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Titel |
Estimating regional greenhouse gas fluxes: an uncertainty analysis of planetary boundary layer techniques and bottom-up inventories |
VerfasserIn |
X. Zhang, X. Lee, T. J. Griffis, J. M. Baker, W. Xiao |
Medientyp |
Artikel
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Sprache |
Englisch
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ISSN |
1680-7316
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Digitales Dokument |
URL |
Erschienen |
In: Atmospheric Chemistry and Physics ; 14, no. 19 ; Nr. 14, no. 19 (2014-10-10), S.10705-10719 |
Datensatznummer |
250119092
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Publikation (Nr.) |
copernicus.org/acp-14-10705-2014.pdf |
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Zusammenfassung |
Quantification of regional greenhouse gas (GHG) fluxes is essential for
establishing mitigation strategies and evaluating their effectiveness. Here,
we used multiple top-down approaches and multiple trace gas observations at
a tall tower to estimate regional-scale GHG fluxes and evaluate the GHG
fluxes derived from bottom-up approaches. We first applied the eddy
covariance, equilibrium, inverse modeling (CarbonTracker), and flux
aggregation methods using 3 years of carbon dioxide (CO2)
measurements on a 244 m tall tower in the upper Midwest, USA. We then
applied the equilibrium method for estimating CH4 and N2O fluxes
with 1-month high-frequency CH4 and N2O gradient measurements on
the tall tower and 1-year concentration measurements on a nearby tall
tower, and evaluated the uncertainties of this application. The results
indicate that (1) the flux aggregation, eddy covariance, the equilibrium
method, and the CarbonTracker product all gave similar seasonal patterns of
the regional CO2 flux (105−106 km2, but that the
equilibrium method underestimated the July CO2 flux by 52–69%.
(2) The annual budget varied among these methods from −54 to −131 g C–CO2 m−2 yr−1,
indicating a large uncertainty in the annual CO2 flux estimation.
(3) The regional CH4 and N2O emissions according
to a top-down method were at least 6 and 2 times higher than the
emissions from a bottom-up inventory (Emission Database for Global
Atmospheric Research), respectively. (4) The global warming potentials of the
CH4 and N2O emissions were equal in magnitude to the cooling
benefit of the regional CO2 uptake. The regional GHG budget, including
both biological and anthropogenic origins, is estimated at
7 ± 160 g CO2 equivalent m−2 yr−1. |
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