪电异常。对于这些异常现象，人们提出了几种解释，其中之一就是污染气溶胶对云微结构的可能影响。大城市是大量气溶胶的来源。尽管毫无疑问，与远离城市影响的地区相比，气溶胶负荷的增加会导致云滴的浓度更高，但目前还不清楚液滴浓度的增加对云的寿命、降水产生或云带电有什么影响。要回答这些问题，首先需要了解该项目将产生的气溶胶的云形成特性的基本信息。数据收集将与2005-2006年夏季由德克萨斯州环境质量委员会赞助的研究休斯顿地区污染的实地项目协调进行。该计划(称为TECHAQS-II)将提供雷达数据和其他辅助观测，以帮助解释云层和气溶胶测量结果。该项目的一个更广泛的影响是，它将为了解人为排放对云行为的影响做出贡献，这最终将有助于量化城市气溶胶对天气和气候的影响。该项目支持一名研究生，并为柯林斯博士暑期实地课程的本科生提供培训机会。

The objective of this project is to collect and analyze airborne and surface data on aerosol and cloud properties in and around Houston, Texas. The goal is to understand how clouds are influenced by the chemical and physical characteristics of the aerosols in the air in which they form. Instruments at a surface site and mounted in a Cheyenne II aircraft will measure size distributions, size-resolved hygroscopic growth, and cloud activation efficiency of the local aerosol. The airplane is also equipped to measure cloud droplet size distributions. The work is motivated by observations that have indicated rainfall and lightning anomalies in the vicinity of Houston and other major cities. Several explanations have been proposed to account for the anomalies, one of which is possible effects of pollution aerosols on cloud microstructure. Large cities are the source of abundant aerosols. Although there is no doubt that increased aerosol loading leads to higher concentrations of cloud droplets than in regions away from the urban influence, it is not clear what effect the increase in droplet concentration has on cloud lifetime, precipitation production, or cloud electrification. To answer these questions requires, as a start, the fundamental information on cloud-forming properties of aerosols that this project will produce. The data collection will be coordinated with a field program in the summers of 2005-06 to study pollution in the Houston area sponsored by the Texas Commission on Environmental Quality. That program (called TexAQS-II) will furnish radar data and other supporting observations to aid in interpreting the cloud and aerosol measurements. A broader impact of the project is the contribution it will make to understanding the influence of anthropogenic emissions on cloud behavior, which ultimately will help quantify the effects of urban aerosol on weather and climate. The project supports a graduate student and provides training opportunities for undergraduates in Dr. Collins's summer field course.