Abstract
We present an analysis of new cloud motion measurements in Saturn's
atmosphere from Voyager 1 and 2 images and define a nominal zonal wind
velocity vs latitude profile for the cloud top level that can be used as
reference for the upcoming Cassini mission. Improvements over previous
studies include: (i) twice the number of wind vectors used, (ii)
independent measurements of cloud tracers, (iii) extended latitudinal
coverage, (iv) strict error control and evaluation, and (v) a new zonal
averaging methodology. Mean zonal wind velocities are given for the
latitude range 81° to -71° (planetographic) in steps of 0.5°
with a gap between 0° and -10° due to ring shadowing. This
research also includes the study of the morphology and motions of cloud
systems in the equator and in the southern hemisphere which have not
been described previously. We give an ephemeris (motion equation) for
several long-lived features that could be observable if they survive
until Cassini arrives on Saturn. The long-term behavior of the zonal
wind profile is studied by comparing it with a complete set of wind
velocities compiled from historical and modern ground-based and HST
observations. Significant changes are noted in the equatorial jet
between this set and the nominal Voyager profile. We discuss in detail
the possible origin for such differences.
Original language | English |
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Pages (from-to) | 405-420 |
Number of pages | 16 |
Journal | Icarus |
Volume | 147 |
Issue number | 2 |
DOIs | |
Publication status | Published - 1 Oct 2000 |
Externally published | Yes |
All Science Journal Classification (ASJC) codes
- Astronomy and Astrophysics
- Space and Planetary Science