From Newsgroup: sci.space.news


http://www.jpl.nasa.gov/news/news.php?feature=6670

Watching Summer Clouds on Titan
Jet Propulsion Laboratory
November 4, 2016

NASA's Cassini spacecraft watched clouds of methane moving across the
far northern regions of Saturn's largest moon, Titan, on Oct. 29 and
30, 2016.

Several sets of clouds develop, move over the surface and fade during
the course of this movie sequence, which spans 11 hours, with one frame
taken every 20 minutes. Most prominent are long cloud streaks that lie
between 49 and 55 degrees north latitude. While the general region of
cloud activity is persistent over the course of the observation, individual streaks appear to develop then fade. These clouds are measured to move
at a speed of about 14 to 22 miles per hour (7 to 10 meters) per second.

There are also some small clouds over the region of small lakes farther
north, including a bright cloud between Neagh Lacus and Punga Mare, which
fade over the course of the movie. This small grouping of clouds is moving
at a speed of about 0.7 to 1.4 miles per hour (1 to 2 meters) per second.

Time-lapse movies like this allow scientists to observe the dynamics of
clouds as they develop, move over the surface and fade. A time-lapse movie
can also help to distinguish between noise in images (for example from
cosmic rays hitting the detector) and faint clouds or fog.

In 2016, Cassini has intermittently observed clouds across the northern mid-latitudes of Titan, as well as within the north polar region -- an
area known to contain numerous methane/ethane lakes and seas see PIA19657
and PIA17655. However, most of this year's observations designed for cloud monitoring have been short snapshots taken days, or weeks, apart. This observation provides Cassini's best opportunity in 2016 to study short-term cloud dynamics.

Models of Titan's climate have predicted more cloud activity during early northern summer than what Cassini has observed so far, suggesting that
the current understanding of the giant moon's changing seasons is incomplete.

The mission will continue monitoring Titan's weather around the 2017 summer solstice in Titan's northern hemisphere.

The movie was acquired using the Cassini narrow-angle camera using infrared filters to make the surface and tropospheric methane clouds visible.

The Cassini mission is a cooperative project of NASA, ESA (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. The Cassini orbiter and its two onboard cameras were designed, developed and assembled
at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colorado.

For more information about the Cassini-Huygens mission visit http://saturn.jpl.nasa.gov
and http://www.nasa.gov/cassini. The Cassini imaging team homepage is
at http://ciclops.org.

News Media Contact
Preston Dyches
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-7013
preston.dyches@jpl.nasa.gov

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