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| Titel |
Multifactor controls on terrestrial N2O flux over North America from 1979 through 2010 |
| VerfasserIn |
X. F. Xu, H. Q. Tian, G. S. Chen, M. L. Liu, W. Ren, C. Q. Lu, C. Zhang |
| 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 ; 9, no. 4 ; Nr. 9, no. 4 (2012-04-12), S.1351-1366 |
| Datensatznummer |
250006947
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| Publikation (Nr.) |
 copernicus.org/bg-9-1351-2012.pdf |
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| Zusammenfassung |
| Nitrous oxide (N2O) is a potent greenhouse gas which also contributes
to the depletion of stratospheric ozone (O3). However, the magnitude
and underlying mechanisms for the spatiotemporal variations in the
terrestrial sources of N2O are still far from certain. Using a
process-based ecosystem model (DLEM – the Dynamic Land Ecosystem Model)
driven by multiple global change factors, including climate variability,
nitrogen (N) deposition, rising atmospheric carbon dioxide (CO2),
tropospheric O3 pollution, N fertilizer application, and land
conversion, this study examined the spatial and temporal variations in
terrestrial N2O flux over North America and further attributed these
variations to various driving factors. From 1979 to 2010, the North America
cumulatively emitted 53.9 ± 0.9 Tg N2O-N (1 Tg = 1012 g), of
which global change factors contributed 2.4 ± 0.9 Tg N2O-N, and
baseline emission contributed 51.5 ± 0.6 Tg N2O-N. Climate
variability, N deposition, O3 pollution, N fertilizer application, and
land conversion increased N2O emission while the elevated atmospheric
CO2 posed opposite effect at continental level; the interactive effect
among multiple factors enhanced N2O emission over the past 32 yr. N
input, including N fertilizer application in cropland and N deposition, and
multi-factor interaction dominated the increases in N2O emission at
continental level. At country level, N fertilizer application and
multi-factor interaction made large contribution to N2O emission
increase in the United States of America (USA). The climate variability
dominated the increase in N2O emission from Canada. N inputs and
multiple factors interaction made large contribution to the increases in
N2O emission from Mexico. Central and southeastern parts of the North
America – including central Canada, central USA, southeastern USA, and all
of Mexico – experienced increases in N2O emission from 1979 to 2010.
The fact that climate variability and multi-factor interaction largely
controlled the inter-annual variations in terrestrial N2O emission at
both continental and country levels indicate that projected changes in the
global climate system may substantially alter the regime of N2O
emission from terrestrial ecosystems during the 21st century. Our study
also showed that the interactive effect among global change factors may
significantly affect N2O flux, and more field experiments involving
multiple factors are urgently needed. |
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