JOVIAN SYSTEM DATA ANALYSIS PROGRAM PROPOSAL SUMMARY

A two-year program is proposed which includes a variety of tasks related to both the satellites and atmosphere of Jupiter. The projects use data primarily from the Near Infrared Mapping Spectrometer (NIMS), but we include important collaborative efforts that combine NIMS data with multi-spectral images from the Solid State Imaging Experiment (SSI). Satellite Science: The composition of Io's surface will be studied by mapping a broad .0 to 1.6 micron feature observed by NIMS and combining those spectra with SSI multi-color data; this is a collaborative program to search for silicates on Io. We will also map sulfur dioxide and unidentified species on Io, and search for hydrogen sulfide features. Two studies of Europa's surface composition will be performed. The first is mapping the distribution of hydrogen peroxide on Europa's surface together with investigation of the formation and destruction mechanisms of this surface molecule. The second activity will explore alternative explanations, involving silicates, to the recent suggestion of hydrated salts on Europa. Vertical structure (layering) of the surfaces of the icy moons will be investigated using spectra obtained at multiple angles. In a related task, we will employ SSI multi-spectral imagery to extrapolate the NIMS spectra to finer spatial scales, obtaining end-member spectra and solar energy absorption rates. A search for airglow and luminescence from the satellites will be conducted. The satellite science costs for the two years are $76 K and $ 94 K. Jovian Atmosphere Science: We propose to use more than 100 "real-time" spectra, along with NIMS multi-wavelength images, to study atmospheric dynamical processes. In particular, we will investigate the vertical profiles and spatial variations of the volatiles ammonia and water. Ammonia will be studied over an extended altitude range (0.5 to 6 bars) and the variations compared to corresponding cloud changes and deep-atmosphere water vapor variations. Convection processes in the interior will also be examined through determination of the latitudinal dependence of the phosphine profile in the 2 to 8 bar region, below the photochemical regime. The data for this investigation are 5-micron spectra obtained at high latitudinal resolution along a meridian. Finally, we will investigate the magnetic field geometry and altitude of the Jovian infrared aurora observed by NIMS. The atmospheric science costs are $ 92 K and $ 98 K for the proposed two years.