Stability of Jets on Jupiter and Saturn

Cornell University, Ithaca NY

Investigators

Abstract

AST 0306955 Gierasch The well-known atmospheric jets on Jupiter and Saturn have such large amplitudes that by conventional criteria for two dimensional flow they should be unstable. This is particularly surprising because two dimensional flow models do well in other respects in reproducing alternating jets, large vortices and other features of the planetary flows. With this award, Dr. Peter Gierasch, of Cornell University, will investigate a hypothesis about the vertical structure of these flows in an effort to resolve this problem. Preliminary results suggest that a deep meteorological layer with small stratification has stability properties in good agreement with observations. Although deep, the layer is still shallow when compared with the planetary radius. The preliminary work shows that jets can be about three times as strong as under the conventional instability criterion, and in addition, westerly (eastward) jets are more stable than easterly jets, in agreement with the much stronger westerlies that are observed on the planets. Jupiter and Saturn are well-known objects that intrigue the general public. This project addresses a major, easily understood question about these planets. Successful results will make it easier to explain Jupiter and Saturn to students, and will make these planets even more valuable as comparative examples in earth and planetary science. Results of this research, if successful, will receive wide dissemination during the 2004-2008 time period when the NASA Cassini spacecraft will be at Saturn, pushing Saturn forward into the news. More locally, students at Cornell will be directly will be directly involved in the research, and results will be incorporated into teaching programs in both the Astronomy Department and the Department of Earth and Atmospheric Sciences at Cornell. ***