Rapid Response to Anomalous Activity in Jupiter's Atmosphere

The well-documented record of aperiodic disturbances within Jupiter's atmosphere reveals that their onset is marked by an intensely white cloud that expands and interacts with the local winds. These storms are associated with large-scale variability of the Jovian cloud deck, and could play a significant role in the heat balance of the atmosphere. Although the Galileo mission will be active during Cycle 6, it cannot readily respond to the events and will be on the dark side of the planet most of the time. Disturbances include plume-like systems at 23 deg. N and 7 deg. N planetographic latitude near the peak of eastward jets and active convective sites near +/-15 deg. latitude in regions of cyclonic shear {descending flow}. Center-to-limb observations reveal the initial white cloud is bright near the limb, indicating penetration to high altitude and possible tropospheric heating and interruption of cold trapping of ammonia. Horizontal rates of expansion are on the order of 10-20 m s^-1 allowing the initial storm site to be identifiable for 2-3 weeks. Longitudinal positions will be obtained by groundbased observers using visual timings of central meridian crossings and analysis of CCD images. They will report to Beebe who will determine the magnitude of the disturbance and, if appropriate, alert Noll to request a Target of Opportunity. Observations with the STIS and WFPC2 will quantify the extent of ammonia upwelling, delineate interaction with the local wind field, and provide information on vertical structure of the disturbance.