Infrared spectrometer for Voyager

Hanel, Reinhold; Crosby, David F.; Herath, L.; Vanous, D.; Collins, Daniel J.; Creswick, H.; Harris, C.R.; Rhodes, M.

doi:10.1364/ao.19.001391

Cited by 80 publications

(43 citation statements)

References 5 publications

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“…The noise equivalent spectral radiance (NESR) of Voyager 1 IRIS in the 280 -600 cm -1 spectral region does not exceed 5.10 -9 watts em -2 sr-1/cm-1 (Hanel et al, 1980) which results in a signal to noise ratio per spectrum of about 300 at 285 em -1 and 30 at 600 cm -1 . There values correspond to errors in brightness temperatures of about 0.15K at 295 em -1 and 0.5K at 600 Cm -1.…”

Section: Ir Is-radio Occultation Methodsmentioning

confidence: 98%

The helium abundance of Jupiter from Voyager

Gautier¹,

Conrath²,

Flasar³

et al. 1981

J. Geophys. Res.

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113

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Section: Ir Is-radio Occultation Methodsmentioning

confidence: 98%

The helium abundance of Jupiter from Voyager

Gautier¹,

Conrath²,

Flasar³

et al. 1981

J. Geophys. Res.

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113

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“…Voyager/IRIS (Infrared Spectrometer and Radiometer, Hanel et al, 1980) data was extracted from the VG2001 archive on the Planetary Data System 1 . The dataset extends over the three days surrounding closest approach (August 23-26 1989, spacecraft flight data system (FDS) count 1133200-1144200).…”

Section: Reanalysis Of Voyager/iris Spectramentioning

confidence: 99%

Neptune at summer solstice: Zonal mean temperatures from ground-based observations, 2003–2007

Fletcher

Pater²,

Orton

et al. 2014

Icarus

108

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• ). Our aim was to analyse imaging and spectroscopy from multiple different sources using a single self-consistent radiative-transfer model to assess the magnitude of seasonal variability. Globally-averaged stratospheric temperatures measured from methane emission tend towards a quasi-isothermal structure (158-164 K) above the 0.1-mbar level, and are found to be consistent with spacecraft observations of AKARI. This remarkable consistency, despite very different observing conditions, suggests that stratospheric temporal variability, if present, is < ±5 K at 1 mbar and < ±3 K at 0.1 mbar during this solstice period. Conversely, ethane emission is highly variable, with abundance determinations varying by more than a factor of two (from 500 to 1200 ppb at 1 mbar). The retrieved C 2 H 6 abundances are extremely sensitive to the details of the T (p) derivation, although the underlying cause of the variable ethane emission remains unidentified. Stratospheric temperatures and ethane are found to be latitudinally uniform away from the south pole (assuming a latitudinally-uniform distribution of stratospheric methane), with no large seasonal hemispheric asymmetries evident at solstice. At low and mid-latitudes, comparisons of synthetic Voyager-era images with solstice-era observations suggest that tropospheric zonal temperatures are unchanged since the Voyager 2 encounter, with cool mid-latitudes and a warm equator and pole. A re-analysis of Voyager/IRIS 25-50 µm mapping of tropospheric temperatures and para-hydrogen disequilibrium (a tracer for vertical motions) suggests a symmetric meridional circulation with cold air rising at mid-latitudes (sub-equilibrium para-H 2 conditions) and warm air sinking at the equator and poles (super-equilibrium para-H 2 conditions). The most significant atmospheric changes have occurred at high southern latitudes, where zonal temperatures retrieved from 2003 images suggest a polar enhancement of 7-8 K above the tropopause, and an increase of 5-6 K throughout the 70 − 90• S region between 0.1 and 200 mbar. Such a large perturbation, if present in 1989, would have been detectable by Voyager/IRIS in a single scan despite its long-wavelength sensitivity, and we conclude that Neptune's south polar cyclonic vortex increased in strength significantly from Voyager to solstice.

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“…Data were obtained throughout the flyby, and spectra with nearly global coverage were obtained during north-south mapping sequences performed about three million km from Jupiter. The IRIS instrument was a dual interferometerradiometer with a shared 0.25" (4.36 milliradian) circular field of view (Hanel et al 1977(Hanel et al , 1980a(Hanel et al , 1980b. The single-channel radiometer was sensitive from -33-2 microns (Hanel et al 1980a), while the Michelson interferometer was sensitive to radiation from 200 to 2500 cm-' (-4-50 microns) with an apodized spectral resolution of 4.3 cm-I.…”

Section: I the Fourier Transform Spectrometersmentioning

confidence: 99%