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| Titel |
Modeling uncertainties for tropospheric nitrogen dioxide columns affecting satellite-based inverse modeling of nitrogen oxides emissions |
| VerfasserIn |
J.-T. Lin, Z. Liu, Q. Zhang, H. Liu, J. Mao, G. Zhuang |
| 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 ; 12, no. 24 ; Nr. 12, no. 24 (2012-12-21), S.12255-12275 |
| Datensatznummer |
250011691
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| Publikation (Nr.) |
 copernicus.org/acp-12-12255-2012.pdf |
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| Zusammenfassung |
| Errors in chemical transport models (CTMs) interpreting the relation between
space-retrieved tropospheric column densities of nitrogen dioxide (NO2)
and emissions of nitrogen oxides (NOx) have important consequences on the
inverse modeling. They are however difficult to quantify due to lack of
adequate in situ measurements, particularly over China and other developing
countries. This study proposes an alternate approach for model evaluation
over East China, by analyzing the sensitivity of modeled NO2 columns to
errors in meteorological and chemical parameters/processes important to the
nitrogen abundance. As a demonstration, it evaluates the nested version of
GEOS-Chem driven by the GEOS-5 meteorology and the INTEX-B anthropogenic
emissions and used with retrievals from the Ozone Monitoring Instrument
(OMI) to constrain emissions of NOx. The CTM has been used extensively for
such applications. Errors are examined for a comprehensive set of
meteorological and chemical parameters using measurements and/or uncertainty
analysis based on current knowledge. Results are exploited then for
sensitivity simulations perturbing the respective parameters, as the basis
of the following post-model linearized and localized first-order
modification. It is found that the model meteorology likely contains errors
of various magnitudes in cloud optical depth, air temperature, water vapor,
boundary layer height and many other parameters. Model errors also exist in
gaseous and heterogeneous reactions, aerosol optical properties and
emissions of non-nitrogen species affecting the nitrogen chemistry.
Modifications accounting for quantified errors in 10 selected parameters
increase the NO2 columns in most areas with an average positive impact
of 18% in July and 8% in January, the most important factor being
modified uptake of the hydroperoxyl radical (HO2) on aerosols. This suggests a
possible systematic model bias such that the top-down emissions will be
overestimated by the same magnitude if the model is used for emission
inversion without corrections. The modifications however cannot eliminate
the large model underestimates in cities and other extremely polluted areas
(particularly in the north) as compared to satellite retrievals, likely
pointing to underestimates of the a priori emission inventory in these
places with important implications for understanding of atmospheric
chemistry and air quality. Note that these modifications are simplified and
should be interpreted with caution for error apportionment. |
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