Diagnostic and Process-Oriented Modeling Studies of the Tropospheric Cycles of S, N and Ozone

9617378 Chamedes该项目由两个独立但相关的调查组成，重点是大气氧化能力的变化和化学引起的气候变化。第一项研究活动将是对南半球海洋气溶胶特性实验(ACE-1)期间南大洋上空16次飞行收集的数据集进行诊断性分析和建模。这项实验是为了更好地了解控制大气气溶胶形成和气候变化特性的化学和物理过程。计划利用ACE-1数据集的这一部分进行的具体调查包括：(1)测试HxOy光化学理论；(2)评估对流层臭氧的光化学；(3)估计氨氧化及其作为氮氧化物来源的作用；(4)研究气相硫的化学和形态及其气体向颗粒的转化。这项研究的另一个好处是开发了ACE-1相关航空测量数据和建模产品的合并数据集，将向国际科学界提供。第二项主要调查将是一项面向过程的模拟研究，旨在评估大陆边界层内潮解矿物气溶胶的气相和水相耦合化学。具体地说，这些颗粒物中的水相氧化作为大气二氧化硫的汇和颗粒硫酸盐的来源的可行性将被调查。最初，将根据美国南部和中国北部的数据，对地壳来源的内部混合粗大气溶胶进行概括性描述。这些描述将被用来描述矿物气溶胶在高相对湿度下的潮解特性。现有的多相大气光化学模型将用于阐明这些体系的气相和水相耦合化学。这项研究的结果将用于利用太平洋西北实验室开发的三维化学输送模型，在全球范围内评估矿物气溶胶在大气硫收支中的作用。

9617378 Chameides This project consists of two separate but related investigations which focus on changes in the oxidative capacity of the atmosphere and to chemically-induced climate change. The first research activity will be the diagnostic analysis and modeling of datasets collected in sixteen flights over the Southern Ocean during the Southern Hemisphere Marine Aerosol Characterization Experiment (ACE-1). This experiment was carried out to better understand the chemical and physical processes that control the formation and climate-changing properties of atmospheric aerosols. Specific investigations planned using this portion of the ACE-1 dataset include: (i) testing of HxOy photochemical theory, (ii) assessment of tropospheric ozone photochemistry, (iii) estimates of ammonia oxidation and its role as a source of NOx, and (iv) investigations of gas phase sulfur chemistry and speciation and its gas-to-particle conversion. An added benefit of this study will be the development of a merged dataset of the relevant airborne measurements from ACE-1 as well as the modeling products, which will be made available to the international scientific community. The second major investigation will be a process-oriented modeling study designed to assess the coupled gas- and aqueous-phase chemistry of deliquescent mineral aerosols within the continental boundary layer. Specifically, the viability of aqueous phase oxidation within these particles as a sink of atmospheric sulfur dioxide and a source of particulate sulfate will be investigated. Initially, a generalized description for an internally-mixed coarse aerosol of crustal origin, based on data from the southern United States and from northern China, will be adopted. These descriptions will then be used to characterize the deliquescent characteristics of mineral aerosols at high relative humidity. An existing multi-phase atmospheric photochemical model will be used to elucidate the coupled gas- and aqueous-phase chemistry of these systems. Results from this study will be used to assess the role of mineral aerosols in the atmospheric sulfur budget within a global context using a 3-dimensional Chemical Transport Model developed at the Pacific Northwest Laboratory.