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3 - Thermal structure of Titan's troposphere and middle atmosphere

Published online by Cambridge University Press:  05 January 2014

By
F. M. Flasar ,
R. K. Achterberg  and
P. J. Schinder
Edited by
Ingo Müller-Wodarg ,
Caitlin A. Griffith ,
Emmanuel Lellouch  and
Thomas E. Cravens
F. M. Flasar
Affiliation:
NASA/Goddard Space Flight Center
R. K. Achterberg
Affiliation:
University of Maryland
P. J. Schinder
Affiliation:
Cornell University
Ingo Müller-Wodarg
Affiliation:
Imperial College London
Caitlin A. Griffith
Affiliation:
University of Arizona
Emmanuel Lellouch
Affiliation:
Observatoire de Paris, Meudon
Thomas E. Cravens
Affiliation:
University of Kansas
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Summary

3.1 Introduction

The thermal structure of an atmosphere is a product of radiative processes and dynamical transports. Indeed, the study of the distribution of temperature and pressure (as well as of winds and humidity) and its temporal behavior has played a key role in the development of terrestrial meteorology (Brunt, 1939). The distribution of gaseous constituents, produced by photo- or ion-chemistry, can affect atmospheric temperatures, if the gases are radiatively active, as does the distribution of clouds and aerosols. The redistribution of trace gases, clouds, and aerosols by atmospheric motions can materially affect an atmosphere's thermal structure.

Like Earth, Titan has a well defined troposphere, stratosphere, and mesosphere (the latter two layers comprise the middle atmosphere). Figure 3.1 depicts representative temperature profiles for the two atmospheres. Barometric pressure is used as the vertical coordinate. In these units the terrestrial and Titan profiles look roughly similar, except that Earth is much warmer, and its stratopause is at a higher pressure. Were the two sets of profiles depicted using geometric height instead of pressure as the vertical coordinate, Titan's temperature profile would look much more extended. This is mainly because its surface gravitational acceleration (g = 1.34 m s-2) is 14 percent that of Earth. Indeed, because Titan's atmosphere is so extended, the decrease of gravity with altitude matters.

Type
Chapter
Information
Titan
Interior, Surface, Atmosphere, and Space Environment
 , pp. 102 - 121
Publisher: Cambridge University Press
Print publication year: 2014

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