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Vertical profiling of SO_2 and SO above Venus’ clouds by SPICAV/SOIR solar occultations

Belyaev, Denis A. and Montmessin, Franck and Bertaux, Jean-Loup and Mahieux, Arnaud and Fedorova, Anna A. and Korablev, Oleg I. and Marcq, Emmanuel and Yung, Yuk L. and Zhang, Xi (2012) Vertical profiling of SO_2 and SO above Venus’ clouds by SPICAV/SOIR solar occultations. Icarus, 217 (2). pp. 740-751. ISSN 0019-1035. https://resolver.caltech.edu/CaltechAUTHORS:20120229-074752024

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Abstract

New measurements of sulfur dioxide (SO2) and monoxide (SO) in the atmosphere of Venus by SPICAV/SOIR instrument onboard Venus Express orbiter provide ample statistics to study the behavior of these gases above Venus’ clouds. The instrument (a set of three spectrometers) is capable to sound atmospheric structure above the clouds in several observation modes (nadir, solar and stellar occultations) either in the UV or in the near IR spectral ranges. We present the results from solar occultations in the absorption ranges of SO_2 (190–230 nm, and at 4 μm) and SO (190–230 nm). The dioxide was detected by the SOIR spectrometer at the altitudes of 65–80 km in the IR and by the SPICAV spectrometer at 85–105 km in the UV. The monoxide’s absorption was measured only by SPICAV at 85–105 km. We analyzed 39 sessions of solar occultation, where boresights of both spectrometers are oriented identically, to provide complete vertical profiling of SO_2 of the Venus’ mesosphere (65–105 km). Here we report the first firm detection and measurements of two SO_2 layers. In the lower layer SO_2 mixing ratio is within 0.02–0.5 ppmv. The upper layer, also conceivable from microwave measurements by Sandor et al. (Sandor, B.J., Todd Clancy, R., Moriarty-Schieven, G., Mills, F.P. [2010]. Icarus 208, 49–60) is characterized by SO_2 increasing with the altitude from 0.05 to 2 ppmv, and the [SO_2]/[SO] ratio varying from 1 to 5. The presence of the high-altitude SO_x species could be explained by H_2SO_4 photodissociation under somewhat warmer temperature conditions in Venus mesosphere. At 90–100 km the content of the sulfur dioxide correlates with temperature increasing from 0.1 ppmv at 165–170 K to 0.5–1 ppmv at 190–192 K. It supports the hypothesis of SO_2 production by the evaporation of H_2SO_4 from droplets and its subsequent photolysis at around 100 km.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1016/j.icarus.2011.09.025DOIUNSPECIFIED
http://www.sciencedirect.com/science/article/pii/S0019103511003770PublisherUNSPECIFIED
ORCID:
AuthorORCID
Yung, Yuk L.0000-0002-4263-2562
Additional Information:© 2011 Elsevier Inc. Available online 5 October 2011. Venus Express is a space mission from the European Space Agency (ESA). We wish to thank all ESA members who participated in this successful mission, and in particular H. Svedhem and D. Titov. We also thank Astrium for the design and construction of the spacecraft. We thank our collaborators at LATMOS/France, BIRA/Belgium and IKI/Russia for the design and fabrication of the instrument. We thank CNRS and CNES for funding SPICAV/SOIR in France, the Belgian Federal Science Policy Office, the European Space Agency (ESA, PRODEX program), Roscosmoc and the Russian Academy of Sciences. Oleg Korablev and Anna Fedorova acknowledge support from RFBR Grant # 10-02-93116. Denis Belyaev acknowledges support from CNES for a post-doc position at LATMOS. Xi Zhang and Yuk L. Yung were supported by NASA Grant NNX07AI63G to the California Institute of Technology.
Funders:
Funding AgencyGrant Number
CNRS (France)UNSPECIFIED
CNES (France)UNSPECIFIED
Belgian Federal Science Policy OfficeUNSPECIFIED
European Space AgencyUNSPECIFIED
RFBR Grant10-02-93116
NASANNX07AI63G
Russian Academy of SciencesUNSPECIFIED
RoscosmocUNSPECIFIED
Subject Keywords:Venus Venus, Atmosphere Spectroscopy Photochemistry
Issue or Number:2
Record Number:CaltechAUTHORS:20120229-074752024
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20120229-074752024
Official Citation:Denis A. Belyaev, Franck Montmessin, Jean-Loup Bertaux, Arnaud Mahieux, Anna A. Fedorova, Oleg I. Korablev, Emmanuel Marcq, Yuk L. Yung, Xi Zhang, Vertical profiling of SO2 and SO above Venus’ clouds by SPICAV/SOIR solar occultations, Icarus, Volume 217, Issue 2, February 2012, Pages 740-751, ISSN 0019-1035, 10.1016/j.icarus.2011.09.025. (http://www.sciencedirect.com/science/article/pii/S0019103511003770)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:29514
Collection:CaltechAUTHORS
Deposited By: Ruth Sustaita
Deposited On:29 Feb 2012 17:19
Last Modified:09 Mar 2020 13:19

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