A Survey of Small-Scale Waves and Wave-Like Phenomena in Jupiter's
Atmosphere Detected by JunoCam
In the first 20 orbits of the Juno spacecraft around Jupiter, we have
identified a variety of wave-like features in images made by its
public-outreach camera, JunoCam. Because of Juno’s unprecedented and
repeated proximity to Jupiter’s cloud tops during its close approaches,
JunoCam has detected more wave structures than any previous surveys.
Most of the waves appear in long wave packets, oriented east-west and
populated by narrow wave crests. Spacing between crests were measured as
small as ~30 km, shorter than any previously measured.
Some waves are associated with atmospheric features, but others are not
ostensibly associated with any visible cloud phenomena and thus may be
generated by dynamical forcing below the visible cloud tops. Some waves
also appear to be converging and others appear to be overlapping,
possibly at different atmospheric levels. Another type of wave has a
series of fronts that appear to be radiating outward from the center of
a cyclone. Most of these waves appear within 5° of latitude from the
equator, but we have detected waves covering planetocentric latitudes
between 20°S and 45°N. The great majority of the waves appear in regions
associated with prograde motions of the mean zonal flow. Juno was unable
to measure the velocity of wave features to diagnose the wave types due
to its close and rapid flybys. However, both by our own upper limits on
wave motions and by analogy with previous measurements, we expect that
the waves JunoCam detected near the equator are inertia-gravity waves.