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| Titel |
OClO slant column densities derived from GOMOS averaged transmittance measurements |
| VerfasserIn |
C. Tetard, D. Fussen, F. Vanhellemont, C. Bingen, E. Dekemper, N. Mateshvili, D. Pieroux, C. Robert, E. Kyrölä, J. Tamminen, V. Sofieva, A. Hauchecorne, F. Dalaudier, J.-L. Bertaux, O. Fanton d'Andon, G. Barrot, L. Blanot, A. Dehn, L. Saavedra de Miguel |
| 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. 11 ; Nr. 6, no. 11 (2013-11-04), S.2953-2964 |
| Datensatznummer |
250085100
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| Publikation (Nr.) |
 copernicus.org/amt-6-2953-2013.pdf |
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| Zusammenfassung |
| The Global Ozone Monitoring by Occultation of Stars (GOMOS) instrument on
board the European platform ENVISAT (ENVironment SATellite) was dedicated to the study of the
of Earth's atmosphere using the stellar occultation technique. The spectral
range of the GOMOS spectrometer extends from the UV (ultra violet) to the near infrared,
allowing for the retrieval of species such as O3, NO2, NO3, H2O,
O2, air density, aerosol extinction and OClO. Nevertheless, OClO cannot
be retrieved using a single GOMOS measurement because of the weak
signal-to-noise ratio and the small optical thickness associated with this
molecule. We present here the method used to detect this molecule by using
several GOMOS measurements. It is based on a two-step approach. First,
several co-located measurements are combined in a statistical way to build an
averaged measurement with a higher signal-to-noise ratio; then, a
differential optical absorption spectroscopy (DOAS) method is applied to
retrieve OClO slant column densities (SCD). The statistics of the sets of
GOMOS measurements used to build the averaged measurement and the spectral
window selection are analyzed. The obtained retrievals are compared to
results from two balloon-borne instruments. It appears that the
inter-comparisons of OClO are generally satisfying (relative differences are
about 15–60%). Two nighttime climatologies of OClO based on
GOMOS averaged measurements are presented. The first depicts annual global
pictures of OClO from 2003 to 2011. From this climatology, the presence of an
OClO SCD peak in the equatorial region at about 35 km is confirmed and
strong OClO SCD in both polar regions are observed (more than
1016 cm−2 in the Antarctic region and slightly less in the
Arctic region), a sign of chlorine activation. The second climatology is a
monthly time series. It clearly shows the chlorine activation of the lower
stratosphere during winter. Moreover the equatorial OClO SCD peak is observed
during all years without any significant variations. This very promising
method, applied on GOMOS measurements, allowed us to build the first
nighttime climatology of OClO using limb-viewing instruments. |
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