Chemical Heterogeneity Among Cloud Drop Populations and its Effects on Sulfur Oxidation

云滴群体的化学异质性及其对硫氧化的影响

• 批准号: 9509596
• 负责人: Jeffrey Collett
• 金额: $ 32.95万
• 依托单位: Colorado State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1995
• 资助国家: 美国
• 起止时间: 1995-09-01 至 1999-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9509596&HistoricalAwards=false
• 关键词: Chemical; Heterogeneity; Among; Cloud; Drop

9509596 Collett Cloud chemistry models utilizing explicit treatments of cloud microphysics predict that cloud drop composition varies with drop size. Recent experimental observations confirm that large and small cloud drops typically have quite different chemical compositions. Chemical heterogeneity among cloud drop populations can influence removal rates for individual solutes, and can also enhance rates of sulfur oxidation relative to rates predicted from average cloud water properties. Clouds are major contributors to global atmospheric sulfate production. Developing an accurate picture of the atmospheric production of sulfate therefore requires an accurate understanding of the rate of sulfate production in real, chemically heterogeneous clouds. The primary objective of this project is to characterize variations in cloud drop chemistry across the drop size spectrum and determine how much sulfate production in clouds is enhanced by chemical heterogeneity among cloud drop populations. Data will be collected through simultaneous measurements of the chemical composition of multiple drop size classes. Cloud water will be collected with two cloud collectors used in previous work (two-stage, and three-stage, respectively), as well as a new five-stage instrument to be constructed as part of this project. Major ions, pH, free and complexed sulfur (IV), oxidants, and catalysts will be measured and used to characterize sulfur oxidation rates as a function of drop size. Measurements of the size-dependent aerosol composition and of soluble trace gases also will be made to determine the influence of particle and gas scavenging on the drop size-dependence of the cloud water composition.

9509596 Collett 云化学模式利用显式处理云微物理预测，云滴组成随滴大小。最近的实验观测证实，大的和小的云滴通常具有完全不同的化学成分。云滴种群之间的化学异质性可以影响单个溶质的去除率，也可以提高硫氧化率相对于从平均云水特性预测的速率。云是全球大气硫酸盐产生的主要贡献者。因此，要准确了解大气中硫酸盐的生成，就需要准确了解真实的化学成分不均匀的云层中硫酸盐的生成速率。 该项目的主要目标是描述整个水滴尺寸谱中云滴化学的变化，并确定云滴种群之间的化学异质性增强了云中硫酸盐的产生。将通过同时测量多个液滴大小类别的化学成分来收集数据。云水将用以前工作中使用的两个云收集器（分别为两级和三级）收集，以及作为本项目一部分建造的一个新的五级仪器。将测量主要离子、pH值、游离和络合硫（IV）、氧化剂和催化剂，并将其用于表征作为液滴尺寸函数的硫氧化速率。 还将测量与尺寸有关的气溶胶成分和可溶性痕量气体，以确定颗粒和气体清除对云水成分的液滴尺寸依赖性的影响。