  An essential component of planetary climatology is knowledge of the
tropospheric temperature field and its variability. Previous studies of Jupiter
hinted at periodic behavior that was non-seasonal, as well as dynamical
relationships between tropospheric and stratospheric temperatures. However,
these observations were made over time frames shorter than Jupiter's orbit or
they used sparse sampling. We derived upper-tropospheric (300-mbar)
temperatures over 40 years, extending those studies to cover several orbits of
Jupiter, revealing unexpected results. Periodicities of 4, 7 8-9 and 10-14
years were discovered that involved different latitude bands and seem
disconnected from seasonal changes in solar heating. Anti-correlations of
variability in opposite hemispheres were particularly striking at 16, 22 and 30
degrees from the equator. Equatorial temperature variations are also
anticorrelated with those 60-70 km above. Such behavior suggests a top-down
control of equatorial tropospheric temperatures from stratospheric dynamics.
Realistic future global climate models must address the origins of these
variations in preparation for their extension to a wider array of gas-giant
exoplanets.
