HR: 0800h
AN: A41C-0057    [Abstracts]
TI: A New Time-Dependent Inventory of Methane Emissions From Global Wetlands Based on Remote Sensing and Biogeochemical Modeling
AU: * Kaplan, J O
EM: jed.kaplan@ips.unibe.ch
AF: Institute of Plant Sciences, University of Bern, Altenbergrain 21, Bern, 3013 Switzerland
AU: * Kaplan, J O
EM: jed.kaplan@ips.unibe.ch
AF: Climate Change Unit, Institute for Environment and Sustainability, European Commission Joint Research Centre, TP 280, Ispra, 21020 Italy
AU: Bergamaschi, P
EM: peter.bergamaschi@jrc.it
AF: Climate Change Unit, Institute for Environment and Sustainability, European Commission Joint Research Centre, TP 280, Ispra, 21020 Italy
AU: Dentener, F
EM: frank.dentener@jrc.it
AF: Climate Change Unit, Institute for Environment and Sustainability, European Commission Joint Research Centre, TP 280, Ispra, 21020 Italy
AB: The dynamics of natural methane sources contribute to both seasonal and interannual variability in atmospheric methane concentrations. Wetlands are the largest natural source of methane and among the most variable in space and time. We compiled a new map of global wetlands using passive and active remote sensing based land cover information, and used these data to drive the LPJ-TG vegetation model to simulate wetland hydrology, biogeochemical cycling, and methane emissions over the period 1991-2004. Surface flux fields of wetland methane emissions were then coupled to the TM5 transport-chemistry model to simulate methane concentrations at a suite of tropospheric measuring stations. The new wetland map highlights the importance of seasonal wetlands in tropical floodplains and rainforests, while reducing estimates of boreal wetland area compared to previous work, especially in Europe. Our analysis further indicates that the tropics are likely to be a larger source of natural methane emissions than previously thought, and that interannual variability in methane emissions are driven by tropical wetlands, with year-on-year differences of up to 10% in the global wetland source. The seasonal cycle in wetland methane emissions is driven by northern hemisphere high-latitude peatlands, which have an annual amplitude of ca. 5 Tg. Sensitivity studies and comparison with observation networks of atmospheric methane concentrations demonstrate that this new inventory is a significant improvement over previous estimates in reproducing observed seasonal and interannual variability at several in-situ and aircraft-based measuring stations. The inventory will be an important component for evaluation of new remote sensing-based products of atmospheric methane concentrations.
DE: 0315 Biosphere/atmosphere interactions (0426, 1610)
DE: 0322 Constituent sources and sinks
DE: 0414 Biogeochemical cycles, processes, and modeling (0412, 0793, 1615, 4805, 4912)
DE: 0490 Trace gases
DE: 1890 Wetlands (0497)
SC: Atmospheric Sciences [A]
MN: Fall Meeting 2005