Characterization of zonal winds in the stratosphere of Titan
Publication date: 15 December 2005
Authors: Luz, D., et al.
Journal: Icarus
Volume: 179
Issue: 2
Page: 497-510
Year: 2005
Copyright: Elsevier
Titan has been observed with UVES, the UV-Visual Echelle Spectrograph at the Very Large Telescope, with the aim of characterizing the zonal wind flow. We use a retrieval scheme originally developed for absolute stellar accelerometry [Connes, P., 1985. Astrophys. Space Sci., 110, 211-255] to extract the velocity signal by simultaneously taking into account all the lines present in the spectrum. The method allows to measure the Doppler shift induced at a given point by the zonal wind flow, with high precision. The short-wavelength channel (420-520 nm) probes one scale height higher than the long-wavelength one (520-620 nm), and we observe statistically significant evidence for stronger winds at higher altitudes. The results show a high dispersion. Globally, we detect prograde zonal winds, with lower limits of 62 and 50 ms-1 at the regions centered at 200 and 170 km altitude, but approximately a quarter of the measurements indicates null or retrograde winds.
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