• America Geophysical Union Annual Meeting Sessions

    2009:  Global methane cycle and its impacts on climate system and atmospheric chemistry

    Convener:

    Chris Butenhoff
    Portland State University
    USA
    cbuten@pdx.edu

    Qianlai Zhuang
    Purdue University
    USA
    qzhuang@purdue.edu

    Current atmospheric methane contributes ~20% of the anthropogenic forcing from long-lived greenhouse gases and plays an important role in atmospheric chemical dynamics. Methane's future impacts are highly uncertain, in part due to uncertainty in its sources (e.g., emissions from permafrost thawing), but more importantly due to incomplete understanding of the response of methane cycling to climate change. Here we solicit papers that (1) improve our understanding of the methane cycle, (2) study feedbacks between atmospheric methane and the global climate system as well as atmospheric chemistry and (3) report in situ measurements of methane fluxes and concentrations, satellite retrievals of atmospheric concentrations, or biogeochemistry and atmospheric modeling results. We especially encourage submissions that reduce source uncertainties, assess climate feedbacks, and estimate regional-scale emissions. This session grew out of a series of meetings sponsored by the National Center for Ecological Analysis and Synthesis.

     

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    2008:  Methane: Toward Accurate Estimates of Fluxes Over Regional Scales

    Convener:

    Chris Butenhoff
    Portland State University
    USA
    cbuten@pdx.edu

    Ed Dlugokencky
    NOAA ESRL
    USA
    ed.dlugokencky@noaa.gov

    Qianlai Zhuang
    Purdue University
    USA
    qzhuang@purdue.edu

    Xiaozhen Xiong
    NOAA NESDIS
    USA
    Xiaozhen.Xiong@noaa.gov

    Methane has a global warming potential of 72 over a 20 year time horizon; it, therefore, is a promising greenhouse gas to target for short-term relief in the growth of radiative forcing. Our understanding of the global methane budget is probably sufficient to develop reasonable emission mitigation strategies, but our ability to estimate fluxes over regional scales is not sufficient to verify emission reductions reported under climate treaties or emissions trading schemes. Better estimates of fluxes will require a better understanding of the processes that emit methane, and a model system that integrates a variety of data streams, including atmospheric observations and process model outputs, to estimate fluxes at high spatial and temporal resolution.

    This session will build on previous sessions organized by the NCEAS-sponsored (National Center for Ecological Analysis and Synthesis) methane working group. We invite contributions on methane biogeochemical cycling covering all spatial scales that deal with in situ observations of CH4 abundance and isotopic composition, remotely-sensed observations of CH4 abundance and land cover, field studies that relate fluxes to climate and other ecological parameters, process models, emissions inventories, and inversion models. The major goals of this session are to promote a synthesis of approaches to estimating regional CH4 flux estimates and to assess the current potential of assimilation methods for reducing uncertainties in the global methane budget.

     

     2007: Methane: Recent Findings (and Surprises) at the Local and Regional Scale and Approaches to Reducing Uncertainty in the Global Budget

    Methane is a critical contributing component to the atmosphere's radiation balance and oxidation chemistry. Despite its significance many surprises remain to challenge our understanding. Recent observations have raised questions about methane's global source distribution (satellite observations of the size and timing of tropical sources), magnitude and mechanisms of evasion (lakes and reservoirs) and even the potential of novel sources (upland plants) to affect the global budget. This session will gather experts taking a broad range of approaches to: 1) communicate current information on the mechanisms of methane emission from reservoirs, lakes and vegetation; 2) communicate the current state of the assessment of the accuracy and the uncertainty of in situ and satellite observations of methane abundance and land cover, field experiments of methane emissions, and modeling at various spatial scales; and 3) promote synthesis and cooperative mechanistic approaches in reducing uncertainties and expanding our quantitative understanding of methane emissions from the earth's surface.

    Convener:

    John Melack
    University of California, Santa Barbara
    USA
    melack@lifesci.ucsb.edu

    Patrick Crill
    Stockholm University
    Sweden
    patrick.crill@geo.su.se

     

      2006: Methane: Toward a Multiscale approach to Reducing Uncertainties in its Emissions

       

    Convener:

    Qianlai Zhuang
    Purdue University
    USA
    qzhuang@purdue.edu

    Ed Dlugokencky
    NOAA ESRL
    USA
    ed.dlugokencky@noaa.gov

    Merritt R. Turetsky,
    Michigan State University
    USA
    mrt@msu.edu

    Patrick Crill
    Stockholm University
    Sweden
    patrick.crill@geo.su.se
     
    Methane is a component in the global carbon cycle. It plays important roles in the global climate system and in determining background air quality. Despite its significance, large uncertainties still exist in methane's global budget, particularly for sources that vary over small spatial and temporal scales, such as wetlands. There are ongoing bottom-up approaches to reduce these uncertainties at the process level that meld measurements of fluxes and ecosystem parameters with process-based models and there are top-down approaches using space-based and in situ measurements of the spatial distribution of methane combined with atmospheric transport models. This session will gather experts taking both approaches to: 1) communicate current information on the mechanisms of methane emission from wetlands, rice paddies and other sectors (such as vegetation, landfills, industrial emissions, and oceanic emissions); 2) communicate the current state of in situ and satellite observations of methane abundance and land cover, field experiments of methane emissions, and modeling at various spatial scales; and 3) promote synthesis and coordination between bottom-up and top-down approaches in reducing uncertainties and expanding our quantitative understanding of methane emissions from the earth's surface.

       

    Special Section:  Synthesis of Recent Terrestrial Methane Emission Studies

    Zhuang, Q., and W. S. Reeburgh (2008), Introduction to special section on Synthesis of Recent Terrestrial Methane Emission Studies, J. Geophys. Res., 113, G00A02, doi:10.1029/2008JG000749

    Gauci, V., N. B. Dise, G. Howell, and M. E. Jenkins (2008), Suppression of rice methane emission by sulfate deposition in simulated acid rain, J. Geophys. Res., 113, G00A07, doi:10.1029/2007JG000501

    Gauci, V., S. Blake, D. S. Stevenson, and E. J. Highwood (2008), Halving of the northern wetland CH4 source by a large Icelandic volcanic eruption, J. Geophys. Res., 113, G00A11, doi:10.1029/2007JG000499

    Khalil, M. A. K., and C. L. Butenhoff (2008), Spatial variability of methane emissions from rice fields and implications for experimental design, J. Geophys. Res., 113, G00A09, doi:10.1029/2007JG000517

    Khalil, M. A. K., M. J. Shearer, R. A. Rasmussen, C. Duan, and L. Ren (2008), Production, oxidation, and emissions of methane from rice fields in China, J. Geophys. Res., 113, G00A04, doi:10.1029/2007JG000461

    Khalil, M. A. K., M. J. Shearer, R. A. Rasmussen, L. Xu, and J. Liu (2008), Methane and nitrous oxide emissions from subtropical rice agriculture in China, J. Geophys. Res., 113, G00A05, doi:10.1029/2007JG000462

    Sachs, T., C. Wille, J. Boike, and L. Kutzbach (2008), Environmental controls on ecosystem-scale CH4 emission from polygonal tundra in the Lena River Delta, Siberia, J. Geophys. Res., 113, G00A03, doi:10.1029/2007JG000505

    Turetsky, M. R., C. C. Treat, M. P. Waldrop, J. M. Waddington, J. W. Harden, and A. D. McGuire (2008), Short-term response of methane fluxes and methanogen activity to water table and soil warming manipulations in an Alaskan peatland, J. Geophys. Res., 113, G00A10, doi:10.1029/2007JG000496

    Walter, K. M., J. P. Chanton, F. S. Chapin, E. A. G. Schuur, and S. A. Zimov (2008), Methane production and bubble emissions from arctic lakes: Isotopic implications for source pathways and ages, J. Geophys. Res., 113, G00A08, doi:10.1029/2007JG000569

    White, J. R., R. D. Shannon, J. F. Weltzin, J. Pastor, and S. D. Bridgham (2008), Effects of soil warming and drying on methane cycling in a northern peatland mesocosm study, J. Geophys. Res., 113, G00A06, doi:10.1029/2007JG000609

    Xiong, X., C. Barnet, E. Maddy, C. Sweeney, X. Liu, L. Zhou, and M. Goldberg (2008), Characterization and validation of methane products from the Atmospheric Infrared Sounder (AIRS), J. Geophys. Res., 113, G00A01, doi:10.1029/2007JG000500

     

    Other Publications

       

    Zhuang, Q., J. M. Melack, S. Zimov, K. M. Walter, C. L. Butenhoff, and M. A. K. Khalil, Global methane emissions from wetlands, rice paddies, and lakes, Eos, 90(5), 37-38, 2009.

    Melillo, J.M., S. Hassol, D. Archer, T. Callaghan, F.S. Chapin III, T. Christensen, A.D. McGuire, K. Walter, and Q. Zhuang Methane from the Arctic: Global warming wildcard. Chapter in United Nations Environmental Programme Yearbook, 2008

       Methane database archived at NCEAS: