Assigned ID: 235 ----- Attempting Submission 1 (Thu Feb 23 22:49:51 GMT 2012) ----- I propose to use most of the HST images of Uranus to characterize its atmosphere as function of wavelength, latitude, longitude, and time. The HST data set of Uranus at CCD wavelengths is unique since no other data set of Uranus has a similar combination of spectral coverage, spatial resolution, and temporal coverage. Among 700+ planets, Uranus is the planet best observed by HST. This proposal follows program AR 11259, which analyzed 620 HST images of Neptune and revealed discoveries about Neptune's atmosphere and its interior detailed in two papers, suggesting the revolutionary idea that some features observed at visible wavelengths are connected to motions in the deep interior. Data from each latitude in each image will create some 100,000 center-to-limb curves, orders of magnitude more than all previous investigations combined, and information about ~100 discrete features. These data will be analyzed by statistical methods and the principal component analysis. Results will uncover the interconnection between latitudinal variations, temporal changes on various time scales, and Uranus' vertical structure from filters probing different altitudes. Nothing remotely similar has ever been done with the HST data set of Uranus. The data set covers 18 years and includes the equinox of Uranus when fast changes occurred on Uranus. The extreme seasons of Uranus offer a unique case to study seasonal change on an ice giant. No other planet among hundreds of ice giants has a similar seasonal record. Results from this work will test our understanding of all ice giants. Acquiring 1000 images of Uranus was a major accomplishment of HST deserving a comprehensive study. SOLAR SYSTEM 12 Medium false 0.0 0.0 false false false false SUPPORTED