Comparing methane and temperature profiles on Titan in 1980 and 2005

C. P. McKay, C. A. Griffith, F. Ferri, M. Fulchignoni

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

The Huygens Probe data provided a direct measurement of CH4, temperature, and pressure in Titan's atmosphere. This data can be used to compare to the Voyager data in which the effects of CH4, temperature, and pressure were mixed together. Comparison with Huygens data indicates that values of the surface relative humidity of CH4 at the Voyager ingress and egress were between 20% and 45%, and values above 60% are inconsistent with this comparison. The most parsimonious explanation for the Voyager data is that the temperature and CH4 surface humidity at the Voyager ingress and egress profiles were identical to the Huygens values; a surface temperature of 93.65±0.25 K, and a surface relative humidity of 43%. Thus, it is likely that these values have characterized the equatorial region of Titan from 1980 until 2005. The small reduction of 1 K, between the tropopause temperatures of the Voyager profiles and the tropopause temperature of the Huygens profile is explainable by a change in the antigreenhouse flux from the stratosphere from 0.13 to 0.1 of the total average solar flux. This could result from a small seasonal change in the optical properties of the stratospheric haze.

Original languageEnglish (US)
Pages (from-to)1996-2000
Number of pages5
JournalPlanetary and Space Science
Volume57
Issue number14-15
DOIs
StatePublished - Dec 1 2009

Keywords

  • Huygens
  • Methane
  • Temperature
  • Titan
  • Voyager

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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