Hi all,

Here are two recent images of Saturn obtained with the Hubble Space
Telescope (wavelength 814 nm) that shows the series of small dark spots
and one of accompanying sporadic the bright spots at mid-temperate
southern latitudes. The bright spot in the HST image is that captured by
Peach on Dec 18 and by Grafton on Dec 29. The bright spot imaged by
Grafton on Dec 22 was not captured on our most recent HST images (14-17
Dec), so it was a new bright spot that merits to imaged.

 A second large feature in the Equator, as those reported by Don Parker,
can also be seen close to the West limb -right- on 16 Dec, and to the East
limb -left- on 17 Dec.

According to our studies and models, these spots are most probably
storms triggered by moist convection (most probably ammonia). Other
greater storms (as the equatorial events in 1990 and 1994-1997) are also
of convective origin but the "fuel" is most probably water. Perhaps they
are a response to the seasonal insolation cycle in Saturn's atmosphere
(current sub-solar latitude is about 30 deg South) but this is not
evident in view of Saturn's slow thermal response to heat variations. What
we now is that this kind of mid-latitude storms were also observed by the
Voyager 1 and 2 spacecrafts about 20 years ago at similar latitudes in the
northern hemisphere (when sub-solar latitude was about 8 deg North). In
both cases (North and South) the wind profile is very similar at these
latitudes so the structure of the zonal wind profile plays a role in
producing these storms.

Happy new year!!

Agustin
(for the IOPW)
------------------------------------------
Prof. Agustin Sanchez Lavega
Dpto. Fisica Aplicada I
Escuela Superior de Ingenieros
Universidad del Pais Vasco
Alda. Urquijo s/n
48013 BILBAO (Spain)
Tfno.: 946014255
Fax: 946014178
e-mail: wupsalaa@bi.ehu.es