Methane Emissions From Western Siberian Wetlands: Heterogeneity and Sensitivity to Climate Change

HR: 11:50h
AN: GC22A-06 [Abstracts]
TI: Methane Emissions From Western Siberian Wetlands: Heterogeneity and Sensitivity to Climate Change
AU: * Bohn, T J
EM: tbohn@hydro.washington.edu
AF: Dept. of Civil & Environmental Engineering, University of Washington, 201 More Hall Box 352700, Seattle, WA 98195-2700, United States
AU: Lettenmaier, D P
EM: dennisl@u.washington.edu
AF: Dept. of Civil & Environmental Engineering, University of Washington, 201 More Hall Box 352700, Seattle, WA 98195-2700, United States
AU: Podest, E
EM: erika.podest@jpl.nasa.gov
AF: Earth Science Division, NASA/Jet Propulsion Laboratory, M/S 300-233 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: McDonald, K C
EM: kyle.c.mcdonald@jpl.nasa.gov
AF: Earth Science Division, NASA/Jet Propulsion Laboratory, M/S 300-233 4800 Oak Grove Drive, Pasadena, CA 91109, United States
AU: Sathulur, K
EM: ksathulu@purdue.edu
AF: Dept. of Agronomy, Purdue University, Lilly Hall of Life Sciences 915 W. State Street, West Lafayette, IN 47907-2054, United States
AU: Bowling, L C
EM: bowling@purdue.edu
AF: Dept. of Agronomy, Purdue University, Lilly Hall of Life Sciences 915 W. State Street, West Lafayette, IN 47907-2054, United States
AU: Friborg, T
EM: tfj@geogr.ku.dk
AF: Dept. of Geography and Geology, University of Copenhagen, Øster Voldgade 10, Copenhagen, DK-1350, Denmark
AB: Prediction of methane emissions from high-latitude wetlands is important given concerns about their sensitivity to a warming climate. As a basis for prediction of wetland methane emissions at regional scales, we have coupled the Variable Infiltration Capacity macroscale hydrological model (VIC) with the Biosphere-Energy-Transfer- Hydrology terrestrial ecosystem model (BETHY) and a wetland methane emissions model to make large-scale estimates of methane emissions as a function of soil temperature, water table depth, and net primary productivity (NPP), with a parameterization of the sub-grid heterogeneity of the water table depth based on topographic wetness index. Using landcover classifications derived from L-band satellite synthetic aperture radar imagery, we simulated methane emissions for the Chaya River basin in western Siberia, an area that includes the Bakchar Bog, for a retrospective baseline period of 1980-1999, and evaluated their sensitivity to increases in temperature of 0-5 °C and increases in precipitation of 0-15%. The interactions of temperature and precipitation, through their effects on the water table depth, play an important role in determining methane emissions from these wetlands. The balance between these effects varies spatially, and their net effect depends in part on sub- grid topographic heterogeneity. Higher temperatures alone increase methane production in saturated areas, but cause those saturated areas to shrink in extent, resulting in a net reduction in methane emissions. Higher precipitation alone raises water tables and expands the saturated area, resulting in a net increase in methane emissions. Combining a temperature increase of 3 °C and an increase of 10% in precipitation, to represent the climate conditions likely in western Siberia at the end of this century, results in roughly a doubling of annual methane emissions. This work was carried out at the University of Washington, at Purdue University, and at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 1615 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 4805, 4912)
DE: 1631 Land/atmosphere interactions (1218, 1843, 3322)
DE: 1843 Land/atmosphere interactions (1218, 1631, 3322)
DE: 1890 Wetlands (0497)
SC: Global Environmental Change [GC]
MN: 2007 Fall Meeting