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| Titel |
Improving estimates of N2O emissions for western and central Europe using a Bayesian inversion approach |
| VerfasserIn |
R. L. Thompson, C. Gerbig, C. Roedenbeck, M. Heimann |
| Konferenz |
EGU General Assembly 2009
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 11 (2009) |
| Datensatznummer |
250030049
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| Zusammenfassung |
| The nitrous oxide (N2O) mixing ratio has been increasing in the atmosphere since the
industrial revolution, from 270 ppb in 1750 to 320 ppb in 2007 with a steady growth rate of
around 0.26% since the early 1980’s. The increase in N2O is worrisome for two main
reasons. First, it is a greenhouse gas; this means that its atmospheric increase translates to an
enhancement in radiative forcing of 0.16 ± 0.02 Wm-2 making it currently the fourth most
important long-lived greenhouse gas and is predicted to soon overtake CFC’s to become the
third most important. Second, it plays an important role in stratospheric ozone chemistry.
Human activities are the primary cause of the atmospheric N2O increase. The largest
anthropogenic source of N2O is from the use of N-fertilizers in agriculture but fossil fuel
combustion and industrial processes, such as adipic and nitric acid production, are also
important.
We present a Bayesian inversion approach for estimating N2O fluxes over central and western
Europe using high frequency in-situ concentration data from the Ochsenkopf tall tower
(50-01-²N, 11-48-², 1022 masl). For the inversion, we employ a Lagrangian-type
transport model, STILT, which provides source-receptor relationships at 10 km
using ECMWF meteorological data. The a priori flux estimates used were from
IER, for anthropogenic, and GEIA, for natural fluxes. N2O fluxes were retrieved
monthly at 2 x 2 degree spatial resolution for 2007. The retrieved N2O fluxes showed
significantly more spatial heterogeneity than in the a priori field and considerable seasonal
variability. The timing of peak emissions was different for different regions but in
general the months with the strongest emissions were May and August. Overall,
the retrieved flux (anthropogenic and natural) was lower than in the a priori field. |
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