Published by the American Geological Institute
News and Trends in the Geosciences
April 2000

News Notes

Galileo reports on the weather ... on Jupiter

Enormous storms, some larger than Earth, continuously ravage Jupiter's surface with lightning bolts three times the size of terrestrial "superbolts." New data from the NASA Galileo probe suggest that unlike Earth, where the convection of solar heat drives stormy weather, the power behind Jupiter’s storms may come from within. In studies published in the Feb. 10 Nature and December 1999 Icarus, researchers suggest that jovian storms are driven not by the sun but by the release of heat from Jupiter's hydrogen core.

The presence of storms, and even lightning, on Jupiter has been known since the Voyager missions of the late 1970s. However, the new data are more complete and reveal previously unobserved details of cloud structure and dynamics.

The researchers — from Caltech, Cornell, UCLA, NASA’s Jet Propulsion Laboratory and Ames Research Center, ITRES Research, and the Galileo team — deduced from Galileo’s images that storms on Jupiter produce both water condensation and lightning. In comparing this information to other parameters, such as lightning depth, the research team concluded that convection of internal heat produces the storms.
Above: Galileo mapped these images of two jovian storms.

Top: Superimposing images with different wavelengths and ability to absorb methane created the top color image.  The different colors represent different depths (or pressures) sunlight can penetrate the atmosphere: blue (about 0.5 bar), green (3 bar) and red (deeper than 3 bar).

Middle: Blue lightning strikes, photographed from nighttime images of the storm, are overlaid on a black-and-white image of the storm during the day.

Bottom: Wind vectors overlaid on the bottom image show counterclockwise rotation just east of the storm at 265 degrees west longitude. This anticyclonic vorticity contrasts with a strong cyclonic shear at 269 degrees west longitude, slightly northwest of the storm.

Image courtesy of NASA/JPL/Cornell

Josh Chamot
Geotimes contributing writer