Radiative forcing calculations for CH{sub 3}Cl

Technical Report · Wed Jun 01 04:00:00 EDT 1994

DOI:https://doi.org/10.2172/10182808· OSTI ID:10182808

Grossman, A S; Grant, K E; Wuebbles, D J

Methyl chloride, CH{sub 3}Cl, is the major natural source of chlorine to the stratosphere. The production of CH{sub 3}Cl is dominated by biological sources from the oceans and biomass burning. Production has a seasonal cycle which couples with the short lifetime of tropospheric CH{sub 3}Cl to produce nonuniform global mixing. As an absorber of infrared radiation, CH{sub 3}Cl is of interest for its potential affect on the tropospheric energy balance as well as for its chemical interactions. In this study, we estimate the radiative forcing and global warming potential (GWP) of CH{sub 3}Cl. Our calculations use an infrared radiative transfer model based on the correlated k-distribution algorithm for band absorption. Global and annual average vertical profiles of temperature and trace gas concentration were assumed. The effects of clouds are modeled using three layers of global and annual average cloud optical properties. A radiative forcing value of 0.0053 W/m{sup 2}ppbv was obtained for CH{sub 3}Cl and is approximately linear in the background abundance. This value is about 2 percent of the forcing of CFC-11 and about 300 times the forcing of CO{sub 2}, on a per molecule basis. The radiative forcing calculation for CH{sub 3}Cl is used to estimate the global warming potential (GWP) of CH{sub 3}Cl. The results give GWPs for CH{sub 3}Cl of the order of 25 at a time of 20 years(CO{sub 2} = 1). This result indicates that CH{sub 3}Cl has the potential to be a major greenhouse gas if significant human related emissions were introduced into the atmosphere.

• 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: 10182808
• Report Number(s): UCRL-ID--118065; ON: DE94019018
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
540120
99 GENERAL AND MISCELLANEOUS
990200
CHEMICALS MONITORING AND TRANSPORT
CLOUDS
ENERGY BALANCE
GREENHOUSE EFFECT
INFRARED RADIATION
MATHEMATICAL MODELS
MATHEMATICS AND COMPUTERS
METHYL CHLORIDE
OPTICAL PROPERTIES
RADIATION FLUX
TROPOSPHERE