HR: 1340h
AN: B43B-0157    [Abstracts]
TI: Insight Into West Siberian Gas and Wetland Methane Emissions From $\delta$$^{13}$C Studies of Ambient Air
AU: * Lowry, D
EM: d.lowry@gl.rhul.ac.uk
AF: Dept of Geology, Royal Holloway, University of London, Egham Hill, Egham, TW20 0EX United Kingdom
AU: Fisher, R
EM: r.fisher@gl.rhul.ac.uk
AF: Dept of Geology, Royal Holloway, University of London, Egham Hill, Egham, TW20 0EX United Kingdom
AU: Levin, I
EM: Ingeborg.Levin@iup.uni-heidelberg.de
AF: Institut f\"{u}r Umweltphysik, Universit\"{a}t Heidelberg, Im Neuenheimer Feld 229, Heidelberg, 69120 Germany
AU: Privalov, S
EM: Reshal@peterlink.ru
AF: Russian Centre for Remote Sensing of Atmosphere, Voeikovo, Vsevologsky region, Leningradskaya obl, 188685 Russian Federation
AU: Nisbet, E
EM: e.nisbet@gl.rhul.ac.uk
AF: Dept of Geology, Royal Holloway, University of London, Egham Hill, Egham, TW20 0EX United Kingdom
AB: The Ob River region of West Siberia is home to some of the largest known gasfields and wetlands, and a source of around 2.5% of the total global methane emissions. It is also a major source region of CO$_{2}$ emissions. Carbon isotopes of ambient air and emission sources provide an important tool for understanding these poorly constrained sources. Tank samples of ambient air were collected overnight for $\delta$$^{13}$C analysis of methane during the summer (August-September) campaigns of 1999 and 2000, as part of INTAS-funded projects. The main sampling centres were Nadym and Urengoy, with samples collected above the known gas reserves, near pumping stations and by boat on the Nadym River, downstream toward Salekhard. CH$_{4}$ of up to 900 ppb above background was recorded and $\delta$$^{13}$C depletions of up to 3$\permil$ relative to background. West Siberian gas has measured $\delta$$^{13}$C values of -51.5 to -49.5$\permil$ based on well samples and supplies in St. Petersburg and Germany. Implications from aircraft flights (Sugawara et al. 1996) and measurements along the Trans-Siberian railroad (Bergamaschi et al., 1998) are that the wetland signature is around -67$\permil$. The ambient air samples give a range of calculated source inputs from -67.3 to -49.3$\permil$, the end members corresponding to sampling areas expected to contain only wetland or gas emissions and confirmed by back trajectory analysis for sampling times. Using the end members, the average excess methane from the wetland source was 62 ppb around Nadym and 61 ppb around Urengoy. The average excess from the gasfields was 30 ppb around Nadym but 82 ppb around Urengoy, reflecting the closer proximity to the gasfields. The maximum excess recorded from wetlands was 160 ppb and from gasfields was 710 ppb. Experiments during summer 2004 have focussed on bag sampling on the tower of a super deep well at Korotchaevo, SE of the Urengoy gas field. Samples collected at 20, 30 and 60m heights will be analysed for $\delta$$^{13}$C of both CH$_{4}$ and CO$_{2}$ and apportioned to gas and wetland sources. Bergamaschi P.et al. Isotope analysis based source identification for atmospheric CH$_{4}$ and CO sampled across Russia using the Trans-Siberian railroad. J. Geophys. Res., 103 (D), 8227-8235, 1998. Suguwara S. et al. Aircraft measurements of the stable carbon isotopic ratio of atmospheric methane over Siberia. Global Biogeochem. Cycles, 10, 223-231, 1996.
DE: 0315 Biosphere/atmosphere interactions
DE: 0322 Constituent sources and sinks
DE: 0365 Troposphere--composition and chemistry
DE: 0368 Troposphere--constituent transport and chemistry
DE: 0394 Instruments and techniques
SC: Biogeosciences [B]
MN: 2004 AGU Fall Meeting