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Titel |
High-resolution NO2 remote sensing from the Airborne Prism EXperiment (APEX) imaging spectrometer |
VerfasserIn |
C. Popp, D. Brunner, A. Damm, M. Roozendael, C. Fayt, B. Buchmann |
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 ; 5, no. 9 ; Nr. 5, no. 9 (2012-09-13), S.2211-2225 |
Datensatznummer |
250003087
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Publikation (Nr.) |
copernicus.org/amt-5-2211-2012.pdf |
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Zusammenfassung |
We present and evaluate the retrieval of high spatial resolution maps of
NO2 vertical column densities (VCD) from the Airborne Prism EXperiment
(APEX) imaging spectrometer. APEX is a novel instrument providing airborne
measurements of unique spectral and spatial resolution and coverage as well
as high signal stability. In this study, we use spectrometer data acquired
over Zurich, Switzerland, in the morning and late afternoon during a flight
campaign on a cloud-free summer day in June 2010. NO2 VCD are derived
with a two-step approach usually applied to satellite NO2 retrievals,
i.e. a DOAS analysis followed by air mass factor calculations based on
radiative transfer computations. Our analysis demonstrates that APEX is clearly sensitive to NO2
VCD above typical European tropospheric background abundances
(>1 × 1015 molec cm−2). The two-dimensional maps of NO2
VCD reveal a very convincing spatial distribution with strong gradients around
major NOx sources (e.g. Zurich airport, waste incinerator, motorways)
and low NO2 in remote areas. The morning overflights resulted in
generally higher NO2 VCD and a more distinct pattern than the afternoon
overflights which can be attributed to the meteorological conditions prevailing
during that day with stronger winds and hence larger dilution in the afternoon. The
remotely sensed NO2 VCD are also in reasonably good agreement with ground-based
in-situ measurements from air quality networks considering the limitations of comparing
column integrals with point measurements. Airborne NO2 remote sensing using APEX
will be valuable to detect NO2 emission sources, to provide input for NO2 emission
modelling, and to establish links between in-situ measurements, air quality models,
and satellite NO2 products. |
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