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Seasonal Variability of Tropical Wetland CH4 emissions: the role of the methanogen-available carbon pool.
- Source :
- Biogeosciences Discussions; 2012, Vol. 9 Issue 1, p387-409, 23p
- Publication Year :
- 2012
-
Abstract
- We develop a dynamic methanogen-available carbon model (DMCM) to quantify the role of the methanogen-available carbon pool in determining the spatial and temporal variability of tropical wetland CH<subscript>4</subscript> emissions over seasonal timescales. We fit DMCM parameters to satellite observations of CH<subscript>4</subscript> columns from SCIAMACHY CH<subscript>4</subscript> and equivalent water height (EWH) from GRACE. Over the Amazon river basin we find substantial seasonal variability of this carbon pool (coefficient of variation=28±22 %) and a rapid decay constant (φ= 0.017 day<superscript>-1</superscript>), in agreement with available laboratory measurements, suggesting that plant litter is likely the prominent methanogen car bon source over this region. Using the DMCM we derive global CH<subscript>4</subscript> emissions for 2003-2009, and determine the resulting seasonal variability of atmospheric CH<subscript>4</subscript> on a global scale using the GEOS-Chem atmospheric chemistry and transport model. First, we estimate tropical emissions amount to 111.1 TgCH<subscript>4</subscript> yr<superscript>-1</superscript> of which 24% is emitted from Amazon wetlands. We estimate that annual tropical wetland emissions have in creased by 3.4 TgCH<subscript>4</subscript> yr<superscript>-1</superscript> between 2003 and 2009. Second, we find that the model is able to reproduce the observed seasonal lag between CH<subscript>4</subscript> concentrations peaking 1-3 months before peak EWH values. We also find that our estimates of CH<subscript>4</subscript> emissions substantially improve the comparison between the model and observed CH<subscript>4</subscript> surface concentrations (r = 0.9). We anticipate that these new insights from the DMCM represent a fundamental step in parameterising tropical wetland CH<subscript>4</subscript> emissions and quantifying the seasonal variability and future trends of tropical CH<subscript>4</subscript> emissions. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 18106277
- Volume :
- 9
- Issue :
- 1
- Database :
- Complementary Index
- Journal :
- Biogeosciences Discussions
- Publication Type :
- Academic Journal
- Accession number :
- 71892529
- Full Text :
- https://doi.org/10.5194/bgd-9-387-2012