The chemical composition of the atmosphere is determined by a combination of chemical reactions, radiation flux, and transport of species. Processes that occur in the gaseous phase in the stratosphere include thermal gas phase reactions and photochemical reactions. Heterogeneous reactions occur between gas phase molecules in/on aerosols and polar stratospheric clouds. Models that attempt to simulate the chemical composition of the stratosphere require a number of parameters that can be measured directly in the laboratory. In the gas phase, these include reaction rate constants, product branching ratios, and photolysis quantum yields. Gas phase reaction rate constants, if determined at stratospheric temperature and pressure, are used directly in models. Photochemical reactions or heterogeneous reactions the data measured in the laboratory require transformation prior to use in model calculations. For example, quantum yield calculations used in models need to account for solar flux. In the case of heterogeneous reactions, the nature, size and distribution of aerosol particles must be considered. Advances in experimental measurements and in the understanding of the measurements themselves, have improved atmospheric models.
KeywordsCombustion Methane Hydrolysis Microwave Sulfide
Unable to display preview. Download preview PDF.
- Brown AC, CE Canosa-Mas, AD Parr, RP Wayne (1990) Laboratory studies of some halogenated ethanes and ethers: measurements of rates of reaction with OH and of infrared absorption cross-sections. Atmos Environ 24A:2499–2511Google Scholar
- Burkholder JB, RK Talukdar, AR Ravishankara, S Solomon (1993). Temperature dependence of the HNO3 UV absorption cross sections. J Geophys Res 98:22937 – 22948Google Scholar
- DeMore WB, SP Sander, DM Golden, RF Hampson, M J Kurylo, CJ Howard, AR Ravishankara, CE Kolb, MJ Molina (1994) Chemical kinetics and photochemical data for use in stratospheric modeling. JPL Publication 94–26.Google Scholar
- Golden DM, LR Williams (1993) In: Low-temperature chemistry of the atmosphere. Moorgat GK, AJ Barnes, G Le Bras, JR Sodeau (eds) 235–262, Spring-Verlag New YorkGoogle Scholar
- Rossi M (1995) Compilation of kinetic data on heterogeneous reactions. J Phys Chem Ref Data, in press.Google Scholar
- Sander SP, RR Friedl (1989) Kinetics and product studies of the reaction ClO + BrO using flash photolysis-ultraviolet absorption. J Chem Phys 71:5183–5190Google Scholar