 |
| Titel |
Estimation of volatile organic compound emissions for Europe using data assimilation |
| VerfasserIn |
M. R. Koohkan, M. Bocquet, Y. Roustan, Y. Kim, C. Seigneur |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 12 ; Nr. 13, no. 12 (2013-06-18), S.5887-5905 |
| Datensatznummer |
250018709
|
| Publikation (Nr.) |
 copernicus.org/acp-13-5887-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| The emissions of non-methane volatile organic compounds (VOCs) over western
Europe for the year 2005 are estimated via inverse modelling by assimilation
of in situ observations of concentration and then subsequently compared to
a standard emission inventory. The study focuses on 15 VOC species: five
aromatics, six alkanes, two alkenes, one alkyne and one biogenic diene. The
inversion relies on a validated fast adjoint of the chemical transport model
used to simulate the fate and transport of these VOCs. The assimilated
ground-based measurements over Europe are provided by the European Monitoring
and Evaluation Programme (EMEP) network. The background emission errors and
the prior observational errors are estimated by maximum-likelihood approaches.
The positivity assumption on the VOC emission fluxes is pivotal for a
successful inversion, and this maximum-likelihood approach consistently
accounts for the positivity of the fluxes. For most species, the retrieved
emissions lead to a significant reduction of the bias, which underlines the
misfit between the standard inventories and the observed concentrations. The
results are validated through a forecast test and a cross-validation test. An
estimation of the posterior uncertainty is also provided. It is shown that
the statistically consistent non-Gaussian approach based on a reliable
estimation of the errors offers the best performance. The efficiency in
correcting the inventory depends on the lifetime of the VOCs and the accuracy
of the boundary conditions. In particular, it is shown that the use of in situ
observations using a sparse monitoring network to estimate emissions of
isoprene is inadequate because its short chemical lifetime significantly
limits the spatial radius of influence of the monitoring data. For species
with a longer lifetime (a few days), successful, albeit partial, emission
corrections can reach regions hundreds of kilometres away from the stations.
Domain-wide corrections of the emission inventories of some VOCs are
significant, with underestimations of the order of a factor of 2 for
propane, ethane, ethylene and acetylene. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|