My name is David Choi, and I study the weather on giant planets. When we look at
Jupiter we're seeing the top of its atmosphere and its weather layer, and its
weather layer contains a lot of interesting features such as jet streams,
vortices, storms, and these particular features called hot spots.
So hot spots are like holes in the clouds because they appear very dark when observed
in visible light, but in near infrared light they appear very bright, and this
indicates that we're seeing deeper down into warmer layers of the atmosphere. Hot
spots have been previously studied by the Galileo atmospheric probe. In 1995
the spacecraft released a probe that descended into Jupiter's atmosphere
specifically at a hot spot, and this probe made the first in situ
measurements and the only in situ measurements of Jupiter that exist today.
So it's very important to understand how hot spot meteorology works, in order to
place these in situ measurements from the Galileo probe in its proper
In 2000 the Cassini spacecraft flew past Jupiter and created a series
of still images that we compiled into time-lapse movies of Jupiter's
atmosphere. Using these movies, we observed Rossby waves that caused
north-south meanders in a jet stream south of the equator. With new movies we
instead focused on hot spots. Hot spots are unique because we believe that there
is a Rossby wave similar to what we previously detected, but instead of this
Rossby wave moving north-south, it primarily moves up and down in the
atmosphere. The downward portion of the wave pushes air down into warmer layers
of the atmosphere. This causes any clouds that are embedded within the wave to
evaporate and prevents further clouds from forming. So at any given time there
are approximately eight to ten hot spots in Jupiter's atmosphere that are spaced
roughly evenly apart from one another. We believe that each of the downward
portions of this Rossby wave corresponds to the hot spots that we see on Jupiter.
This new finding is exciting because it will allow us to re-examine the Galileo
probe data, and allow us to better understand it and better place it in the
context of Jupiter's overall global climate and atmosphere.
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