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

本研究计画包括实地调查雾滴族群间的化学异质性，以及这种异质性对气溶胶与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，旨在提供更好的分辨率的液滴组成作为液滴大小的函数。 这些采样器在过冷云中提供3级水滴收集，在暖云和雾中提供5级收集。 新的多级收集器将部署在两个主要领域的运动测量滴大小分辨雾的成分：在2000/01年冬季期间的加州区域PM10/PM2.5空气质量研究（CRPAQS）在圣华金河谷密集和在2001/02年冬季在丹佛的棕色云雾的气溶胶处理的研究。这两项研究的结果将代表一个相当大的进步，在理解如何雾滴组合物在整个下降的大小谱变化和这种变化对气溶胶的形成（通过气体吸收和含水硫氧化）和去除（通过下降沉积）的影响。 CRPAQS研究还将提供第一个很好的机会来测试尺寸分辨雾化学模型准确预测雾的尺寸依赖化学成分的能力。 还将开发一种新的两级不锈钢烟雾采样器，并在两个现场活动中部署。 该仪器将提供关于有机碳在液滴大小谱中的分布及其对城市雾通过清除和沉积清除大气中有机气溶胶颗粒的能力的影响的第一个可靠信息。

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.