&lt;title&gt;Cassini infrared Fourier spectroscopic investigation&lt;/title&gt;

Horn, L. ten; Kunde, V. G.; Ade, Peter A. R.; Barney, Richard D.; Bergman, D.; Bonnal, J.F.; Borelli, Rodolfo; Boyd, D.; Brasunas, J. C.; Brown, Gregory V.; Calcutt, S.; Carroll, Fred; Courtin, R.; Cretolle, J.; Crooke, Julie A.; Davis, Martin A.; Edberg, Stephen J.; Fettig, Rainer K.; Flasar, M.; Glenar, D. A.; Graham, Steve; Hagopian, John G.; Hakun, Claef; Hayes, Patricia A.; Herath, L.; Spilker, L. J.; Jennings, Donald E.; Karpati, Gabriel; Kellebenz, C.; Lakew, B.; Lindsay, J. C.; Lohr, J.; Lyons, James J.; Martineau, Robert J.; Martino, Anthony J.; Matsumura, Mack; McCloskey, John C.; Melak, T.; Molenaers, Guy; Morrell, Armando; Mosier, Carol L.; Pack, LaTunia G.; Plants, Michael; Robinson, David; Rodriguez, L.; Romani, P. N.; Schaefer, Bill; Schmidt, Stephen M.; Trujillo, Carlos; Vellacott, Tim; Wagner, K.; Yun, D.

doi:10.1117/12.253416

Cited by 70 publications

(21 citation statements)

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“…• W (Kunde et al, 1996;, coincident with Figure 1: The 'Voyager-NA' and 'Voyager-NQ' coadded spectra, and their differences, representing an auroral and quiescent region respectively. On the upper plots, the 1-σ noise levels are shown as error bars, calculated by scaling the NESR spectrum of Voyager 1-IRIS by a factor of 1/ √ N where N is the number of spectra averaged (Hanel et al, 1980;.…”

Section: Cassini-cirsmentioning

confidence: 54%

“…Cassini-CIRS (Composite Infrared Spectrometer, Kunde et al 1996;) is one such instrument, which measures mid-to-far infrared light from approximately 10 to 1600 cm −1 . Using a Michelson interferometer design, CIRS measures a spectrum of its target across three focal planes -FP1 (10 -600 cm −1 ), FP3 (600 -1100 cm −1 ) and FP4 (1100 -1400 cm −1 ) -and can operate at different spectral resolutions from 0.5 cm −1 to 15.0 cm −1 .…”

Section: Cassini-cirsmentioning

confidence: 99%

“…and Nixon et al (2010) used Cassini-CIRS and Voyager-IRIS zonally-averaged data to determine meridional variations in stratospheric temperature, C 2 H 2 and C 2 H 6 but avoided using spectra covering the auroral regions such that quiescent and auroral conditions were not averaged together. Kunde et al (1996) presented comparisons of observed and synthetic Cassini-CIRS spectra and used radiance contrasts between non-auroral and auroral regions to calculate the power emitted from auroral-related hotspots. presented brightness temperature variations and by comparing the morphology of the auroral-related hotspots at different wavenumbers that sounded different pressure regions, constrained that auroral heating must not penetrate below the 4-mbar level.…”

Section: Introductionmentioning

confidence: 99%

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Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

Sinclair

Orton

Greathouse

et al. 2017

Icarus

107

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Auroral processes are evident in Jupiter's polar atmosphere over a large range in wavelength (X-ray to radio). In particular, previous observations in the mid-infrared (5 to 15 µm) have shown enhanced emission from CH 4 , C 2 H 2 and C 2 H 4 and further stratospheric hydrocarbon species in spatial regions coincident with auroral processes observed at other wavelengths. These regions, described as auroral-related hotspots, observed at approximately 160• W to 200• W (System III) at high-northern latitudes and 330• W to 80• W at high-southern latitudes, indicate that auroral processes modify the thermal structure and composition of the neutral atmosphere. However, previous studies have struggled to differentiate whether the aforementioned enhanced emission is a result of either temperature changes and/or changes in the concentration of the emitting species. We attempt to address this degeneracy in this work by performing a retrieval analysis of Voyager 1-IRIS spectra (acquired in 1979) and Cassini-CIRS spectra (acquired in 2000/2001) of Jupiter. Retrievals of the vertical temperature profile in Cassini-CIRS spectra covering the auroral-related hotspots indicate the presence of two discrete vertical regions of heating at the 1-mbar level and at pressures of 10-µbar and lower. For example, in Cassini-CIRS 2.5 cm −1 'MIRMAP' spectra at 70• N (planetographic) 180• W (centred on the auroral oval), we find temperatures at the 1-mbar level and 10-µbar levels are enhanced by 15.3 ± 5.2 K and 29.6 ± 15.0 K respectively, in comparison to results at 70• N, 60• W in the same dataset. High temperatures at 10-µbar and lower pressures were considered indicative of joule heating, ion and/or electron precipitation, ion-drag and energy released form exothermic ion-chemistry. However, we conclude that the heating at the 1-mbar level is the result of either a layer of aurorally-produced haze particles, which are heated by incident sunlight and/or adiabatic heating by downwelling within the auroral hot-spot region. The former mechanism would be consistent with the vertical profiles of polycyclic aromatic hydrocarbons (PAHs) and haze particles predicted in auroral-chemistry models (Wong et al., 2000(Wong et al., , 2003. Retrievals of C 2 H 2 and C 2 H 6 were also performed and indicate C 2 H 2 is enriched but C 2 H 6 is depleted in auroral regions relative to quiescent regions. For example, using CIRS ∆ν = 2.5 cm −1 spectra, we determined that C 2 H 2 at 0.98 mbar increases by 175.3 ± 89.3 ppbv while C 2 H 6 at 4.7 mbar decreases by 0.86 ± 0.59 ppmv in comparing results at 70• N, 180• W and 70• N, 60• W. These results represent a mean of values retrieved from different initial assumptions and thus we believe they are robust. We believe these contrasts in C 2 H 2 and C 2 H 6 between auroral and quiescent regions can be explained by a coupling of auroral-driven chemistry and horizontal advection. Ion-neutral and electron recombination chemistry in the auroral region enriches all C 2 hydrocarbons but in particular, the unsaturated ...

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Section: Cassini-cirsmentioning

confidence: 54%

Section: Cassini-cirsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

Sinclair

Orton

Greathouse

et al. 2017

Icarus

107

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“…The gas chromatograph and mass spectrometer (GCMS) instrument aboard the Huygens Titan probe, to be launched into the atmosphere of Titan in January 2005, does not unfortunately have the mass resolution power mentioned above (Raulin 2001, private communication). However, the large number of remote sensing thermal infrared observations of the CH 3 D/CH 4 ratio to be made by the composite infrared spectrometer (CIRS) instrument aboard the Cassini orbiter (Kunde et al 1996), at various locations on the disk of the satellite, and during more than 40 fly-bys of Titan from 2004 to 2008, is expected to substantially improve the accuracy of the determination of the D/H ratio in the atmosphere of Titan. Moreover, the GCMS instrument will measure the abundances of noble gases, which may provide a test of our scenario (Paper I).…”

Section: Discussionmentioning

confidence: 99%

The D/H Ratio in Methane in Titan: Origin and History

Mousis

Gautier

Coustenis

2002

Icarus

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“…Zonal winds will also be derived from thermal infrared maps observed during a long period of time by the CIRS spectrometer onboard the Cassini spacecraft (Kunde et al 1996). Accompanying and follow-up ground-based observations will also be very useful.…”

Section: Discussion -Conclusionmentioning

confidence: 99%

Interferometric measurements of zonal winds on Titan

Moreno

Marten

Hidayat³

2005

A&A

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Abstract.We report millimetre observations of Titan performed with the IRAM Plateau de Bure Interferometer at the rotational frequencies of HC 3 N(25-24) and CH 3 CN(12-11). The most extended configuration of the array yielded disk-resolved emission spectra of Titan with an angular resolution of 0.6 . Data were acquired in February-March 2003 and February 2004 near the greatest eastern and western elongations of Titan at high spectral resolution (λ/∆λ = 5.5 × 10 6 ). Doppler lineshift measurements enable us to establish that the zonal wind flow is prograde in the upper atmosphere. Two different altitude regions are probed. Beam-integrated equatorial wind velocities of 160 (±60) m/s and 60 (±20) m/s are determined at respective altitudes of 300 (±150) km (upper stratosphere) and 450 (±100) km (lower mesosphere). The latter is the first direct determination of mesospheric wind speed on Titan.

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<title>Cassini infrared Fourier spectroscopic investigation</title>

Cited by 70 publications

References 0 publications

Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

Jupiter’s auroral-related stratospheric heating and chemistry I: Analysis of Voyager-IRIS and Cassini-CIRS spectra

The D/H Ratio in Methane in Titan: Origin and History

Interferometric measurements of zonal winds on Titan

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