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| Titel |
Spatial and temporal patterns of CH4 and N2O fluxes in terrestrial ecosystems of North America during 1979–2008: application of a global biogeochemistry model |
| VerfasserIn |
H. Tian, X. Xu, M. Liu, W. Ren, C. Zhang, G. Chen, C. Lu |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 7, no. 9 ; Nr. 7, no. 9 (2010-09-10), S.2673-2694 |
| Datensatznummer |
250004965
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| Publikation (Nr.) |
 copernicus.org/bg-7-2673-2010.pdf |
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| Zusammenfassung |
| Continental-scale estimations of terrestrial methane (CH4) and nitrous
oxide (N2O) fluxes over a long time period are crucial to accurately
assess the global balance of greenhouse gases and enhance our understanding
and prediction of global climate change and terrestrial ecosystem feedbacks.
Using a process-based global biogeochemical model, the Dynamic Land
Ecosystem Model (DLEM), we quantified simultaneously CH4 and N2O
fluxes in North America's terrestrial ecosystems from 1979 to 2008. During
the past 30 years, approximately 14.69 ± 1.64 T g C a−1
(1 T g = 1012 g) of CH4, and 1.94 ± 0.1 T g N a−1 of N2O
were released from terrestrial ecosystems in North America. At the country
level, both the US and Canada acted as CH4 sources to the
atmosphere, but Mexico mainly oxidized and consumed CH4 from the
atmosphere. Wetlands in North America contributed predominantly to the
regional CH4 source, while all other ecosystems acted as sinks for
atmospheric CH4, of which forests accounted for 36.8%. Regarding
N2O emission in North America, the US, Canada, and Mexico
contributed 56.19%, 18.23%, and 25.58%, respectively, to the
continental source over the past 30 years. Forests and croplands were the
two ecosystems that contributed most to continental N2O emission. The
inter-annual variations of CH4 and N2O fluxes in North America
were mainly attributed to year-to-year climatic variability. While only
annual precipitation was found to have a significant effect on annual
CH4 flux, both mean annual temperature and annual precipitation were
significantly correlated to annual N2O flux. The regional estimates and
spatiotemporal patterns of terrestrial ecosystem CH4 and N2O
fluxes in North America generated in this study provide useful information
for global change research and policy making. |
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