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On the latitudinal distribution of Titan's haze at the Voyager epoch |
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| Authors: | A Negrão M Roos-Serote K Rages |
| Institution: | a Observatory of Paris at Meudon, 5 Place J. Janssen, 92195 Meudon, Cedex, France b Faculty of Sciences of the University of Lisbon, Lisbon, Portugal c Lisbon Astronomical Observatory, Tapada da Ajuda, 1349-018 Lisbon, Portugal d Service de Aéronomie/IPSL, University of Versailles-St-Quentin, France e Ames Research Center, Moffett Field, California, USA |
| Abstract: | We have analysed all the available high phase angle images of Titan limb taken by Voyager 1 and 2, in early 1980. For several different phase angles and wavelengths, we seek for a consistent set of haze parameters able to fit all data simultaneously. Our main purpose is to obtain an accurate estimate of the latitudinal variation of haze opacity at 200 km altitude at the time of the Voyager flyby's. We find that haze opacity at 200 km is about constant in the southern hemisphere and drops between equator and 60°N by about 30-50%, sharply increasing again beyond 60°N. The latter feature is clearly due to the north polarhood.This behaviour is opposite to total optical depth variations retrieved from IRIS observation, at the same epoch. The IRIS data refer to levels below 100 km altitude. A comparison of our results with calculations from a general circulation model, shows that (1) our results are realistic and can be considered as robust (2) the opacity variations at 200 km (this work) and at ground (IRIS data), although opposite, are not inconsistent with each other. |
| Keywords: | Titan Atmosphere Haze Voyager Imaging |
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