Current understanding of atmospheric processes in the troposphere and stratosphere, in particular stratospheric ozone-controlling photochemistry, allows evaluation of the effects on the stratosphere of chlorine-containing compounds envisioned as CFC (chlorofluorocarbon) replacements prior to their production and release. Such evaluations can help to direct decisions on selecting CFC alternatives and define acceptable levels of production or emission. We employ a two-dimensional (latitude and altitude) computational representation of the troposphere and stratosphere which incorporates physical processes, e.g., species transport and radiative transfer, and homogeneous photochemical processes. Laboratory measurements of OH and O(/sup 1/D) reactivity and spectral parameters of the alternative HCFC (hydrochlorofluorocarbon) compounds were used as input. The model-derived ozone depletion potential (ODP) is a defined quantity relating the effect on ozone of emission of a species to the model-calculated effect of a standard compound, here CFC-11 (CFCl/sub 3/). Globally and annually averaged ozone depletion potentials vary from less than .02 to greater than 1.0 for various CFCs and HCFCs, primarily as a result of differences in calculated atmospheric lifetimes. Differences in stratospheric photochemistry among CFCs and HCFCs play a smaller but significant role. Zonally averaged ODPs for some compounds can range over a factor of three with latitude, however, as a result of differences in stratospheric lifetime and the altitude profile of Cl release in CFC or HCFC loss processes. While globally defined ODPs are useful in designing methods to reduce the overall stratospheric Cl burden and its impact on ozone, latitudinally and seasonally varying ODPs must be additionally considered as knowledge of specific areas of the impacts of decreasing ozone column abundance increases. 6 refs., 4 figs., 4 tabs.
Connell, P. S. and Wuebbles, D. J.. "Evaluating CFC (chlorofluorocarbon) alternatives from the atmospheric viewpoint: Revision 1." , May. 1989.Connell, P. S., & Wuebbles, D. J. (1989). Evaluating CFC (chlorofluorocarbon) alternatives from the atmospheric viewpoint: Revision 1.Connell, P. S., and Wuebbles, D. J., "Evaluating CFC (chlorofluorocarbon) alternatives from the atmospheric viewpoint: Revision 1," (1989)@conference{osti_6079980, author = {Connell, P. S. and Wuebbles, D. J.}, title = {Evaluating CFC (chlorofluorocarbon) alternatives from the atmospheric viewpoint: Revision 1}, annote = {Current understanding of atmospheric processes in the troposphere and stratosphere, in particular stratospheric ozone-controlling photochemistry, allows evaluation of the effects on the stratosphere of chlorine-containing compounds envisioned as CFC (chlorofluorocarbon) replacements prior to their production and release. Such evaluations can help to direct decisions on selecting CFC alternatives and define acceptable levels of production or emission. We employ a two-dimensional (latitude and altitude) computational representation of the troposphere and stratosphere which incorporates physical processes, e.g., species transport and radiative transfer, and homogeneous photochemical processes. Laboratory measurements of OH and O(/sup 1/D) reactivity and spectral parameters of the alternative HCFC (hydrochlorofluorocarbon) compounds were used as input. The model-derived ozone depletion potential (ODP) is a defined quantity relating the effect on ozone of emission of a species to the model-calculated effect of a standard compound, here CFC-11 (CFCl/sub 3/). Globally and annually averaged ozone depletion potentials vary from less than .02 to greater than 1.0 for various CFCs and HCFCs, primarily as a result of differences in calculated atmospheric lifetimes. Differences in stratospheric photochemistry among CFCs and HCFCs play a smaller but significant role. Zonally averaged ODPs for some compounds can range over a factor of three with latitude, however, as a result of differences in stratospheric lifetime and the altitude profile of Cl release in CFC or HCFC loss processes. While globally defined ODPs are useful in designing methods to reduce the overall stratospheric Cl burden and its impact on ozone, latitudinally and seasonally varying ODPs must be additionally considered as knowledge of specific areas of the impacts of decreasing ozone column abundance increases. 6 refs., 4 figs., 4 tabs.}, url = {https://www.osti.gov/biblio/6079980}, place = {United States}, organization = {Lawrence Livermore National Lab., CA (USA)}, year = {1989}, month = {05}}You mustSign In orCreate an Account in order to save documents to your library.