Jupiter's 24°N highest speed jet:: Vertical structure deduced from nonlinear simulations of a large-amplitude natural disturbance

The evolution of a large-amplitude disturbance at cloud level in Jupiter's 24 degrees N jet stream in 1990 is used to constrain the vertical structure of a realistic atmospheric model down to the 6 bar pressure level, We use the EPIC Model (Dowling et al.. 1998. The explicit planetary isentropic-coordinate (EPIC) atmospheric model, Icarus 132, 221-238) to perform long-term. three-dimensional. nonlinear simulations with a series of systematic variations in vertical structure and find that the details of the 1990 disturbance combine with the characteristics of the 24 degrees N jet, the fastest on Jupiter, to yield a tight constraint on the solution space, The most important free parameters are the vertical dependence of the zonal-wind profile, and the thermal structure, below, the Cloud tops (p = 0.7 bar) at the jet's central latitude. The temporal evolution of the disturbed cloud patterns, which spans more than 2 years. can be reproduced if the jet peak reaches similar to 180 ms(-1) at the cloud level and increases to similar to 210 ms(-1) at I bar and LIP to similar to 240 ms(-1) at 6 bar: the observations were not reproduced for other configurations, investigated. This trend is consistent with that measured by the Galileo Probe at 7 degrees N. the implication is that this jovian jet extends well below the solar radiation penetration level situated near the 2 bar level. (c) 2005 Elsevier Inc. All rights reserved.