Chemical Heterogeneity Among Fog Drop Populations and Its Influence on Aerosol Processing by Fogs

这项研究项目包括实地考察雾滴种群之间的化学非均质性，以及这种非均质性对气溶胶和微量气体处理的影响。该项目涉及两个新的云/雾采样器的首次部署，这些采样器旨在根据液滴大小提供更好的液滴组成分辨率。这些采样器在过冷云中提供3级液滴采集，在暖云和雾中提供5级液滴采集。新的多级收集器将在两个主要的野外活动中用于测量雾滴大小分辨的雾成分：在2000/01年冬季，在圣华金河谷的加利福尼亚地区PM10/PM2.5空气质量研究(CRPAQS)期间，以及在2001/02年冬季，在丹佛棕云的雾雾处理研究中。这两项研究的结果将代表着在理解雾滴组成如何在液滴尺寸谱上变化以及这种变化对气溶胶形成(通过气体吸收和硫磺的氧化)和去除(通过液滴沉积)的影响方面取得了相当大的进步。CRPAQS的研究还将提供第一个很好的机会来测试大小分辨雾化学模型准确预测雾的大小相关化学成分的能力。还将开发一种新的两级不锈钢雾气采样器，并在这两个实地活动中进行部署。该仪器将首次提供有关有机碳在滴谱上的分布及其对城市雾通过清除和沉积净化大气中有机气溶胶颗粒的能力的影响的可靠信息。

This research project consists of field stidues to examine the chemical heterogeneity among fog drop populations and the effects this heterogeneity exerts on aerosol and trace gas processing. The project involves the first deployments of two new cloud/fog samplers designed to provide better resolution of drop composition as a function of drop size. These samplers provide 3-stage droplet collection in supercooled clouds and 5-stage collection in warm clouds and fogs. The new multi-stage collectors will be deployed to measure drop size-resolved fog composition in two major field campaigns: in winter 2000/01 during the California Regional PM10/PM2.5 Air Quality Study (CRPAQS) intensive in the San Joaquin Valley and in winter 2001/02 in a study of aerosol processing by fogs in Denver's Brown Cloud. Results from both studies will represent a considerable advance in understanding of how fog drop composition varies across the drop size spectrum and the influence of this variation on aerosol formation (via gas uptake and aqueous sulfur oxidation) and removal (via drop deposition). The CRPAQS study will also provide the first good opportunity to test the ability of size-resolved fog chemistry models to accurately predict the size-dependent chemical composition of fogs. A new 2-stage stainless steel fog sampler will also be developed and deployed in both field campaigns. This instrument will provide the first reliable information about the distribution of organic carbon across the drop size spectrum and its influence on the ability of urban fogs to cleanse the atmosphere of organic aerosol particles by scavenging and deposition.