JOVIAN SYSTEM DATA ANALYSIS PROGRAM PROPOSAL SUMMARY

We propose to determine the optical and microphysical properties and the vertical distributions of hazes and clouds within the most prominent meteorological systems on Jupiter. We also propose to determine the spatial distributions of the condensible gases ammonia and water within and and around these features, and the distribution of phosphine, a disequilibrium molecular tracer of vertical transport from the deep atmosphere. These results will be used as inputs to a microphysical model to aid in the assessment of the dynamical nature of Jupiter's meteorology, and to constrain the role vertical advection plays in determining Jupiter's meteorology, especially the role of upwelling convective motions from the deep atmosphere near 1000 bars. Our analysis utilizes the salient attributes of the Galileo Mission to achieve the most detailed knowledge of Jupiter's three-dimensional cloud structure and distribution of dynamically- important trace gases yet obtained. This mission is remarkable for the breadth and depth of observations acquired of specific meteorological features, at the expense of a large fraction of downlink bits available (i.e., more than half of the bits allocated for atmospheric science for both Galileo/SSI and Galileo/NIMS). In this proposal, we will fully analyze these hard-won SSI and NIMS datasets, augmented by supporting high-quality imagery from HST/WFPC and HST/NICMOS. Specific features to be examined include the Great Red Spot, a White Oval, several equatorial plume features, dark features in the Equatorial Belt, and the North Tropical and South Tropical Zones (Equatorial hot spots are covered under the related proposal of Friedson). A combined analysis of the full range of contemporaneous datasets - remarkable for their wide spectral coverage (from 0.2 to 5.2 microns), for their broad sampling of a variety of opacities from atmospheric gases and particles (extending over five orders of magnitude in atmospheric opacity), and for their broad range of sampled lighting/viewing geometries (from near zero to 160 degrees phase angle) - will enable the determination of a plethora of cloud attributes, including vertical placement, wavelength-dependent opacities, and the single-scattering albedoes of constituent aerosols. Galileo's unique set of multi-wavelength multi-phase-angle observations will be analyzed to determine aerosol phase functions from 0.7 to 2.7 microns, thus placing significant constraints on particle size, shape, and composition. Utilizing this size and shape information together with the aerosol opacity information, the mass column abundances of tropospheric condensate clouds and overlying stratospheric hazes will be determined. The vapor abundances of ammonia, water, and phosphine and their spatial variability will then be determined from their respective relevant absorption features utilizing the derived aerosol structure. Microphysical models utilizing the observed particle size, number density, and ammonia humidity will be used to determine particle lifetimes, aerosol growth rates due to coagulation and condensation, and the overall evolution of clouds. These results in turn will be used to determine the role advection - particularly convection from the deep interior - plays in generating the major meteorological systems of Jupiter. This proposal combines the diverse expertise of a number of experienced atmospheric scientists especially knowledgeable about the instruments and observations of the Galileo Mission, including three Galileo Co-Investigators and the Principal Investigator of NIMS. Additional HST WFPC and NICMOS expertise comes from Collaborator Amy Simon, who has played a key role in the acquisition and analysis of HST imagery acquired in support of Galileo Jupiter observations. This proposal synergistically supports and is supported by several related JSDAP efforts being proposed by the Co-Investigators, including (1) Dr Robert W. Carlson's effort to analyze complete NIMS spectra of a number of spatially-discrete points acquired across the disk to determine additional constraints on the spatial distribution of phosphine, ammonia, and water; (2) Dr. Andrew J. Friedson's effort to understand jovian hotspots from NIMS, SSI, and PPR data; (3) Dr. Robert West's effort to understand polar chemistry, dynamics, and structure, and (4) Dr. Glenn. S. Orton's effort to analyze Jupiter's thermal structure and dynamical constraints as revealed by PPR. Together, these ensemble of tasks fully plumb the atmospheric dataset acquired at such great expense by Galileo, yielding new insights into Jupiter's meteorology, chemistry, and dynamics.