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A wind origin for Titan's haze structure

Nature volume 418, pages 853–856 (2002)Cite this article

Abstract

Titan, the largest moon of Saturn, is the only satellite in the Solar System with a dense atmosphere. Titan's atmosphere is mainly nitrogen with a surface pressure of 1.5 atmospheres and a temperature of 95 K (ref. 1). A seasonally varying2 haze, which appears to be the main source of heating and cooling that drives atmospheric circulation3,4, shrouds the moon. The haze has numerous features that have remained unexplained. There are several layers5, including a ‘polar hood’6,7,8, and a pronounced hemispheric asymmetry2. The upper atmosphere rotates much faster than the surface of the moon9,10, and there is a significant latitudinal temperature asymmetry at the equinoxes11,12. Here we describe a numerical simulation of Titan's atmosphere, which appears to explain the observed features of the haze. The critical new factor in our model is the coupling of haze formation with atmospheric dynamics, which includes a component of strong positive feedback between the haze and the winds.

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Figure 1: Two-dimensional planetary distribution of haze scaled extinction.
Figure 2: Comparison of the reflected intensity north–south profile between observation and model.
Figure 3: Comparison of latitudinal temperature profiles between observation and model.
Figure 4: Comparison of latitudinal zonal wind profiles between observation and model.

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Acknowledgements

This work was partially supported by the NASA Planetary Atmospheres Program and the French Programme National de Planétologie. P.R. thanks the National Research Council Associateship Program.

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Authors and Affiliations

  1. Service d'Aéronomie, B102, Université de Paris 6/Université de Versailles-St-Quentin, 4 place Jussieu, 75252, Paris Cedex, France

    P. Rannou

  2. Laboratoire de Météorologie Dynamique, Université de Paris 6, 4 place Jussieu, 75252, Paris Cedex, France

    F. Hourdin

  3. NASA-Ames Research Center, Moffett Field, California, 94035, USA

    C. P. McKay

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  1. P. Rannou
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  3. C. P. McKay
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Correspondence to P. Rannou.

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Rannou, P., Hourdin, F. & McKay, C. A wind origin for Titan's haze structure. Nature 418, 853–856 (2002). https://doi.org/10.1038/nature00961

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