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| Titel |
Attribution of spatial and temporal variations in terrestrial methane flux over North America |
| VerfasserIn |
X. F. Xu, H. Q. Tian, C. Zhang, M. L. Liu, W. Ren, G. S. Chen, C. Q. Lu, L. Bruhwiler |
| 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. 11 ; Nr. 7, no. 11 (2010-11-12), S.3637-3655 |
| Datensatznummer |
250005061
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| Publikation (Nr.) |
 copernicus.org/bg-7-3637-2010.pdf |
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| Zusammenfassung |
| The attribution of spatial and temporal variations in terrestrial methane
(CH4) flux is essential for assessing and mitigating CH4 emission
from terrestrial ecosystems. In this study, we used a process-based model,
the Dynamic Land Ecosystem Model (DLEM), in conjunction with spatial data of
six major environmental factors to attribute the spatial and temporal
variations in the terrestrial methane (CH4) flux over North America
from 1979 to 2008 to six individual driving factors and their interaction.
Over the past three decades, our simulations indicate that global change
factors accumulatively contributed 23.51 ± 9.61 T g CH4-C
(1 Tg = 1012 g) emission over North America, among which ozone (O3)
pollution led to a reduced CH4 emission by 2.30 ± 0.49 T g CH4-C.
All other factors including climate variability, nitrogen (N)
deposition, elevated atmospheric carbon dioxide (CO2), N fertilizer
application, and land conversion enhanced terrestrial CH4 emissions by
19.80 ± 12.42 T g CH4-C, 0.09 ± 0.02 T g CH4-C, 6.80 ± 0.86 T g CH4-C,
0.01 ± 0.001 T g CH4-C, and 3.95 ± 0.38 T g CH4-C,
respectively, and interaction between/among these
global change factors led to a decline of CH4 emission by 4.84 ± 7.74 T g CH4-C.
Climate variability and O3 pollution suppressed,
while other factors stimulated CH4 emission over the USA; climate
variability significantly enhanced, while all the other factors exerted
minor effects, positive or negative, on CH4 emission in Canada; Mexico
functioned as a sink for atmospheric CH4 with a major contribution from
climate change. Climatic variability dominated the inter-annual variations
in terrestrial CH4 flux at both continental and country levels.
Precipitation played an important role in the climate-induced changes in
terrestrial CH4 flux at both continental and country-levels. The
relative importance of each environmental factor in determining the
magnitude of CH4 flux showed substantially spatial variation across
North America. This factorial attribution of CH4 flux in North America
might benefit policy makers who would like to curb climate warming by
reducing CH4 emission. |
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