Radiative forcing for changes in tropospheric O{sub 3}
We have evaluated the radiative forcing for assumed changes in tropospheric O{sub 3} in the 500-1650 cm{sup {minus}1} wavenumber range. The radiative forcing calculations were performed as a function of latitude as well as for a globally and seasonally averaged model atmosphere, both in a clear sky approximation and in a model containing a representative cloud distribution. The scenarios involved radiative forcing calculations for O{sub 3} at normal atmospheric abundance and at a tropospheric abundance depleted by 25 ppbv, at each altitude, for all northern hemisphere latitudes. Normal abundances of H{sub 2}O, CO{sub 2}, CH{sub 4}, and N{sub 2}O were included in the calculations. The IR radiative forcing was calculated using a correlated k-distribution radiative transfer model. The tropospheric radiative forcing values are compared to the IPCC formulae for ozone tropospheric forcing as well as other published values to determine the validity of the correlated k-distribution approach to the radiative forcing calculations. The results for the global average atmosphere show agreement with previous results to the order of 10 percent. We conclude that the O{sub 3} forcing is linear in the background abundance and that the radiative forcing for ozone for the globally averaged atmosphere and the latitude averaged radiative forcing in the clear sky approximation are in agreement to within 10 percent. For the case of an atmosphere in which the tropospheric ozone has been depleted by 25 ppbv at all altitudes in the northern hemisphere, the mid latitude zone contributes {approximately}50 percent of the forcing, tropic zone contributes {approximately}37 percent of the forcing and the polar zone contributes {approximately}13 percent of the total forcing.
- Research Organization:
- California Univ., Livermore, CA (United States). Lawrence Livermore National Lab.
- Sponsoring Organization:
- USDOE, Washington, DC (United States); Environmental Protection Agency, Washington, DC (United States)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 10182806
- Report Number(s):
- UCRL-ID-118063; ON: DE94019017; TRN: 94:008217
- Resource Relation:
- Other Information: PBD: Jun 1994
- Country of Publication:
- United States
- Language:
- English
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