Atmospheric lifetime experiment. 3. Lifetime methodology and application to three years of CFCl/sub 3/ data
Observations of the chlorofluorocarbon CFCl/sub 3/ obtained several times daily over the period July 1978 to June 1981 at Adrigole, Ireland (52/sup 0/, 10/sup 0/W); Ragged Point, Barbados (13/sup 0/N, 59/sup 0/W); Point Matatula, American Samoa (14/sup 0/S, 171/sup 0/W); and Cape Grim, Tasmania (41/sup 0/S, 145/sup 0/E) are reported. In addition, observations at Cape Meares, Oregon (45/sup 0/N, 124/sup 0/W) are given for the period January 1980 to June 1981. On January 1, 1980, the average mixing ratio of CFCl/sub 3/ in the lower troposphere is estimated to have been 168 pptv, and this is calculated to have been increasing 5.7% annually. An optimal estimation procedure for deriving the atmospheric lifetime of CFCl/sub 3/ by using a nine-box two-dimensional model of the atmospheric is described. In this procedure, model parameters are estimated based upon minimizing the differences between the temporal trends observed and those calculated in the two-dimensional model. Assuming that the only destruction of CFCl/sub 3/ occurs in the stratosphere, the lifetime, on January 1, 1980, estimated by the trend technique is 83/sup +73//sub -/27 years; the lifetime estimated from the global inventory of CFCl/sub 3/ is 70/sup +89//sub -/25 years. The maximum likelihood current lifetime estimate obtained by combining the estimates from both analysis techniques is 78 years.
- Research Organization:
- School of Geophysical Sciences, Georgia Institute of Technology
- OSTI ID:
- 6733343
- Journal Information:
- J. Geophys. Res.; (United States), Vol. 88:C13
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
HALOGENATED ALIPHATIC HYDROCARBONS
ATMOSPHERIC CHEMISTRY
TROPOSPHERE
CHEMICAL COMPOSITION
MATHEMATICAL MODELS
MIXING RATIO
QUANTITY RATIO
CHEMISTRY
EARTH ATMOSPHERE
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)