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Kunio Sayanagi

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Postdoctoral Scholar
California Institute of Technology
1200 E. California Blvd.
Pasadena, CA 91125

Research Summary:

My main interests are in the atmospheric dynamics of gas-giant planets.  I am especially interested in the behaviors of jetstreams.  In my research, I analyze the images captured by space missions to measure the winds, and then employ numerical simulations to understand the underlying mechanisms that govern their behaviors.

Title 1: Formation and Maintanence of Jets in Gas Giant Atmospheres

Abstract 1:

Jupiter and Saturn have approximately 30 and 15 atmospheric jetstreams blowing at the cloud level.  These jetstreams' speeds and locations have undergone only minor changes since the beginning of planetary mission based measurements by the Voyager probes in 1979.  This remarkable stability is in a stark contrast to the atmospheric jetstreams on Earth, which continuously meander and change their course.  I will discuss the formation and maintenance mechanisms of the atmospheric jetstreams on Jupiter and Saturn, and compare their dynamics to the jets on Earth.

Title 2: Cassini Observations of Saturn's North Polar Hexagon

Abstract 2:

The Voyager 2 flyby of Saturn in 1981 revealed a hexagonal cloud structure around the north pole.  The hexagonal structure was hidden in the winter polar night since around 1990 and was revealed with the arrival of the Cassini orbiter to the Saturnian system in 2004.  Cassini first confirmed the continuing existence of the Hexagon in infrared wavelengths while the north pole was still in winter darkness.  Since 2008, the Hexagon region has been illuminated by sunlight, enabling observations by Cassini's high-resolution cameras in visible wavelengths and revealed its remarkable dynamic structures.  I will discuss the latest observational findings by the Cassini mission in the high-latitude regions of Saturn.



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