DPS Pasadena Meeting 2000, 23-27 October 2000
Session 10. Outer Planets Posters I - Atmospheric Dynamics and Clouds
Displayed, 1:00pm, Monday - 1:00pm, Friday, Highlighted Tuesday and Thursday, 3:30-6:30pm, C101-C105, C211

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[10.03] A study of the stability of Jovian winds from HST images: 1995 - 1998

E. Garcia-Melendo (E. Duran Obs. Found.), A. Sanchez-Lavega (UPV)

The resolution of the best WFPC-2 HST Jupiter images was ~200 kmpix-1, which is close to the maximum resolution obtained by the narrow angle cameras on board Voyager 1 and 2, ~160 kmpix-1. This property of the best HST Jupiter imaging spanning a whole Jovian rotation, encouraged the use of correlation techniques to obtain a series of high resolution zonal wind profiles with a velocity data scatter similar to that obtained from Voyager images. This approach provided a unique opportunity to study the Jovian winds during a time span of 4 years, which is about 12 times longer than the 4 month lapse between the two Voyager flybys in 1979, 16 years later, and before the Cassini encounter at the end of 2000. A total of six series of wind profiles from October 5, 1995 to July 16, 1998, in the 410nm, 889nm, and 953nm bands were obtained with an average velocity scatter between 5 and 6 m/s. Jovian winds were also explored up to planetographic latitudes close to +80 degrees north and -70 degrees south. Results show the presence of two previously unknown jets over +60N and at least an additional one to the south of 60S degrees latitude. Wind profiles obtained at different wavelengths were also virtually indistinguishable, suggesting a negligible influence of a possible height effect. One of the most conspicuous results is the strong general stability displayed by the wind profile during the four year span, although the jet stream at 26S showed important alterations in shape. Comparing the HST wind profiles with the Voyager 2 wind profile obtained in violet light by S. Limaye (Icarus, Vol. 65, 335, 1986), slight latitude differences up to 1.5 degrees latitude are suggested for the location of some westerly and easterly jet streams, specially in the planet's northern hemisphere. Important changes also occurred in the eastward jets at 6S and 23N degrees of latitude.

This work was supported by E. Duran Foundation and Gobierno Vasco PI 034/97.

The author(s) of this abstract have provided an email address for comments about the abstract: duranobs@astro.gea.cesca.es

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