Program: GS-2007B-Q-229

We propose to measure the physical and chemical state of regions of Jupiter which underwent major changes in visual appearance since our February T-Recs observations. The southern half of the North Temperate Belt (NTBs) dramatically darkened, and the dark southern half of the South Equatorial Belt (SEBs) brightened, both changes are associated with rare events known as "global upheavals". We propose to re-map the NTBs and SEBs as early as possible, to detemine changes of temperature, the opacity of an NH3 cloud, and the abundances of NH3, PH3 and para-H2 gases. The observations will supplement cloud color and horizontal wind measurements from HST WFPC images on June 5. These measurments will discriminate between models of the cloud brightening as being the result of (i) massive particulate displacements, (ii) temperature-related phase changes, or vertical motions of condensible ammonia gas. The picture which emerges from these observations will havebroad implications for our understanding of the stability of winds in Jupiter.