The intensity variation of [SIII> 9531 A line emission from the hot plasma torus of Jupiter was measured from Kitt Peak National Observatory during April 1982 using a scanning Fabry-Perot spectrometer with a field of view 2 RJ in diameter centered at 6 RJ on the centrifugal equator. During the observational period, which covered 43 rotations of Jupiter, the intensities showed a periodic variation consistent with a zone of enhanced emission approximately 90¿ in longitude rotating with a period of 10.2 hours, or 2.8% longer than Jupiter's rotational period.