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| Titel |
Influence of low spatial resolution a priori data on tropospheric NO2 satellite retrievals |
| VerfasserIn |
A. Heckel, S.-W. Kim, G. J. Frost, A. Richter, M. Trainer, J. P. Burrows |
| 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 ; 4, no. 9 ; Nr. 4, no. 9 (2011-09-09), S.1805-1820 |
| Datensatznummer |
250002091
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| Publikation (Nr.) |
 copernicus.org/amt-4-1805-2011.pdf |
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| Zusammenfassung |
| The retrieval of tropospheric columns of NO2 and other trace gases from
satellite observations of backscattered solar radiation relies on the use of
accurate a priori information. The spatial resolution of current space
sensors is often significantly higher than that of the a priori datasets
used, introducing uncertainties from spatial misrepresentation. In this
study, the effect of spatial under-sampling of a priori data on the
retrieval of NO2 columns was studied for a typical coastal area (around
San Francisco). High-resolution (15 × 15 km2) NO2 a priori data
from the WRF-Chem model in combination with high-resolution MODIS surface
reflectance and aerosol data were used to investigate the uncertainty
introduced by applying a priori data at typical global chemical transport
model resolution. The results show that the relative uncertainties can be
large (more than a factor of 2 if all a priori data used is at the coarsest
resolution) for individual measurements, mainly due to spatial variations in
NO2 profile and surface albedo, with smaller contributions from
aerosols and surface height changes. Similar sensitivities are expected for
other coastal regions and localised sources such as power plants,
highlighting the need for high-resolution a priori data in quantitative
analysis of the spatial patterns retrieved from satellite observations of
tropospheric pollution. |
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