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| Titel |
Inverse modelling of European N2O emissions: assimilating observations from different networks |
| VerfasserIn |
M. Corazza, P. Bergamaschi, A. T. Vermeulen, T. Aalto, L. Haszpra, F. Meinhardt, S. O'Doherty, R. Thompson, J. Moncrieff, E. Popa, M. Steinbacher, A. Jordan, E. Dlugokencky, C. Brühl, M. Krol, F. Dentener |
| 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 ; 11, no. 5 ; Nr. 11, no. 5 (2011-03-15), S.2381-2398 |
| Datensatznummer |
250009464
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| Publikation (Nr.) |
 copernicus.org/acp-11-2381-2011.pdf |
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| Zusammenfassung |
We describe the setup and first results of an inverse modelling system for
atmospheric N2O, based on a four-dimensional variational (4DVAR)
technique and the atmospheric transport zoom model TM5. We focus in this
study on the European domain, utilizing a comprehensive set of
quasi-continuous measurements over Europe, complemented by N2O
measurements from the Earth System Research Laboratory of the National
Oceanic and Atmospheric Administration (NOAA/ESRL) cooperative global air
sampling network. Despite ongoing measurement comparisons among networks
parallel measurements at a limited number of stations show that significant
offsets exist among the different laboratories. Since the spatial gradients
of N2O mixing ratios are of the same order of magnitude as these
biases, the direct use of these biased datasets would lead to significant
errors in the derived emissions. Therefore, in order to also use
measurements with unknown offsets, a new bias correction scheme has been
implemented within the TM5-4DVAR inverse modelling system, thus allowing the
simultaneous assimilation of observations from different networks. The
N2O bias corrections determined in the TM5-4DVAR system agree within
~0.1 ppb (dry-air mole fraction) with the bias derived
from the measurements at monitoring stations where parallel NOAA discrete air samples are
available. The N2O emissions derived for the northwest European
and east European countries for 2006 show good agreement with
the bottom-up emission inventories reported to the United Nations Framework Convention on Climate
Change (UNFCCC). Moreover, the inverse model can significantly narrow the
uncertainty range reported in N2O emission inventories for
these countries, while the lack of measurements does not allow to reduce the
uncertainties of emission estimates in southern Europe.
Several sensitivity experiments were performed to test the robustness of the
results. It is shown that also inversions without detailed a priori
spatio-temporal emission distributions are capable to reproduce major
regional emission patterns within the footprint of the existing atmospheric
network, demonstrating the strong constraints of the atmospheric
observations on the derived emissions. |
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