37th DPS Meeting, 4-9 September 2005
Session 2 Huygens
Invited, Monday, September 5, 2005, 11:00am-12:30pm, Music Concert Hall

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[2.01] A Measurement of Titan's Zonal Winds by the Huygens Doppler Wind Experiment

M.K. Bird, R. Dutta-Roy, Y. Dzierma (Radioastron. Inst., Univ. Bonn, Bonn, Germany), M. Allison (Goddard Inst. for Space Studies), S.W. Asmar, W.M. Folkner, D.V. Johnston, R.A. Preston (Jet Propulsion Lab., Caltech), D.H. Atkinson (Dept. Elec. Engg., Univ. Idaho, Moscow), I.M. Avruch, L.I. Gurvits, S.V. Pogrebenko (Joint Inst. for VLBI Europe, Dwingeloo, The Netherlands), P. Edenhofer (Inst. HF-Tech., Univ. Bochum, Germany), D. Plettemeier (Elektrotech. Inst., Tech. Univ. Dresden, Germany), G.L. Tyler (Center for Radar Astron., Stanford Univ.)

The Huygens Doppler Wind Experiment was designed to determine the strength and direction of Titan's zonal winds during the probe descent. The Doppler shift of the Huygens 2040 MHz carrier signal, driven by a stable rubidium clock, was monitored at a number of large radio telescopes on Earth. A height profile of Titan winds has been derived from frequency measurements recorded at the Green Bank Telescope in West Virginia and the Parkes Radio Telescope in Australia. The zonal wind was found to be eastward (prograde) for most of the atmospheric descent, providing the first in situ confirmation of superrotation on Titan, and reached a top speed of more than 100 m/s at altitudes near 125 km. A layer of surprisingly slow wind, where the velocity decreased to near zero, was observed at altitudes in the range 60 to 100 km. Very weak westward (retrograde) winds were inferred for most of the near-surface phase of descent below 5 km.

The author(s) of this abstract have provided an email address for comments about the abstract: mbird@astro.uni-bonn.de

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Bulletin of the American Astronomical Society, 37 #3
© 2004. The American Astronomical Soceity.