Aspects of CFC relative ozone destruction efficiencies determined in the LLNL 2-D model
We have investigated the efficiency of surface emission of several individual chlorofluorocarbons (CFCs) and hydrogen-containing chlorofluorocarbons (HCFCs) for reducing the calculated steady state total ozone column in both one- and two-dimensional models, relative to the effects of CFC-11 (CFCl/sub 3/) emission. We find that CFC and HCFC relative efficiencies can vary over two orders of magnitude, mostly as a result of atmospheric lifetimes. For CFCs and HCFCs with long stratospheric lifetimes the calculated efficiency is also reduced by the effects of lower and mid stratospheric photochemistry. Ozone in this region changes according to the net effect of changing rates of oxygen photolysis, direct chlorine-catalyzed ozone loss and interference by active chlorine species in the nitrogen oxide-catalyzed ozone loss process. In these cases, the relative efficiencies show a marked latitudinal dependence, being larger at high latitudes and smaller at lower latitudes. Additionally in these cases, the one-dimensional model appears to overestimate the globally and annually averaged result that is obtained from the two-dimensional model. These considerations should be taken into account when quantities similar to the relative efficiency defined here are applied to CFC production and emission decisions. 6 refs., 4 figs., 1 tab.
- Research Organization:
- Lawrence Livermore National Lab., CA (USA)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 7080139
- Report Number(s):
- UCRL-97987; CONF-8808102-4; ON: DE88015431
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHEMICAL REACTION KINETICS
CHLORINATED ALIPHATIC HYDROCARBONS
EFFICIENCY
FORECASTING
GROUND RELEASE
HALOGENATED ALIPHATIC HYDROCARBONS
KINETICS
MANAGEMENT
MATHEMATICAL MODELS
MINIMIZATION
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OZONE
REACTION KINETICS
TWO-DIMENSIONAL CALCULATIONS
WASTE DISPOSAL
WASTE MANAGEMENT