Enroute to Pluto, the New Horizons encounter with Jupiter in January-March 2007 produced stunning new views and revelations about the planet's dynamic meteorology. The sharpest multi-spectral global views ever obtained in the near-infrared revealed spectroscopically-identifiable ammonia clouds (SIACs) near 30 degrees south latitude, the first such detection of discrete ammonia clouds southward of the Great Red Spot. Movies of these clouds obtained over four jovian days revealed their rapid development and dissipation, consistent with a lifetime for SIACs of a few days. Winds within the Little Red Spot (LRS) measured by the LORRI telescopic imager were found to be comparable to those previously measured for the Great Red Spot. The turbulent wake region northwest of the Great Red Spot, observed repeatedly by the LEISA near-infrared spectral mapper, was found to be atypically quiescent, absent the dynamic cloud systems observed repeatedly over the previous 28 years by the Voyager, Galileo, and Cassini spacecraft. Compared to previous spacecraft views, a significant thinning of clouds is reported for the southern half of the Equatorial Region. Mesoscale wave structures were observed by LORRI at low latitudes at a spatial resolution of 11 km, yielding a longitudinal wavelength of 300 km. Temporal coverage by MVIC resulted in the first measurement of phase velocity for such waves: 100 m/s. Lightning was discovered at both poles, the first such optical detection of polar lightning for any planet beyond the Earth. The mean polar lightning radiative flux is found to be comparable to that previously reported for the mid-latitudes and significantly greater than reported for the equatorial region, consistent with internal heating being the main driver of convection on Jupiter.
AAS/Division for Planetary Sciences Meeting Abstracts #39
- Pub Date:
- October 2007