On the water abundance in the atmosphere of Jupiter

In this paper, we attempt to place constraints on the possible global abundance of water and the average vertical cloud structure in the atmosphere of Jupiter. Based on the analysis of the Galileo Near-Infrared Mapping Spectrometer data, we 5nd that in the atmosphere of Jupiter down to 6–8 bar, particularly in the North Equatorial Belt (NEB) region, the overall O/H ratio is compatible with one or more times the solar value of this ratio. We also 5nd that if water clouds form at the levels where they are expected from thermochemical equilibrium calculations for a given deep O/H ratio, then subsolar values of the O/H ratio cannot be reconciled with the analyzed data. However, these results are dependent on the model atmosphere, in particular the detailed vertical distribution of cloud opacity. Therefore, they should be considered with care, until new observations on the vertical cloud structure become available. The water vapor mixing ratio in the NEB displays large spatial variations. The same set of data yield subsaturated mixing ratios of ammonia to atmospheric levels of about 4 bar. This depletion of ammonia to great depths, as seen by the Galileo Probe in the hot spot where it entered, appears to be a common phenomenon in the entire NEB. ? 2003 Elsevier Ltd. All rights reserved.

[1]  Frank S. Milos,et al.  Structure of the Atmosphere of Jupiter: Galileo Probe Measurements , 1996, Science.

[2]  T. Encrenaz,et al.  Analysis of Jupiter north equatorial belt hot spots in the 4–5 μm range from Galileo/near‐infrared mapping spectrometer observations: Measurements of cloud opacity, water, and ammonia , 1998 .

[3]  JOHN S. Lewis,et al.  Atmospheric and cloud structures of the Jovian planets , 1973 .

[4]  Sushil K. Atreya,et al.  Book-Review - Atmospheres and Ionospheres of the Outer Planets and Their Satellites , 1986 .

[5]  P. Gierasch,et al.  Infrared Observations of the Jovian System from Voyager 1 , 1979, Science.

[6]  M. Lemmon,et al.  Solar and Thermal Radiation in Jupiter's Atmosphere: Initial Results of the Galileo Probe Net Flux Radiometer , 1996, Science.

[7]  T. Encrenaz,et al.  The abundance of water on Jupiter from the voyager IRIS data at 5 μm , 1982 .

[8]  Michael H. Wong,et al.  Composition and origin of the atmosphere of Jupiter—an update, and implications for the extrasolar giant planets , 2003 .

[9]  W. Folkner,et al.  Ammonia abundance in Jupiter's atmosphere derived from the attenuation of the Galileo probe's radio signal , 1998 .

[10]  Ashwin R. Vasavada,et al.  Galileo Images of Lightning on Jupiter , 1999 .

[11]  N. Grevesse,et al.  Abundances of the elements: Meteoritic and solar , 1989 .

[12]  Gordon L. Bjoraker,et al.  The abundance and distribution of water vapor in Jupiter's atmosphere , 1986 .

[13]  S. B. Calcutt,et al.  Atmospheric Composition and Cloud Structure in Jovian 5-μm Hotspots from Analysis of Galileo NIMS Measurements , 2001 .

[14]  P. Gierasch,et al.  A Detection of Water Ice on Jupiter with Voyager IRIS , 2000 .

[15]  T. Encrenaz,et al.  A comparison of the atmospheres of Jupiter and Saturn: deep atmospheric composition, cloud structure, vertical mixing, and origin. , 1999, Planetary and space science.

[16]  G. Orton,et al.  A Dynamical Model of Jupiter's 5-Micron Hot Spots , 1999 .

[17]  G. Orton,et al.  The clouds of Jupiter: Results of the Galileo Jupiter Mission Probe Nephelometer Experiment , 1998 .

[18]  T. Dowling,et al.  Nonlinear simulations of Jupiter's 5-micron hot spots. , 2000, Science.

[19]  M. Lemmon,et al.  Galileo probe measurements of thermal and solar radiation fluxes in the Jovian atmosphere , 1998 .

[20]  B. Ragent,et al.  Results of the Galileo Probe Nephelometer Experiment , 1996, Science.

[21]  J. Lunine,et al.  Enrichments in Volatiles in Jupiter: A New Interpretation of the Galileo Measurements , 2001 .

[22]  P. Drossart,et al.  Proximate humid and dry regions in Jupiter's atmosphere indicate complex local meteorology , 2000, Nature.

[23]  A. Chédin,et al.  The tropospheric gas composition of Jupiter's north equatorial belt /NH3, PH3, CH3D, GeH4, H2O/ and the Jovian D/H isotopic ratio , 1982 .

[24]  R. Carlson,et al.  The Origin of Belt/Zone Contrasts in the Atmosphere of Jupiter and Their Correlation with 5-μm Opacity , 2001 .

[25]  G. Orton,et al.  Evolution and persistence of 5‐μm hot spots at the Galileo probe entry latitude , 1998 .

[26]  H. Holweger.  Photospheric Abundances: Problems, Updates, Implications , 2001, astro-ph/0107426.

[27]  T. Geballe,et al.  The abundance of AsH3 in Jupiter , 1990 .

[28]  R. West,et al.  Jupiter's Cloud Structure from Galileo Imaging Data☆ , 1998 .

[29]  R. Wimmer–Schweingruber.  Joint SOHO/ACE workshop "Solar and Galactic Composition" , 2001 .

[30]  D. Hunten,et al.  The composition of the Jovian atmosphere as determined by the Galileo probe mass spectrometer. , 1998, Journal of geophysical research.

[31]  Imke de Pater,et al.  A low-temperature origin for the planetesimals that formed Jupiter , 1999, Nature.

[32]  K. Baines,et al.  Fresh Ammonia Ice Clouds in Jupiter: I. Spectroscopic Identification, Spatial Distribution, and Dynamical Implications , 2002 .

[33]  A. Cameron.  Elemental and Nuclidic Abundances in the Solar System , 1982 .

[34]  T. Geballe,et al.  The Origin and Vertical Distribution of Carbon Monoxide in Jupiter , 1988 .

[35]  T. Encrenaz,et al.  Constraints on the Tropospheric Cloud Structure of Jupiter from Spectroscopy in the 5-μm Region: A Comparison between Voyager/IRIS, Galileo/NIMS, and ISO/SWS Spectra☆ , 1999 .

[36]  T. Encrenaz,et al.  First results of ISO-SWS observations of Jupiter , 1996 .