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| Titel |
New concepts for the comparison of tropospheric NO2 column densities derived from car-MAX-DOAS observations, OMI satellite observations and the regional model CHIMERE during two MEGAPOLI campaigns in Paris 2009/10 |
| VerfasserIn |
R. Shaiganfar, S. Beirle, H. Petetin, Q. Zhang, M. Beekmann, T. Wagner |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1867-1381
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| Digitales Dokument |
URL |
| Erschienen |
In: Atmospheric Measurement Techniques ; 8, no. 7 ; Nr. 8, no. 7 (2015-07-16), S.2827-2852 |
| Datensatznummer |
250116483
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| Publikation (Nr.) |
 copernicus.org/amt-8-2827-2015.pdf |
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| Zusammenfassung |
| We compare tropospheric column densities (vertically
integrated concentrations) of NO2 from three data sets for the
metropolitan area of Paris during two extensive measurement campaigns (25 days
in summer 2009 and 29 days in winter 2010) within the European research
project MEGAPOLI. The selected data sets comprise a regional chemical
transport model (CHIMERE) as well as two observational data sets: ground-based mobile Multi-AXis-Differential Optical Absorption Spectroscopy
(car-MAX-DOAS) measurements and satellite measurements from the Ozone
Monitoring Instrument (OMI). On most days, car-MAX-DOAS measurements were
carried out along large circles (diameter ~ 35 km) around
Paris. The car-MAX-DOAS results are compared to coincident data from CHIMERE
and OMI. All three data sets have their specific strengths and weaknesses,
especially with respect to their spatiotemporal resolution and coverage as
well as their uncertainties. Thus we compare them in two different ways:
first, we simply consider the original data sets. Second, we compare
modified versions making synergistic use of the complementary information
from different data sets. For example, profile information from the regional
model is used to improve the satellite data, observations of the horizontal
trace gas distribution are used to adjust the respective spatial patterns of
the model simulations, or the model is used as a transfer tool to bridge the
spatial scales between car-MAX-DOAS and satellite observations. Using the
modified versions of the data sets, the comparison results substantially
improve compared to the original versions. In general, good agreement
between the data sets is found outside the emission plume, but inside the
emission plumes the tropospheric NO2 vertical column densities (VCDs). are systematically
underestimated by the CHIMERE model and the satellite observations (compared
to the car-MAX-DOAS observations). One major result from our study is that
for satellite validation close to strong emission sources (like power plants
or megacities), detailed information about the intra-pixel heterogeneity is
essential. Such information may be gained from simultaneous car-MAX-DOAS
measurements using multiple instruments or by combining (car-) MAX-DOAS
measurements with results from regional model simulations. |
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