FIGURE 1. Representative thermal images of Saturn showing two phases of the oscillation.
From the following article:
Semi-annual oscillations in Saturn's low-latitude stratospheric temperatures
Glenn S. Orton, Padma A. Yanamandra-Fisher, Brendan M. Fisher, A. James Friedson, Paul D. Parrish, Jesse F. Nelson, Amber Swenson Bauermeister, Leigh Fletcher, Daniel Y. Gezari, Frank Varosi, Alan T. Tokunaga, John Caldwell, Kevin H. Baines, Joseph L. Hora, Michael E. Ressler, Takuya Fujiyoshi, Tetsuharu Fuse, Hagop Hagopian, Terry Z. Martin, Jay T. Bergstralh, Carly Howett, William F. Hoffmann, Lynne K. Deutsch, Jeffrey E. Van Cleve, Eldar Noe, Joseph D. Adams, Marc Kassis & Eric Tollestrup
Nature 453, 196-199(8 May 2008)
doi:10.1038/nature06897
Images showing 7.8-
m methane emission from Saturn's stratosphere taken at the IRTF, illustrating the alternating amplitudes of low-latitude temperatures in the 20-mbar altitude range between the equator and latitude 15° S. At this wavelength, emission from Saturn's rings is lower than that from the planet, and their primary effect is to obscure thermal emission from the atmosphere. These images demonstrate Saturn's appearance during a relative minimum of equatorial temperatures (1997) and during a relative maximum of equatorial temperatures (2006). A similar equatorial brightening was noted in comparing IRTF images from 1989 with low equatorial temperatures derived from the Voyager-1 Infrared Radiometer Interferometer Spectrometer experiment8. We note that the warm south pole in May 2006 is driven by seasonal variability10.