Wind
patterns of Jupiter's equatorial region. This mosaic covers an area of 34,000
kilometers by 22,000 kilometers and was taken using the 756 nanometer (nm)
near-infrared continuum filter. The dark region near the center of the mosiac
is an equatorial 'hotspot' similar to the Galileo Probe entry site. The
near-infrared continuum filter shows the features of Jupiter's main visible
cloud deck.
Jupiter's atmospheric circulation is dominated by alternating jets of east/west
(zonal) winds. The bands have different widths and windspeeds but have remained
constant as long as telescopes and spacecraft have measured them. The top
half of these mosaics lies within Jupiter's North Equatorial Belt, a westward
(left) current. The bottom half shows part of the Equatorial Zone, a fast
moving eastward current. The clouds near the hotspot are the fastest moving
features in these mosaics, moving at about 100 meters per second, or 224
miles per hour. |
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Superimposed
on the zonal wind currents is the Jovian 'weather'. The arrows show the
winds measured by an observer moving eastward (right) at the speed of the
hotspot. (The observer's perspective is that the hotspot is 'still' while
the rest of the planet moves around it.) Clouds south of the hotspot appear
to be moving towards it, as seen in the flow aligned with cloud streaks
to the southwest and in the clockwise flow to the southeast. Interestingly,
there is little cloud motion away from the hotspot in any direction. This
is consistent with the idea that dry air is converging over this region
and sinking, maintaining the cloud-free nature of the hotspot.
North is at the top. The mosaic covers latitudes 1 to 19 degrees and is
centered at longitude 336 degrees West. The smallest resolved features are
tens of kilometers in size. These images were taken on December 17, 1996,
at a range of 1.5 million kilometers by the Solid State Imaging system aboard
NASA's Galileo spacecraft. |
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