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| Titel |
Retrieval and satellite intercomparison of O3 measurements from ground-based FTIR Spectrometer at Equatorial Station: Addis Ababa, Ethiopia |
| VerfasserIn |
S. Takele Kenea, G. Mengistu Tsidu, T. Blumenstock, F. Hase, T. Clarmann, G. P. Stiller |
| 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 ; 6, no. 2 ; Nr. 6, no. 2 (2013-02-28), S.495-509 |
| Datensatznummer |
250017813
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| Publikation (Nr.) |
 copernicus.org/amt-6-495-2013.pdf |
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| Zusammenfassung |
| Since May 2009, high-resolution Fourier Transform Infrared (FTIR) solar
absorption spectra have been recorded at Addis Ababa (9.01° N
latitude, 38.76° E longitude, 2443 m altitude above sea level),
Ethiopia. The vertical profiles and total column amounts of ozone (O3)
are deduced from the spectra by using the retrieval code PROFFIT (V9.5) and
regularly determined instrumental line shape (ILS). A detailed error analysis
of the O3 retrieval is performed. Averaging kernels of the target gas
shows that the major contribution to the retrieved information comes from the
measurement. The degrees of freedom for signals is found to be 2.1 on average
for the retrieval of O3 from the observed FTIR spectra. The ozone Volume
Mixing Ratio (VMR) profiles and column amounts retrieved from FTIR spectra
are compared with the coincident satellite observations of Microwave Limb
Sounding (MLS), Michelson Interferometer for Passive Atmospheric Sounding
(MIPAS), Tropospheric Emission Spectrometer (TES), Ozone Monitoring
Instrument (OMI), Atmospheric Infrared Sounding (AIRS) and Global Ozone
Monitoring Experiment (GOME-2) instruments. The mean relative differences in
ozone profiles of FTIR from MLS and MIPAS are generally lower than 15%
within the altitude range of 27 to 36 km, whereas difference from TES is
lower than 1%. Comparisons of measurements of column amounts from the satellite
and the ground-based FTIR show very good agreement as exhibited by relative
differences within +0.2% to +2.8% for FTIR versus MLS and GOME-2; and −0.9
to −9.0% for FTIR versus OMI, TES and AIRS. The corresponding standard
deviations are within 2.0 to 2.8% for FTIR versus MLS and GOME-2 comparisons
whereas that of FTIR versus OMI, TES and AIRS are within 3.5 to 7.3%. Thus,
the retrieved O3 VMR and column amounts from a tropical site, Addis
Ababa, is found to exhibit very good agreement with all coincident satellite
observations over an approximate 3-yr period. |
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