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The evolution of Titan's cold south polar cloud
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  • Lavender Elle Hanson,
  • Robert S. French,
  • Darryn W. Waugh,
  • Erika Barth,
  • Carrie Marie Anderson
Lavender Elle Hanson
Johns Hopkins University

Corresponding Author:[email protected]

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Robert S. French
SETI Institute
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Darryn W. Waugh
Johns Hopkins University
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Erika Barth
Southwest Research Institute Boulder
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Carrie Marie Anderson
NASA GSFC
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Abstract

Early during Titan’s southern fall, images captured by Cassini’s Imaging Science Subsystem (ISS) revealed the formation of a large cloud above Titan’s south pole. Subsequent analysis of Cassini data revealed the cloud contained HCN ice, but the cloud’s evolution has not been examined. We reviewed imagery of Titan’s south pole between 2012 and the end of mission at Ls=93°. We find evidence of cloud formation as early as Ls=32° (April 2012), one terrestrial month earlier than previously reported, after which the cloud persists until Ls=79° (mid 2016). The cloud top altitude descended from about 320 km at Ls=32° to below 230 km by Ls=79°, at which point it became obscured by atmospheric methane absorption. The cloud also grew laterally; initially confined poleward of 81°S, by Ls=75° the cloud extended as far as 64.5°S. These measurements place new constraints on Titan’s polar stratospheric temperature structure and circulation during southern fall.
09 Nov 2024Submitted to ESS Open Archive
13 Nov 2024Published in ESS Open Archive