The radiative impact of uncertainties in perfluoromethane absorption measurements.
Abstract
Perfluoromethane, CF_4, is one of the more potent greenhouse gases with an atmospheric lifetime of several thousand years, so even small emissions of this gas would add to the radiative forcing in the future. The absorption cross section spectrum of CF_4 from various studies, including the Hitran 2000 database, is examined and the spectra are found to vary by more than 40%. The absorption cross section spectra are used to calculate global mean, direct radiative forcings using a line by line model and a narrow band model. The spread in the radiative forcings is shown to be greater than 30%. The IPCC quote the radiative forcings of CF_4 using the spectroscopic data from Hitran 1996. However, due to the large variation in the spectroscopic data for CF_4, such estimates cannot be relied upon. In light of the importance of CF_4 and the inconsistency in the absorption cross section spectra, more measurements of the cross section are strongly recommended.
- Publication:
-
EGS - AGU - EUG Joint Assembly
- Pub Date:
- April 2003
- Bibcode:
- 2003EAEJA.....6538G