Jets on the Giant Planets

University Of Arizona, Tucson AZ

Investigators

Abstract

AST-0206269 Showman Observations from the Pioneer, Voyager, and Galileo spacecraft as well as ground-based measurements beginning in the 1800's indicate that the four giant planets in our solar system, Jupiter, Saturn, Uranus, and Neptune, have strong east-west jets in their atmospheres. The jets take different forms on each planet; Jupiter and Saturn have about twenty jets each (ten eastward and ten westward), whereas Uranus and Neptune have only about three jets each. The jets are correlated with spatial variations in the temperature and cloud abundance, suggesting that the full problem is a coupled one involving all the dynamical variables. The question of what causes these jets is one of the most important unsolved problems in planetary atmospheres. Dr. Adam Showman of the University of Arizona will investigate the dynamics and formation processes of the giant-planet jets using a fully nonlinear numerical model of atmospheric motion. Two distinct, yet related, numerical investigations will be conducted. Both are aimed at elucidating the role of small-scale convection in pumping the jets. The first problem uses a realistic parameterization of the convection and will focus predominantly on elucidating the dynamics near the cloud level. The second problem adopts a simpler representation of the convective forcing and investigates whether extremely deep jets can be driven from the upper regions where the moist convection is expected to occur. These studies are the first fully-nonlinear numerical simulations of Jupiter's cloud layer that address the problem of Jovian jet formation using a model with many vertical grid points. As a result, they will be groundbreaking in their ability to address the vertical structure that results from plausible jet-formation processes. The research will use established numerical codes that Dr. Showman is experienced in using. ***