The Titanian Seasons Turn, Turn, Turn

MEDIA RELATIONS OFFICE
JET PROPULSION LABORATORY
CALIFORNIA INSTITUTE OF TECHNOLOGY
NATIONAL AERONAUTICS AND SPACE ADMINISTRATION
PASADENA, CALIF. 91109 PHONE 818-354-5011
http://www.jpl.nasa.gov

Jia-Rui C. Cook 818-354-0850
Jet Propulsion Laboratory, Pasadena, Calif.
jccook@jpl.nasa.gov

Joe Mason 720-974-5859
Space Science Institute, Boulder, Colo.
media@ciclops.org

News release: 2012-200 July 10, 2012

The Titanian Seasons Turn, Turn, Turn

The full version of this story with accompanying images is at:
http://www.jpl.nasa.gov/news/news.cfm?release=2012-200&cid=release_2012-200

PASADENA, Calif. – Images from NASA's Cassini spacecraft show a concentration of
high-altitude haze and a vortex materializing at the south pole of Saturn's moon Titan,
signs that the seasons are turning on Saturn's largest moon.

"The structure inside the vortex is reminiscent of the open cellular convection that is
often seen over Earth's oceans," said Tony Del Genio, a Cassini team member at NASA's
Goddard Institute for Space Studies, N.Y. "But unlike on Earth, where such layers are
just above the surface, this one is at very high altitude, maybe a response of Titan's
stratosphere to seasonal cooling as southern winter approaches. But so soon in the game,
we're not sure."

Cassini first saw a "hood" of high-altitude haze and a vortex, which is a mass of swirling
gas around the pole in the moon's atmosphere, at Titan's north pole when the spacecraft
first arrived in the Saturn system in 2004. At the time, it was northern winter. Multiple
instruments have been keeping an eye on the Titan atmosphere above the south pole for
signs of the coming southern winter.

While the northern hood has remained, the circulation in the upper atmosphere has been
moving from the illuminated north pole to the cooling south pole. This movement
appears to be causing downwellings over the south pole and the formation of high-
altitude haze and a vortex.

Cassini's visible light cameras saw the first signs of hazes starting to concentrate over
Titan's south pole in March, and the spacecraft's visual and infrared mapping
spectrometer (VIMS) obtained false-color images on May 22 and June 7.

"VIMS has seen a concentration of aerosols forming about 200 miles [300 kilometers]
above the surface of Titan's south pole," said Christophe Sotin, a VIMS team member at
NASA's Jet Propulsion Laboratory, Pasadena, Calif. "We've never seen aerosols here at
this level before, so we know this is something new."

During a June 27 distant flyby, Cassini's imaging cameras captured a crow's-eye view of
the south polar vortex in visible light. These new images show this detached, high-
altitude haze layer in stunning new detail.

"Future observations of this feature will provide good tests of dynamical models of the
Titan circulation, chemistry, cloud and aerosol processes in the upper atmosphere," said
Bob West, deputy imaging team lead at JPL.

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 Cassini-Huygens mission
for NASA's Science Mission Directorate, Washington. The Cassini orbiter and its two
onboard cameras were designed, developed and assembled at JPL. The imaging team is
based at the Space Science Institute in Boulder, Colo.

The new images are available online at:
http://www.nasa.gov/mission_pages/cassini/whycassini/cassini20120710.html

For more information about the mission, visit: http://www.nasa.gov/cassini ,
http://saturn.jpl.nasa.gov , and http://www.ciclops.org .

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