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| Titel |
Spectral inventory of the SOIR spectra onboard Venus Express |
| VerfasserIn |
Séverine Robert, Arnaud Mahieux, Valerie Wilquet, Rachel Drummond, Ann Carine Vandaele |
| Konferenz |
EGU General Assembly 2013
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075558
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| Zusammenfassung |
| The set of spectra recorded by the SOIR instrument on board Venus Express have been
carefully studied from a spectroscopic point of view. The SOIR instrument combines an
echelle spectrometer and an Acousto-Optical Tunable Filter for order selection.
It performs solar occultation measurements in the IR region (2.2 - 4.4 μm) at a
resolution of 0.10 - 0.24 cm-1 [1]. The wavelength range probed by SOIR allows a
detailed chemical inventory of the Venus atmosphere above the cloud layer (65 to 180
km) with emphasis on the vertical distribution of gases (CO2, CO, H2O, HCl, HF,
-¦).
The sensitivity of the SOIR instrument and the high concentration of CO2 on Venus,
coupled with the long absorption paths sounded during solar occultations, enable us to detect
weak absorption bands of rare CO2 isotopologues [2, 3].
The spectra are analysed using ASIMAT, an in-house Matlab algorithm [4]. It is based on
the Optimal Estimation Method [5] with the aim to deduce physical characteristics
(densities, temperature) of the Venus atmosphere from the spectra recorded using
SOIR.
The spectra were fitted using HITRAN 2008 [6]. A tool of automatic assignment was
developed and applied to each spectrum leading to the creation of the wavenumber list of
each line visible in the SOIR spectra.
The tools used to calibrate the spectra, to characterize the residuals and to produce the
line list will be described extensively for a selected number of orbits.
References
1. Nevejans, D., et al., Compact high-resolution space-borne echelle grating spectrometer
with AOTF based on order sorting for the infrared domain from 2.2 to 4.3 micrometer.
Applied Optics, 2006. 45(21): p. 5191-5206.
2. Wilquet, V., et al., Line parameters for the 01111-00001 band of 12C16O18O from
SOIR measurements of the Venus atmosphere. J. Quant. Spectrosc. Radiat. Transfer, 2008.
109: p. 895-905.
3. Robert, S., et al., Assignment and rotational analysis of new absorption bands of
carbon dioxide isotopologues in Venus spectra. J. Quant. Spectrosc. Radiat. Transfer, 2013.
114: p. 29-41.
4. Mahieux, A., et al., Densities and temperatures in the Venus mesosphere and lower
thermosphere retrieved from SOIR onboard Venus Express: Retrieval technique. J. Geophys.
Res., 2010. 115(E12014): p. 10.1029/2010JE003589.
5. Rodgers, C., Inverse methods for atmospheric sounding: Theory and practice. World
Scientific, ed. N.J. Hackensack. 2000: University of Oxford.
6. Rothman, L.S., et al., The HITRAN 2008 molecular spectroscopic database. J. Quant.
Spectrosc. Radiat. Transfer, 2009. 110(9-10): p. 533-572. |
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