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Titel |
Monitoring the lowermost tropospheric ozone with thermal infrared observations from a geostationary platform: performance analyses for a future dedicated instrument |
VerfasserIn |
P. Sellitto, G. Dufour, M. Eremenko, J. Cuesta, G. Foret, B. Gaubert, M. Beekmann, V.-H. Peuch, J.-M. Flaud |
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 ; 7, no. 2 ; Nr. 7, no. 2 (2014-02-06), S.391-407 |
Datensatznummer |
250115593
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Publikation (Nr.) |
copernicus.org/amt-7-391-2014.pdf |
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Zusammenfassung |
In this paper, we present performance analyses for a concept
geostationary observing system called MAGEAQ (Monitoring the
Atmosphere from Geostationary orbit for European Air Quality). The
MAGEAQ mission is designed to include a TIR (thermal infrared) spectrometer and
a broadband VIS (visible) radiometer; in this work we study only the TIR
component (MAGEAQ-TIR). We have produced about 20 days of MAGEAQ-TIR
tropospheric ozone pseudo-observations with a full forward and
inverse radiative transfer pseudo-observations simulator. We have
studied the expected sensitivity of MAGEAQ-TIR and we have found
that it is able to provide a full single piece of information for
the ozone column from surface to 6 km (about
1.0 DOF (degrees of freedom) and maximum sensitivity at about
3.0 km, on average), as well as a partially independent surface–3 km ozone column (about 0.6 DOF and maximum sensitivity at
about 2.5 km, on average). Then, we have compared
the tropospheric ozone profiles and the lower (surface–6 km) and
lowermost (surface–3 km) tropospheric ozone column
pseudo-observations to the target pseudo-reality, produced with the
MOCAGE (MOdèle de Chimie Atmosphérique à Grande Echelle)
chemistry and transport model. We have found very small to not
significant average biases (< 1% in absolute value, for the
surface–6 km TOC (tropospheric ozone column),
and about −2 to −3 %, for the surface–3 km TOC) and small RMSEs (root
mean square errors; about 1.3 DU (5%), for the
surface–6 km TOC, and about 1.5 DU (10%), for the surface–3 km TOC). We have tested the performance of MAGEAQ-TIR at some
selected small (0.2° × 0.2°) urban and rural
locations. We have found that, while the vertical structures of the
lower tropospheric ozone pseudo-reality are sometimes missed,
MAGEAQ-TIR's lower and lowermost column pseudo-observations follow
stunningly good the MOCAGE column pseudo-reality, with correlation
coefficients reaching values of 0.9 or higher. Unprecedented
retrieval performance for the lowermost tropospheric ozone column
is shown. In any case, our MAGEAQ-TIR pseudo-observations are only
partially able to replicate the MOCAGE pseudo-reality variability
and temporal cycle at the very lowest layers (surface and 1 km
altitude), especially at southern European urban locations, where
the photochemistry signal is partially missed or shifted at higher
altitudes. Temporal artifacts on the daily cycle are sometimes
observed. Stratospheric-to-tropospheric exchanges during short time
periods (of the order of 1 day) are detected by the MAGEAQ-TIR
pseudo-observations. |
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