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| Titel |
Water Vapour in the Atmospheres of Uranus and Neptune Observed with the PACS and HIFI Instrument of the Herschel Space Observatory |
| VerfasserIn |
Christopher Jarchow, Paul Hartogh, Emmanuel Lellouch, Raphaël Moreno, Helmut Feuchtgruber, Thibault Cavalié |
| Konferenz |
EGU General Assembly 2011
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 13 (2011) |
| Datensatznummer |
250053122
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| Zusammenfassung |
| As part of the guaranteed time key programme "Water and related chemistry in the
Solar System" (KP-GT HssO) twenty five different rotational water vapour transitions
have been observed in the atmospheres of Uranus and Neptune with the PACS instrument
of the European Space Agency's Herschel Space Observatory. For both planets these
data are supplemented with a spectrum of the 110-101 ground-state transition at
557 GHz observed with the Herschel/HIFI instrument at the very high resolution of
1 MHz. The initial retrieval of vertical water vapour profiles from these data
using a line-by-line radiation transfer model in combination with the Optimal
Estimation Method as retrieval technique showed an instable convergence of the
iterative fit process and strong artificial oscillations of the profiles. These
difficulties are essentially caused by a too weak regularization of the ill-posed
fit problem; on the other hand a stronger regularization would confine the retrieved
profiles too close to the apriori profile which leads to a significantly bad fit of
the observed spectra. However, using a parameterized water vapour profile with only
a few fit parameters leads to stable and physically meaningful profiles for both
planets. We present details about the different retrieval approaches and the
corresponding results. |
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