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IRIS Derived Atmospheric Parameters for Jupiter and Saturn (PDS)


Availability: At NSSDC, Ready for Offline Distribution (or Staging if Digital)


These data consist of atmospheric parameters derived from infrared spectra obtained by the Voyager 1 and 2 Infrared Interferometer Spectrometer (IRIS) experiment during the Jupiter and Saturn encounters. There are three PDS data sets represented.

The Jupiter and Saturn north/south data sets were derived from measurements obtained during north/south mapping sequences in which the planet was mapped in the latitude range of approximately 60 degrees S and 60 degrees N. The instrument was repeatedly scanned from north to south as the planet rotated under the spacecraft through roughly 360 degrees of longitude. Two maps for each planet are included, one taken as the spacecraft approached the planet on the day side and the other taken as the spacecraft moved away from the planet on the night side.

The third data set was derived from measurements of Jupiter's Great Red Spot (GRS) and surrounds. They are derived from a number of different sequences, including one known as the 'GRS Cross', acquired by Voyager 1, which consisted of north/south and east-west scans through the GRS. Data records from Voyager 2 in this set are derived from a GRS mosaic at a relatively higher resolution. The remaining records are from miscellaneous Voyager 1 sequences.

The derived atmospheric parameters from all three data sets include atmospheric temperatures at the 143 mbar and 267 mbar levels, the fraction of molecular hydrogen in the para state at a level nominally centered near 300 mbar, cloud optical depths at 226/cm and 2060/cm, and the ammonia mole fraction at 600 mbar relative to the equivalent solar value (0.000178).

In addition to the derived atmospheric parameters, integrated measurements from the broad-band visible radiometer are included as well as brightness temperatures associated with the radiances used in the derivations. Further provided are: the solar zenith angle for the central point of the field of view projected onto the planet, the slant distance (km) from the spacecraft to the central point, the latitude and longitude of the central point, and eight additional points equally spaced around the periphery of the field of view.

Documentation describing the organization and content of the data files are included as is information regarding the processing, data coverage, and overall quality of the data.

Alternate Names

  • PDS IRIS Derived Atmos. Params.
  • Voyager 1 & 2 Jupiter IRIS Derived Great Red Spot Parameters V1.0
  • Voyager 1 & 2 Jupiter IRIS Derived North/South Parameters V1.0
  • Voyager 1 & 2 Saturn IRIS derived North/South Parameters V1.0


  • Planetary Science: Atmospheres


  • 77-076A-03I
  • 77-084A-03E

Additional Information



Questions and comments about this data collection can be directed to: Dr. Edwin V. Bell, II



NameRoleOriginal AffiliationE-mail
Dr. Barney J. ConrathData ProviderNASA Goddard Space Flight Center
Dr. Steven W. LeeGeneral ContactUniversity of

Selected References

  • Conrath, B. J., and P. J. Gierasch, Retrieval of ammonia abundances and cloud opacities on Jupiter from Voyager IRIS spectra, Icarus, 67, No. 3, 444-455, doi:10.1016/0019-1035(86)90124-7, Sept. 1986.
  • Conrath, B. J., and P. J. Gierasch, Global variation of the para hydrogen fraction in Jupiter's atmosphere and implications for dynamics on the outer planets, Icarus, 57, No. 2, 184-204, doi:10.1016/0019-1035(84)90065-4, Feb. 1984.
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