Jupiter has a very complex atmosphere. It is dominated by colorful bands and
turbulent swirls, as illustrated in the following two images.
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| Storms in the atmosphere of Jupiter (Ref) | Jupiter and Io with Ganymede's shadow on Jupiter (Ref) |
Zones and Belts
All that we see is the top of the atmosphere. The light bands are called zones and the darker bands are called belts. The zones tend to be white or yellow, while the belts are often some shade of reddish brown. Temperature measurements by the Pioneer spacecraft (1973) established that the temperature of the dark belts is higher than that of the light zones, implying that the former are lower in the atmosphere. Thus, the belts appear to be regions of descending gas and the zones are regions of rising gas.Each hemisphere has around 6 bands with winds blowing at very high velocities in opposite directions. This accounts for the extensive shear and turbulence at the boundaries between these regions (see the next section on the Great Red Spot). Large lightning bolts and extensive aurora have been observed in the Jovian atmosphere, as we will discuss further when we consider Jupiter's magnetic field.
The Great Red Spot
The most prominent feature is the "Great Red Spot", which may be seen on the right of the upper left image, just below the equator, and in the two images shown below. As we shall discuss in the next section, it is a kind of large and persistent storm driven by Jupiter's internal heat source.
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| Jupiter with two moons seen against its surface | Jupiter's clouds near the Great Red Spot |
The Color of the Atmosphere
The explanation for the color of Jupiter's clouds is still something of a mystery. Although there are compounds in Jupiter's atmosphere that could account for the colors if the atmosphere were warmer, they should not be the colors that are observed at the very cold temperatures in the tops of Jupiter's clouds (about -150 degrees Celsius). It has been suggested that the colors result either from colorful hydrogen compounds welling up from warmer regions, or from colorful compounds associated with trace amounts of elements like sulfur in the atmosphere. Consultation of past observations of Jupiter indicates that the clouds change their colors over time.The Galileo Probe and Orbiter
The Galileo Project is in the process of generating large amounts of new information about Jupiter and its moons. The interpretation of the information sent back by the probe that plunged into the atmosphere should yield valuable insight, as will the extended observations from the Galileo orbiter. Here is the present position and projected orbit of Galileo.
Information supplied by: http://csep10.phys.utk.edu