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| Titel |
Spatial scale-dependent land–atmospheric methane exchanges in the northern high latitudes from 1993 to 2004 |
| VerfasserIn |
X. Zhu, Q. Zhuang, X. Lu, L. Song |
| 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 ; 11, no. 7 ; Nr. 11, no. 7 (2014-04-01), S.1693-1704 |
| Datensatznummer |
250117334
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| Publikation (Nr.) |
 copernicus.org/bg-11-1693-2014.pdf |
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| Zusammenfassung |
| Effects of various spatial scales of water table dynamics on
land–atmospheric methane (CH4) exchanges have not yet been assessed for
large regions. Here we used a coupled hydrology–biogeochemistry model to
quantify daily CH4 exchanges over the pan-Arctic from 1993 to 2004 at
two spatial scales of 100 km and 5 km. The effects of sub-grid spatial
variability of the water table depth (WTD) on CH4 emissions were
examined with a TOPMODEL-based parameterization scheme for the northern high
latitudes. We found that both WTD and CH4 emissions are better simulated
at a 5 km spatial resolution. By considering the spatial heterogeneity of
WTD, net regional CH4 emissions at a 5 km resolution are
38.1–55.4 Tg CH4 yr−1 from 1993 to 2004, which are on average
42% larger than those simulated at a 100 km resolution using a
grid-cell-mean WTD scheme. The difference in annual CH4 emissions is
attributed to the increased emitting area and enhanced flux density with
finer resolution for WTD. Further, the inclusion of sub-grid WTD spatial
heterogeneity also influences the inter-annual variability of CH4
emissions. Soil temperature plays an important role in the 100 km estimates,
while the 5 km estimates are mainly influenced by WTD. This study suggests
that previous macro-scale biogeochemical models using a grid-cell-mean WTD
scheme might have underestimated the regional CH4 emissions. The spatial
scale-dependent effects of WTD should be considered in future quantification
of regional CH4 emissions. |
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