Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan
Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-at...
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ftunivwagenin:oai:library.wur.nl:wurpubs/583674 2024-01-14T10:10:45+01:00 Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan Teanby, Nicholas A. Irwin, Patrick G.J. Nixon, Conor A. De Kok, Remco Vinatier, Sandrine Coustenis, Athena Sefton-Nash, Elliot Calcutt, Simon B. Flasar, F.M. 2012 text/html https://research.wur.nl/en/publications/active-upper-atmosphere-chemistry-and-dynamics-from-polar-circula https://doi.org/10.1038/nature11611 en eng https://edepot.wur.nl/548888 https://research.wur.nl/en/publications/active-upper-atmosphere-chemistry-and-dynamics-from-polar-circula doi:10.1038/nature11611 info:eu-repo/semantics/restrictedAccess Wageningen University & Research Nature 491 (2012) 7426 ISSN: 0028-0836 Life Science info:eu-repo/semantics/article Article/Letter to editor info:eu-repo/semantics/publishedVersion 2012 ftunivwagenin https://doi.org/10.1038/nature11611 2023-12-20T23:18:41Z Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-atmosphere circulation has been thought to lie at an altitude of 450 to 500 kilometres, where there is a layer of haze that appears to be separated from the main haze deck. This 'detached' haze was previously explained as being due to the co-location of peak haze production and the limit of dynamical transport by the circulation's upper branch. Here we report a build-up of trace gases over the south pole approximately two years after observing the 2009 post-equinox circulation reversal, from which we conclude that middle-atmosphere circulation must extend to an altitude of at least 600 kilometres. The primary drivers of this circulation are summer-hemisphere heating of haze by absorption of solar radiation and winter-hemisphere cooling due to infrared emission by haze and trace gases; our results therefore imply that these effects are important well into the thermosphere (altitudes higher than 500 kilometres). This requires both active upper-atmosphere chemistry, consistent with the detection of high-complexity molecules and ions at altitudes greater than 950 kilometres, and an alternative explanation for the detached haze, such as a transition in haze particle growth from monomers to fractal structures. Article in Journal/Newspaper South pole Wageningen UR (University & Research Centre): Digital Library South Pole Nature 491 7426 732 735 |
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Open Polar |
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Wageningen UR (University & Research Centre): Digital Library |
op_collection_id |
ftunivwagenin |
language |
English |
topic |
Life Science |
spellingShingle |
Life Science Teanby, Nicholas A. Irwin, Patrick G.J. Nixon, Conor A. De Kok, Remco Vinatier, Sandrine Coustenis, Athena Sefton-Nash, Elliot Calcutt, Simon B. Flasar, F.M. Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
topic_facet |
Life Science |
description |
Saturn's moon Titan has a nitrogen atmosphere comparable to Earth's, with a surface pressure of 1.4 bar. Numerical models reproduce the tropospheric conditions very well but have trouble explaining the observed middle-atmosphere temperatures, composition and winds. The top of the middle-atmosphere circulation has been thought to lie at an altitude of 450 to 500 kilometres, where there is a layer of haze that appears to be separated from the main haze deck. This 'detached' haze was previously explained as being due to the co-location of peak haze production and the limit of dynamical transport by the circulation's upper branch. Here we report a build-up of trace gases over the south pole approximately two years after observing the 2009 post-equinox circulation reversal, from which we conclude that middle-atmosphere circulation must extend to an altitude of at least 600 kilometres. The primary drivers of this circulation are summer-hemisphere heating of haze by absorption of solar radiation and winter-hemisphere cooling due to infrared emission by haze and trace gases; our results therefore imply that these effects are important well into the thermosphere (altitudes higher than 500 kilometres). This requires both active upper-atmosphere chemistry, consistent with the detection of high-complexity molecules and ions at altitudes greater than 950 kilometres, and an alternative explanation for the detached haze, such as a transition in haze particle growth from monomers to fractal structures. |
format |
Article in Journal/Newspaper |
author |
Teanby, Nicholas A. Irwin, Patrick G.J. Nixon, Conor A. De Kok, Remco Vinatier, Sandrine Coustenis, Athena Sefton-Nash, Elliot Calcutt, Simon B. Flasar, F.M. |
author_facet |
Teanby, Nicholas A. Irwin, Patrick G.J. Nixon, Conor A. De Kok, Remco Vinatier, Sandrine Coustenis, Athena Sefton-Nash, Elliot Calcutt, Simon B. Flasar, F.M. |
author_sort |
Teanby, Nicholas A. |
title |
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
title_short |
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
title_full |
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
title_fullStr |
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
title_full_unstemmed |
Active upper-atmosphere chemistry and dynamics from polar circulation reversal on Titan |
title_sort |
active upper-atmosphere chemistry and dynamics from polar circulation reversal on titan |
publishDate |
2012 |
url |
https://research.wur.nl/en/publications/active-upper-atmosphere-chemistry-and-dynamics-from-polar-circula https://doi.org/10.1038/nature11611 |
geographic |
South Pole |
geographic_facet |
South Pole |
genre |
South pole |
genre_facet |
South pole |
op_source |
Nature 491 (2012) 7426 ISSN: 0028-0836 |
op_relation |
https://edepot.wur.nl/548888 https://research.wur.nl/en/publications/active-upper-atmosphere-chemistry-and-dynamics-from-polar-circula doi:10.1038/nature11611 |
op_rights |
info:eu-repo/semantics/restrictedAccess Wageningen University & Research |
op_doi |
https://doi.org/10.1038/nature11611 |
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Nature |
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491 |
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7426 |
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732 |
op_container_end_page |
735 |
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1788065562510753792 |