Dynamical implications of Jupiter's tropospheric ammonia abundance

Adam P. Showman, Imke de Pater

Research output: Contribution to journalArticle

41 Scopus citations

Abstract

Groundbased radio observations indicate that Jupiter's ammonia is globally depleted from 0.6 bars to at least 4-6 bars relative to the deep abundance of ∼ 3 times solar, a fact that has so far defied explanation. The observations also indicate that (i) the depletion is greater in belts than zones, and (ii) the greatest depletion occurs within Jupiter's local 5-μm hot spots, which have recently been detected at radio wavelengths. Here, we first show that both the global depletion and its belt-zone variation can be explained by a simple model for the interaction of moist convection with Jupiter's cloud-layer circulation. If the global depletion is dynamical in origin, then important endmember models for the belt-zone circulation can be ruled out. Next, we show that the radio observations of Jupiter's 5-μm hot spots imply that the equatorial wave inferred to cause hot spots induces vertical parcel oscillation of a factor of ∼2 in pressure near the 2-bar level, which places important constraints on hot-spot dynamics. Finally, using spatially resolved radio maps, we demonstrate that low-latitude features exceeding ∼4000 km diameter, such as the equatorial plumes and large vortices, are also depleted in ammonia from 0.6 bars to at least 2 bars relative to the deep abundance of 3 times solar. If any low-latitude features exist that contain 3-times-solar ammonia up to the 0.6-bar ammonia condensation level, they must have diameters less than ∼ 4000 km.

Original languageEnglish (US)
Pages (from-to)192-204
Number of pages13
JournalIcarus
Volume174
Issue number1
DOIs
StatePublished - Mar 1 2005

Keywords

  • Atmospheres, composition
  • Atmospheres, dynamics
  • Jupiter, atmosphere
  • Radio observations

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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