Modeling the large-scale effects of surface moisture heterogeneity on wetland carbon fluxes in the West Siberian Lowland

We used a process-based model to examine the role of spatial heterogeneity of surface and sub-surface water on the carbon budget of the wetlands of the West Siberian Lowland over the period 1948–2010. We found that, while surface heterogeneity (fractional saturated area) had little overall effect on...

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Bibliographic Details
Published in:Biogeosciences
Main Authors: T. J. Bohn, E. Podest, R. Schroeder, N. Pinto, K. C. McDonald, M. Glagolev, I. Filippov, S. Maksyutov, M. Heimann, X. Chen, D. P. Lettenmaier
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2013
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Online Access:https://doi.org/10.5194/bg-10-6559-2013
https://doaj.org/article/0ba5358eee5144929ae4898cc9b7bf2f
Description
Summary:We used a process-based model to examine the role of spatial heterogeneity of surface and sub-surface water on the carbon budget of the wetlands of the West Siberian Lowland over the period 1948–2010. We found that, while surface heterogeneity (fractional saturated area) had little overall effect on estimates of the region's carbon fluxes, sub-surface heterogeneity (spatial variations in water table depth) played an important role in both the overall magnitude and spatial distribution of estimates of the region's carbon fluxes. In particular, to reproduce the spatial pattern of CH 4 emissions recorded by intensive in situ observations across the domain, in which very little CH 4 is emitted north of 60° N, it was necessary to (a) account for CH 4 emissions from unsaturated wetlands and (b) use spatially varying methane model parameters that reduced estimated CH 4 emissions in the northern (permafrost) half of the domain (and/or account for lower CH 4 emissions under inundated conditions). Our results suggest that previous estimates of the response of these wetlands to thawing permafrost may have overestimated future increases in methane emissions in the permafrost zone.