HR: 0800h
AN: A41C-0061    [Abstracts]
TI: Estimating the Importance of Geologic Sources of Methane
AU: * Bruhwiler, L M
EM: lori.bruhwiler@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, R/CG1 325 Broadway, Boulder, CO 80304 United States
AU: Dlugokencky, E
EM: ed.dlugokencky@noaa.gov
AF: NOAA Climate Monitoring and Diagnostics Laboratory, R/CG1 325 Broadway, Boulder, CO 80304 United States
AU: Judd, A
EM: alarainejudd@supanet.com
AF: School of Marine Science and Technology, Armstrong Building University of Newcastle Upon Tyne, Newcastle Upon Tyne, NE1 7RU United Kingdom
AB: The contribution of geologic sources to the annual global budget of atmospheric methane is thought to range anywhere from a few Tg (teragrams) of CH₄ to tens of Tg of CH₄. Indeed, this term is the most uncertain element of the CH₄ budget as we currently understand it, and is generally neglected in studies of the atmospheric methane budget. Geologic methane sources are likely to be highly variable with the potential for sporadic catastrophic releases related to the instability of some reservoirs. The processes understood to lead to methane release from geologic reservoirs include seeps of oil and gas, mud volcanoes and gas hydrates. Although rough estimates of methane emissions from geologic sources have revealed the potential magnitude of the emissions, inventories for use in atmospheric models have not generally been available. We have developed a detailed inventory of likely geologic sources of methane, and we present here a study using an atmospheric transport model and CH₄ flux estimates for non-geologic sources optimzed using observations. We consider the extent to which global ground-based and satellite observations are in agreement with spatial distribution of geologic methane emissions given the uncertainties in the non-geologic sources.
DE: 0322 Constituent sources and sinks
DE: 0416 Biogeophysics
DE: 0428 Carbon cycling (4806)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005