CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express

We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3m is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 11...

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Autores: Piccialli, A., López-Valverde, M. A., Maattanen, A., González-Galindo, F., Audouard, J., Altieri, F., Forget, F., Drossart, P., Gondet, B., Bibring, J. P.
Tipo de documento: artigo
Estado:Versão publicada
Data de publicação:2016
País:España
Recursos:Consejo Superior de Investigaciones Científicas (CSIC)
Repositório:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/138012
Acesso em linha:http://hdl.handle.net/10261/138012
Access Level:Acceso aberto
Palavra-chave:Planetary atmospheres
Mars atmosphere
Non-LTE emissions
Remote sensing
Infrared observations
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spelling CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars ExpressPiccialli, A.López-Valverde, M. A.Maattanen, A.González-Galindo, F.Audouard, J.Altieri, F.Forget, F.Drossart, P.Gondet, B.Bibring, J. P.Planetary atmospheresMars atmosphereNon-LTE emissionsRemote sensingInfrared observationsWe report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3m is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110km. The main value of OMEGA observations is that they provide simultaneously spectral information and good spatial sampling of the CO2 emission. In this study we analyzed 98 dayside limb observations spanning over more than 3 Martian years, with a very good latitudinal and longitudinal coverage. Thanks to the precise altitude sounding capabilities of OMEGA, we extracted vertical profiles of the non-local thermodynamic equilibrium (non-LTE) emission at each wavelength and we studied their dependence on several geophysical parameters, such as the solar illumination and the tangent altitude. The dependence of the non-LTE emission on solar zenith angle and altitude follows a similar behavior to that predicted by the non-LTE model. According to our non-LTE model, the tangent altitude of the peak of the CO2 emission varies with the thermal structure, but the pressure level where the peak of the emission is found remains constant at approximate to 0.03 0.01Pa, . This non-LTE model prediction has been corroborated by comparing SPICAM and OMEGA observations. We have shown that the seasonal variations of the altitude of constant pressure levels in SPICAM stellar occultation retrievals correlate well with the variations of the OMEGA peak emission altitudes, although the exact pressure level cannot be defined with the spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in the altitude of the peak emission provide us information on the altitude of the 0.03Pa pressure level. Since the pressure at a given altitude is dictated by the thermal structure below, the tangent altitude of the peak emission represents then an important piece of information of the atmosphere, of great value for validating general circulation models. We thus compared the altitude of OMEGA peak emission with the altitude of the 0.03Pa level predicted by the Laboratoire de meteorologie dynamique (LMD)-Mars global circulation model and found that the peak emission altitudes from OMEGA present a much larger variability than the tangent altitude of the 0.03Pa level predicted by the general circulation model. This variability could be possibly due to unresolved atmospheric waves. Further studies using this strong CO2 limb emission data are proposed.A.P. acknowledges funding from the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement 246556.This work has received funding from the European Union's Horizon 2020 Programme (H2020-Compet-08-2014) under grant agreement UPWARDS-633127.Peer reviewedAmerican Geophysical UnionEuropean CommissionConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]201620162016info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Publisher's versioninfo:eu-repo/semantics/publishedVersionhttp://hdl.handle.net/10261/138012reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE##PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/EC/H2020/633127info:eu-repo/grantAgreement/EC/FP7/246556http://dx.doi.org/10.1002/2015JE004981Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/1380122026-05-22T06:33:51Z
dc.title.none.fl_str_mv CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
title CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
spellingShingle CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
Piccialli, A.
Planetary atmospheres
Mars atmosphere
Non-LTE emissions
Remote sensing
Infrared observations
title_short CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
title_full CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
title_fullStr CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
title_full_unstemmed CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
title_sort CO2 non-LTE limb emissions in Mars' atmosphere as observed by OMEGA/Mars Express
dc.creator.none.fl_str_mv Piccialli, A.
López-Valverde, M. A.
Maattanen, A.
González-Galindo, F.
Audouard, J.
Altieri, F.
Forget, F.
Drossart, P.
Gondet, B.
Bibring, J. P.
author Piccialli, A.
author_facet Piccialli, A.
López-Valverde, M. A.
Maattanen, A.
González-Galindo, F.
Audouard, J.
Altieri, F.
Forget, F.
Drossart, P.
Gondet, B.
Bibring, J. P.
author_role author
author2 López-Valverde, M. A.
Maattanen, A.
González-Galindo, F.
Audouard, J.
Altieri, F.
Forget, F.
Drossart, P.
Gondet, B.
Bibring, J. P.
author2_role author
author
author
author
author
author
author
author
author
dc.contributor.none.fl_str_mv European Commission
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Planetary atmospheres
Mars atmosphere
Non-LTE emissions
Remote sensing
Infrared observations
topic Planetary atmospheres
Mars atmosphere
Non-LTE emissions
Remote sensing
Infrared observations
description We report on daytime limb observations of Mars upper atmosphere acquired by the OMEGA instrument on board the European spacecraft Mars Express. The strong emission observed at 4.3m is interpreted as due to CO2 fluorescence of solar radiation and is detected at a tangent altitude in between 60 and 110km. The main value of OMEGA observations is that they provide simultaneously spectral information and good spatial sampling of the CO2 emission. In this study we analyzed 98 dayside limb observations spanning over more than 3 Martian years, with a very good latitudinal and longitudinal coverage. Thanks to the precise altitude sounding capabilities of OMEGA, we extracted vertical profiles of the non-local thermodynamic equilibrium (non-LTE) emission at each wavelength and we studied their dependence on several geophysical parameters, such as the solar illumination and the tangent altitude. The dependence of the non-LTE emission on solar zenith angle and altitude follows a similar behavior to that predicted by the non-LTE model. According to our non-LTE model, the tangent altitude of the peak of the CO2 emission varies with the thermal structure, but the pressure level where the peak of the emission is found remains constant at approximate to 0.03 0.01Pa, . This non-LTE model prediction has been corroborated by comparing SPICAM and OMEGA observations. We have shown that the seasonal variations of the altitude of constant pressure levels in SPICAM stellar occultation retrievals correlate well with the variations of the OMEGA peak emission altitudes, although the exact pressure level cannot be defined with the spectroscopy for the investigation of the characteristics of the atmosphere of Venus (SPICAM) nighttime data. Thus, observed changes in the altitude of the peak emission provide us information on the altitude of the 0.03Pa pressure level. Since the pressure at a given altitude is dictated by the thermal structure below, the tangent altitude of the peak emission represents then an important piece of information of the atmosphere, of great value for validating general circulation models. We thus compared the altitude of OMEGA peak emission with the altitude of the 0.03Pa level predicted by the Laboratoire de meteorologie dynamique (LMD)-Mars global circulation model and found that the peak emission altitudes from OMEGA present a much larger variability than the tangent altitude of the 0.03Pa level predicted by the general circulation model. This variability could be possibly due to unresolved atmospheric waves. Further studies using this strong CO2 limb emission data are proposed.
publishDate 2016
dc.date.none.fl_str_mv 2016
2016
2016
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Publisher's version
info:eu-repo/semantics/publishedVersion
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/138012
url http://hdl.handle.net/10261/138012
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
#PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/EC/H2020/633127
info:eu-repo/grantAgreement/EC/FP7/246556
http://dx.doi.org/10.1002/2015JE004981
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv American Geophysical Union
publisher.none.fl_str_mv American Geophysical Union
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 15.812429

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