Publication Abstracts

Allison 1990

Allison, M., 1990: Planetary waves in Jupiter's equatorial atmosphere. Icarus, 83, 282-307, doi:10.1016/0019-1035(90)90069-L.

Voyager infrared, radio occultation, and imaging measurements provide a variety of observational evidence and constraints for planetary-scale waves latitudinally trapped within Jupiter's equatorial jet. The visually prominent plumes, encircling the planet at 8° north latitude, show a latitudinal organization of wavenumber n ≃ 11-13. An apparently solitary plume also appears at about 8° south along with other smaller periodic cloud features. Deviations in cloud-tracked drift speeds (including differences in mean values to the north and south of the equator) in excess of 25 m/sec may be crudely indicative of the magnitude of the associated wave phase speeds. Radio occultation retrievals of the temperature profiles at two equatorial longitudes show harmonic variation consistent with the stratospheric propagation of two components with vertical wavelengths of approximately 3 and 0.5 scale heights. These observations may be consistently interpreted in terms of specific classes of equatorially trapped wave modes. The gravest equatorial Rossby mode with an "equivalent depth" of h ≃ 2-4 km (with a stratospheric wavelength of 3-4 scale heights) represents the most consistent interpretation of the plumes. The inferred vertical eigenmode could be ducted by a deep, statically stable layer, possibly imposed by a roughly solar abundant water cloud, depending upon the actual details of the moist convection. An estimate of the relative growth rates for the near-neutral forcing of Rossby modes of the inferred equivalent depth implies a maximum for zonal wavenumber 11. The solitary plume feature to the south of the equator may be interpreted as a wavenumber 1 Rossby mode with the same vertical scale, possibly forced by the interaction between the equatorial jet and the Great Red Spot. Smaller visual features may correspond to inertia-gravity modes with vertical wavelengths comparabel to the small harmonic of the occultation profiles. Galileo orbiter and probe observations will provide an essential test of the wave analysis and substantially enhance its diagnostic utility.

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BibTeX Citation

  author={Allison, M.},
  title={Planetary waves in Jupiter's equatorial atmosphere},

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RIS Citation

ID  - al05100g
AU  - Allison, M.
PY  - 1990
TI  - Planetary waves in Jupiter's equatorial atmosphere
JA  - Icarus
VL  - 83
SP  - 282
EP  - 307
DO  - 10.1016/0019-1035(90)90069-L
ER  -

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