Use of satellite data to constrain the model-calculated atmospheric liftime for N sub 2 O: Implications for other trace gases
- Atmospheric and Environmental Research, Inc., Cambridge, MA (USA)
The source gases, such as nitrous oxide (N{sub 2}O) and chloroflurocarbons (CFCs), are released into the atmosphere at the Earth's surface and are removed mainly by photolysis in the stratosphere. The liftime is determined by the local photochemical removal rate of the gas and the efficiency of transport that carries the gas from where it is emitted to the dominant photochemical removal region. The authors calculate that approximately 80% of N{sub 2}O is removed in the stratosphere between 30{degree}N and 30{degree}S. Using the data for N{sub 2}O obtained fron the stratospheric and mesospheric sounder (SAMS) instrument on the Nimbus 7 satellite to constrain the model-calculated distributions, they concluded that previous models may have underestimated the magnitude of vertical transport over the tropics and that the calculated lifetime for N{sub 2}O and CFC source gases could be 30% shorter than previously reported values.The calculated lifetime for N{sub 2}O of 110 years would imply a source strength of 13 {times} 10{sup 6} tons (N)/yr, compared to a source strength of 9.2 {times} 10{sup 6} tons (N)/yr for a lifetime of 160 years. A shorter lifetime for the CFCs (47 years for CFC-11 and 95 years for CFC-12) would imply a more rapid decrease in the atmospheric chlorine content once the CFC emissions are stopped, making it possible to reach the pre-ozone hole value of 2 ppbv as early as 2045. Accurate determination of the lifetime of CFC-11 is particularly important, since the lifetime is used in the definitions of the ozone depletion potentials (ODP), chlorine loading potentials (CLP), and greenhouse warming potentials (GWP) of the replacement chemicals for the CFCs. A shorter lifetime for CFC-11 would elevate the magnitudes of ODP, CLP, and GWP for these chemicals.
- OSTI ID:
- 5599688
- Journal Information:
- Journal of Geophysical Research; (United States), Vol. 96:D4; ISSN 0148-0227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NITROUS OXIDE
ATMOSPHERIC CHEMISTRY
ORGANIC CHLORINE COMPOUNDS
ORGANIC FLUORINE COMPOUNDS
ENVIRONMENTAL TRANSPORT
GENERAL CIRCULATION MODELS
GREENHOUSE EFFECT
HOLES
LIFETIME
MESOSPHERE
OZONE LAYER
PHOTOCHEMICAL REACTIONS
PHOTOLYSIS
POLLUTION SOURCES
REMOVAL
SATELLITES
STRATOSPHERE
TROPICAL REGIONS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
DECOMPOSITION
EARTH ATMOSPHERE
LAYERS
MASS TRANSFER
MATHEMATICAL MODELS
NITROGEN COMPOUNDS
NITROGEN OXIDES
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)