HR: 0800h
AN: P11A-0091    [Abstracts]
TI: Deep Jets on Gas Giant Planets
AU: * Lian, Y
EM: lian@lpl.arizona.edu
AF: The University of Arizona, Lunar & Planetary Lab 1629 E. University Blvd., Tucson, AZ 85721 United States
AU: Showman, A P
EM: showman@lpl.arizona.edu
AF: The University of Arizona, Lunar & Planetary Lab 1629 E. University Blvd., Tucson, AZ 85721 United States
AU: Gierasch, P J
EM: gierasch@astro.cornell.edu
AF: Cornell University, 318 Space Sciences Building, Ithaca, NY 14853 United States
AB: Galileo probe measurement on Jupiter in 1996 indicated the jets on Jupiter reach the depth of at least 22 bars. Some people interpreted this as an evidence that Jupiter's wind is forced in the deep atmosphere; however, it neglects the possibility that a deep jet may result from a shallow forcing. Our project investigates whether a deep jet can be generated by a shallow forcing, i.e. solar radiation. To test this idea, we use a global circulation model(GCM) developed by MITgcm group. All our simulations are initialized with an atmosphere at rest. We apply Newtonian cooling scheme to numerical models and vary its radiative equilibrium profiles to study the wind's response. The early stage of our simulations shows that a shallow temperature forcing confined to 2~3 bar level produces multiple jets above troposphere; prolonged simulations show deep barotropic winds start to form and develop. These barotropic winds, which have speeds comparable to the wind at the top of atmosphere, can reach 25 bar and even 100 bar levels. The simulation results controvert the common sense that shallow forcing only produces shallow jets. Meridional overturning circulation plays an important role to drive deep winds in our simulations. Equatorial superrotation is also produced under certain conditions.
DE: 5704 Atmospheres (0343, 1060)
SC: Planetary Sciences [P]
MN: Fall Meeting 2005