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| Titel |
Estimates of black carbon emissions in the western United States using the GEOS-Chem adjoint model |
| VerfasserIn |
Y. H. Mao, Q. B. Li, D. K. Henze, Z. Jiang, D. B. A. Jones, M. Kopacz, C. He, L. Qi, M. Gao, W.-M. Hao, K.-N. Liou |
| 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 ; 15, no. 13 ; Nr. 15, no. 13 (2015-07-14), S.7685-7702 |
| Datensatznummer |
250119895
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| Publikation (Nr.) |
 copernicus.org/acp-15-7685-2015.pdf |
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| Zusammenfassung |
| We estimate black carbon (BC) emissions in the western United States for
July–September 2006 by inverting surface BC concentrations from the
Interagency Monitoring of Protected Visual Environments (IMPROVE) network
using a global chemical transport model (GEOS-Chem) and its adjoint. Our
best estimate of the BC emissions is 49.9 Gg at 2° × 2.5° (a factor of 2.1 increase) and 47.3 Gg at 0.5° × 0.667°
(1.9 times increase). Model results now capture
the observed major fire episodes with substantial bias reductions
(~ 35 % at 2° × 2.5° and
~ 15 % at 0.5° × 0.667°). The
emissions are ~ 20–50 % larger than those from our earlier
analytical inversions (Mao et al., 2014). The discrepancy is especially
drastic in the partitioning of anthropogenic versus biomass burning
emissions. The August biomass burning BC emissions are 4.6–6.5 Gg and
anthropogenic BC emissions 8.6–12.8 Gg, varying with the model resolution,
error specifications, and subsets of observations used. On average both
anthropogenic and biomass burning emissions in the adjoint inversions
increase 2-fold relative to the respective {a priori} emissions, in distinct contrast
to the halving of the anthropogenic and tripling of the biomass burning
emissions in the analytical inversions. We attribute these discrepancies to
the inability of the adjoint inversion system, with limited spatiotemporal
coverage of the IMPROVE observations, to effectively distinguish collocated
anthropogenic and biomass burning emissions on model grid scales. This calls
for concurrent measurements of other tracers of biomass burning and fossil
fuel combustion (e.g., carbon monoxide and carbon isotopes). We find that
the adjoint inversion system as is has sufficient information content to
constrain the total emissions of BC on the model grid scales. |
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