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Title: DISTRIBUTION OF CO{sub 2} IN SATURN'S ATMOSPHERE FROM CASSINI/CIRS INFRARED OBSERVATIONS

This paper focuses on the CO{sub 2} distribution in Saturn's atmosphere based on analysis of infrared spectral observations of Saturn made by the Composite Infrared Spectrometer aboard the Cassini spacecraft. The Cassini spacecraft was launched in 1997 October, inserted in Saturn's orbit in 2004 July, and has been successfully making infrared observations of Saturn, its rings, Titan, and other icy satellites during well-planned orbital tours. The infrared observations, made with a dual Fourier transform spectrometer in both nadir- and limb-viewing modes, cover spectral regions of 10-1400 cm{sup –1}, with the option of variable apodized spectral resolutions from 0.53 to 15 cm{sup –1}. An analysis of the observed spectra with well-developed radiative transfer models and spectral inversion techniques has the potential to provide knowledge of Saturn's thermal structure and composition with global distributions of a series of gases. In this paper, we present an analysis of a large observational data set for retrieval of Saturn's CO{sub 2} distribution utilizing spectral features of CO{sub 2} in the Q-branch of the ν{sub 2} band, and discuss its possible relationship to the influx of interstellar dust grains. With limited spectral regions available for analysis, due to low densities of CO{sub 2} and interference frommore » other gases, the retrieved CO{sub 2} profile is obtained as a function of a model photochemical profile, with the retrieved values at atmospheric pressures in the region of ∼1-10 mbar levels. The retrieved CO{sub 2} profile is found to be in good agreement with the model profile based on Infrared Space Observatory measurements with mixing ratios of ∼4.9 × 10{sup –10} at atmospheric pressures of ∼1 mbar.« less
Authors:
;  [1] ; ; ;  [2] ; ; ; ; ;  [3] ;  [4] ;
  1. NASA-Marshall Space Flight Center, Huntsville, AL 35812 (United States)
  2. University of Alabama in Huntsville, Huntsville, AL 35899 (United States)
  3. NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States)
  4. University of Maryland, College Park, MD 20742 (United States)
Publication Date:
OSTI Identifier:
22270757
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 776; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ASTRONOMY; ASTROPHYSICS; ATMOSPHERIC PRESSURE; CARBON DIOXIDE; COSMIC DUST; FOURIER TRANSFORM SPECTROMETERS; GASES; INFRARED SPECTRA; INFRARED SPECTROMETERS; INTERSTELLAR GRAINS; MIXING RATIO; PHOTOCHEMISTRY; RADIANT HEAT TRANSFER; SATELLITE ATMOSPHERES; SATURN PLANET