 |
| Titel |
Top-down estimate of surface flux in the Los Angeles Basin using a mesoscale inverse modeling technique: assessing anthropogenic emissions of CO, NOx and CO2 and their impacts |
| VerfasserIn |
J. Brioude, W. M. Angevine, R. Ahmadov, S.-W. Kim, S. Evan, S. A. McKeen, E.-Y. Hsie, G. J. Frost, J. A. Neuman, I. B. Pollack, J. Peischl, T. B. Ryerson, J. Holloway, S. S. Brown, J. B. Nowak, J. M. Roberts, S. C. Wofsy, G. W. Santoni, T. Oda, M. Trainer |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1680-7316
|
| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Chemistry and Physics ; 13, no. 7 ; Nr. 13, no. 7 (2013-04-02), S.3661-3677 |
| Datensatznummer |
250018570
|
| Publikation (Nr.) |
 copernicus.org/acp-13-3661-2013.pdf |
|
|
|
|
|
| Zusammenfassung |
| We present top-down estimates of anthropogenic CO, NOx and
CO2 surface fluxes at mesoscale using a Lagrangian model in
combination with three different WRF model configurations, driven by
data from aircraft flights during the CALNEX campaign in southern
California in May–June 2010. The US EPA National Emission Inventory
2005 (NEI 2005) was the prior in the CO and NOx inversion
calculations. The flux ratio inversion method, based on linear
relationships between chemical species, was used to calculate the
CO2 inventory without prior knowledge of CO2 surface
fluxes. The inversion was applied to each flight to estimate the
variability of single-flight-based flux estimates. In Los Angeles (LA)
County, the uncertainties on CO and NOx fluxes were 10%
and 15%, respectively. Compared with NEI 2005, the CO posterior
emissions were lower by 43% in LA County and
by 37% in the South Coast Air Basin
(SoCAB). NOx posterior emissions were lower by
32% in LA County and by
27% in the SoCAB. NOx posterior
emissions were 40% lower on weekends relative to weekdays. The
CO2 posterior estimates were
183 Tg yr−1 in SoCAB. A flight during ITCT (Intercontinental Transport and Chemical Transformation) in
2002 was used to estimate emissions in the LA Basin in 2002. From 2002
to 2010, the CO and NOx posterior emissions decreased by
41% and 37%, respectively, in agreement with previous
studies. Over the same time period, CO2 emissions increased by
10% in LA County but decreased by
4% in the SoCAB, a statistically
insignificant change. Overall, the posterior estimates were in good
agreement with the California Air Resources Board (CARB) inventory,
with differences of 15% or less. However, the posterior spatial
distribution in the basin was significantly different from CARB for
NOx emissions. WRF-Chem mesoscale chemical-transport model
simulations allowed an evaluation of differences in chemistry using
different inventory assumptions, including NEI 2005, a gridded CARB inventory and the
posterior inventories derived in this study. The biases in WRF-Chem
ozone were reduced and correlations were increased using the posterior
from this study compared with simulations with the two bottom-up
inventories, suggesting that improving the spatial distribution of ozone
precursor surface emissions is also important in mesoscale chemistry
simulations. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|