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Laboratory Studies of Heterogeneous Chemistry in the Upper Troposphere/Lower Stratosphere

对流层上层/平流层下层异质化学的实验室研究

基本信息

批准号：
9711969
负责人：
Margaret Tolbert
金额：
$ 41.71万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
1998
资助国家：
美国
起止时间：
1998-02-01 至 2002-01-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=9711969&HistoricalAwards=false
关键词：
Laboratory Studies Heterogeneous Chemistry Upper

项目摘要

9711969 Tolbert In this project, laboratory studies of particle formation and heterogeneous chemical reactions under conditions relevant for the upper troposphere/lower stratosphere will be performed. The composition, formation mechanism and abundance of polar stratospheric clouds (PSCs) remain uncertain, and the role of heterogeneous chemistry in the upper troposphere has not been established. To probe particle formation, several types of experiments will be performed. First FTIR reflection absorption spectroscopy (RAS) will be used to make fundamental measurements of homogeneous and heterogeneous nucleation parameters for atmospheric materials. Diffusion activation energies and contact parameters will be determined to provide the necessary input for nucleation theory. Other laboratory experiments will probe the formation mechanisms of PSCs, in particular, type Ia PSCs, whose exact composition is still unknown. In addition, laboratory studies of heterogeneous chemical reactions of potential importance in the upper troposphere will be performed. The most abundant types of particles there are thought to be cirrus, subvisible cirrus, and sulfate aerosols. A Knudsen cell flow reactor coupled with FTIR RAS to probe the condensed phase will be used. Oxidation/reduction reactions that may occur between oxygenated organics and nitric acid condensed on cirrus particles will be studied, and experiments on the reactivity of deliquesced and crystalline sulfate salts will be performed.

在这个项目中，将在对流层上层/平流层下层有关条件下进行粒子形成和非均相化学反应的实验室研究。极地平流层云（PSCs）的组成、形成机制和丰度仍不确定，非均质化学在对流层上层的作用尚未确定。为了探测粒子的形成，将进行几种类型的实验。首先，FTIR反射吸收光谱（RAS）将用于对大气材料的均匀和非均匀成核参数进行基本测量。将确定扩散活化能和接触参数，为成核理论提供必要的输入。其他实验室实验将探索PSCs的形成机制，特别是Ia型PSCs，其确切成分尚不清楚。此外，将对对流层上层可能具有重要意义的非均相化学反应进行实验室研究。最丰富的颗粒类型被认为是卷云、不可见卷云和硫酸盐气溶胶。将使用Knudsen细胞流动反应器与FTIR RAS相结合来探测凝聚相。将研究含氧有机物和凝结在卷云颗粒上的硝酸之间可能发生的氧化/还原反应，并进行潮解和结晶硫酸盐的反应性实验。