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| New observations and modelling of a QBO-like oscillation in Jupiter's stratosphere |
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| Author(s): Friedson AJ |
| Source: ICARUS Volume: 137 Issue: 1 Pages: 34-55 Published: JAN 1999 |
| Times Cited: 13 References: 47 |
| Abstract: We present a new analysis of the "quasi-quadrennial'' oscillation (QQO), a quasi-periodic oscillation of longitude-mean temperatures and winds occurring at low latitudes in Jupiter's stratosphere that may be a phenomenon closely related to Earth's quasi-biennial oscillation (Leovy et al. 1991, Nature 354, 380-382). Measurements of 7.8-mu m thermal emission from the jovian stratosphere acquired during the period 1991-1995 extend observations of this oscillation for an additional cycle beyond those presented in Orton ef al. (1991, Science 252, 537-542), showing that this similar to 4-yr-period signal has persisted for at least 15 yr. Numerical simulations of the QQO are performed to compare the brightness temperature patterns obtained to the groundbased measurements. By coupling these simulations with a radiative transfer model, we find that the amplitude of the oscillation must be significantly larger than previously estimated by Leovy et al. (1991.). Long-period, large-scale equatorial waves on Jupiter are found to be ineffective in driving a QQO that produces the observed amplitude of the brightness temperature oscillations. Simulations in which the wave driving occurs through the interaction of small-scale, short-period gravity waves with their critical levels produce a QQO whose associated brightness temperature variations are in much better agreement with the observations. The amplitude of the QQO predicted by these simulations is large, suggesting that it may have a very significant effect on Jupiter's stratospheric thermal structure at ion: latitudes, some of which may be apparent in the vertical temperature profiles measured by the Galileo Atmospheric Structure Instrument and by the Voyager 1 radio occultation experiment. (C) 1999 Academic Press. |
| Document Type: Article |
| Language: English |
| Reprint Address: Friedson, AJ (reprint author), CALTECH, Jet Prop Lab, Div Earth & Space Sci, MS 169-237, Pasadena, CA 91109 USA |
Addresses:
1. CALTECH, Jet Prop Lab, Div Earth & Space Sci, Pasadena, CA 91109 USA |
| Publisher: ACADEMIC PRESS INC, 525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA |
| Subject Category: Astronomy & Astrophysics |
| IDS Number: 162XT |
| ISSN: 0019-1035 |
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