These two images of Saturn show the entire south polar region, not just
the little area around the core of the hurricane-like vortex. Earth-like
storm patterns seem to be powering this vortex.
These images were taken in the near-infrared on May 11, 2007, from a
distance of 416,000 kilometers (258,500 miles), and with a phase angle of
36 degrees.
From this distance, the resolution is 208 kilometers (128 miles) per
pixel. The lower image represents 5.04 microns, a near-infrared wavelength
some seven times the reddest wavelength visible to the human eye. At this
wavelength, the planet's own heat produces an internal glow against which
clouds deep within Saturn are seen in silhouette. Thus, dark areas
represent thick clouds while bright areas represent clearings in the
clouds.
The upper image shows the polar region in false color, with red, green,
and blue depicting the appearance of the pole in three different
near-infrared colors. Here, red depicts the 5.04 micron image shown in the
black and white image above. Green and blue show the polar region, as seen
in reflected sunlight at 3.08 and 4.08 micron wavelengths. The aqua color
produced by green and blue light together show bright hazes and clouds in
the upper atmosphere away from the pole; the lack of an aqua color
component over the pole reveals a surprising dearth of upper-level bright
hazes and clouds at high latitudes poleward of 73 degrees latitude,
perhaps indicative of a general downwelling, heating, and sublimation into
gas vapor of aerosol particles there. This clearing of upper-level hazes
and clouds then allows—at other wavelengths not depicted here—
unusually clear sunlit views of the deep atmosphere of Saturn near the
1-bar level, much deeper than typically seen elsewhere on the planet.
Due to the lack of bright polar hazes, the pole itself shows up only in
reddish hues in this color composite. These red hues depict the
near-infrared warm glow of Saturn's interior heat diffusing upward through
the clouds, thus revealing clouds at much deeper levels than what can be
seen in reflected sunlight. Here, the brightest red coloring indicates
clearings between low-lying clouds. These clearings extend downward from
just below the haze layer down to about the 5-bar level some 125
kilometers (78 miles) below the upper-level hazes. The eye of the polar
vortex is bright, showing that it is nearly cloud free. Dark spots
throughout the region reveal the presence of thick convective clouds
lurking in the depths of Saturn in the 2 to 5-bar region, about 50 to 125
kilometers (30-80 miles) underneath the hazes. At the edge of the polar
region, where the greenish-blue tint of the upper hazes begins, a large
ring of thick clouds can be seen in silhouette encircling the planet. Fine
strands of streaky cloud material can be seen spiraling into this ring,
indicating north/south motions in the planet's deep, dynamic atmosphere.
The Cassini-Huygens mission is a cooperative project of NASA, the European
Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory,
a division of the California Institute of Technology in Pasadena, manages
the mission for NASA's Science Mission Directorate, Washington, D.C. The
Cassini orbiter was designed, developed and assembled at JPL. The Visual
and Infrared Mapping Spectrometer team is based at the University of
Arizona.
For more information about the Cassini-Huygens mission visit
http://saturn.jpl.nasa.gov/home/index.cfm. The visual and infrared mapping
spectrometer team homepage is at http://wwwvims.lpl.arizona.edu.