Titan haze distribution and optical properties retrieved from recent observations

Rannou, P.; Cours, Thibaud; Mouëlic, Stéphane Le; Rodríguez, S.; Sotin, C.; Drossart, P.; Brown, R. H.

doi:10.1016/j.icarus.2010.03.016

Cited by 91 publications

(113 citation statements)

References 62 publications

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“…The scaling factor f h , not shown here, varies from about 0.9 at 50 • N to about 0.7 at 75 • N. However, the variation of f h shows that the GCM needs a small correction, as already concluded by Rannou et al (2010). Table 2 shows a correlation matrix for the retrieval taken at T 22 and T 51 , and at three specific latitudes around 55 • N, 62 • N, and 70 • N. The correlation terms are generally quite high.…”

Section: Evolution Of the Haze And Cloud In The Polar Regionsupporting

confidence: 74%

“…In any case, the fit at 2.0 μm is poor in quality. The window at 2.8 μm is very complicated because deuterated methane absorbs in the middle of the window (Nikitin et al 2006), optical constants of aerosols have a strong variation between 2.4 and 3 μm (Rannou et al 2010), and finally an absorption feature is missing in the model at 2.75 μm. The 2.8 μm window is extremely interesting because it contains much information and, moreover, is one of the clearest windows.…”

Section: Analysis Procedures and Resultsmentioning

confidence: 99%

“…The haze layer is assumed to be made of aggregates of about 3000 spheres of 0.05 μm (Tomasko et al 2008). To compute the haze optical properties, we use the optical constants published by Rannou et al (2010). In the range of interest, these have only small differences with the Khare et al (1984) index because we avoid the 2.80 μm window and the band at 3.4 μm where atmospheric properties are still not well defined.…”

Section: The Model and Datamentioning

confidence: 99%

“…In order to show that this structure corresponds to the ring already observed in the past, we performed dedicated computations of the outgoing intensity that should be observed at visible wavelengths with the haze and droplet layer properties retrieved in this work. To extrapolate the atmospheric properties with the wavelength, we use the optical constants retrieved in Rannou et al (2010) for the photochemical aerosols. We assume that the mist is a mixture of aerosols and hydrocarbon droplets of 3 μm, with optical constants similar to that of methane.…”

Section: Winter Spring Ringmentioning

confidence: 99%

“…On each selected image, we study a latitudinal cut that encompasses parts of the planet where we have a mixture of haze and mist without cloud and parts where the cloud can be seen. Spectra are simulated using the model described in Rannou et al (2010). In Section 2 we briefly describe the model, present the data, and give arguments to explain the spectral bands that were used in the analysis.…”

Section: Introductionmentioning

confidence: 99%

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CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

Rannou¹,

Mouëlic²,

Sotin³

et al. 2012

ApJ

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A large cloud in the north polar region of Titan was first observed by the Visual and Infrared Mapping Spectrometer (VIMS) in 2005 and then in 2006. This cloud, confined beyond the latitude 62 • N, is surrounded by a mixture of aerosol and mist probably lying in the low stratosphere and troposphere. Subsequent images of this region of Titan show a gradual vanishing of this cloud which was reported previously. In this paper, we characterize the physical properties of this cloud, haze, and mist as well as their time evolutions. We note several details on the images such as a secondary cloud above the main cloud and latitudes beyond 70 • N. We also show that the cloud disappearance leaves the polar region poorly loaded in aerosols, yielding an annular zone of aerosols between 50 • N and 65 • N. Our analysis suggests that this structure observed by VIMS in the near-IR is an annular structure observed by ISS on board Voyager one Titan year ago in 1980.

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Section: Evolution Of the Haze And Cloud In The Polar Regionsupporting

confidence: 74%

Section: Analysis Procedures and Resultsmentioning

confidence: 99%

Section: The Model and Datamentioning

confidence: 99%

Section: Winter Spring Ringmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

Rannou¹,

Mouëlic²,

Sotin³

et al. 2012

ApJ

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Thermal radiation of magma ocean planets using a 1‐D radiative‐convective model of H₂O‐CO₂ atmospheres

et al. 2017

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This paper presents an updated version of the simple 1‐D radiative‐convective H2O‐CO2 atmospheric model from Marcq (2012) and used by Lebrun et al. (2013) in their coupled interior‐atmosphere model. This updated version includes a correction of a major miscalculation of the outgoing longwave radiation (OLR) and extends the validity of the model (P coordinate system, possible inclusion of N2, and improved numerical stability). It confirms the qualitative findings of Marcq (2012), namely, (1) the existence of a blanketing effect in any H2O‐dominated atmosphere: the outgoing longwave radiation (OLR) reaches an asymptotic value, also known as Nakajima's limit and first evidenced by Nakajima et al. (1992), around 280 W/m2 neglecting clouds, significantly higher than our former estimate from Marcq (2012). (2) The blanketing effect breaks down for a given threshold temperature Tϵ, with a fast increase of OLR with increasing surface temperature beyond this threshold, making extrasolar planets in such an early stage of their evolution easily detectable near 4 μm provided they orbit a red dwarf. Tϵ increases strongly with H2O surface pressure, but increasing CO2 pressure leads to a slight decrease of Tϵ. (3) Clouds act both by lowering Nakajima's limit by up to 40% and by extending the blanketing effect, raising the threshold temperature Tϵ by about 10%.

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Titan's atmosphere and climate

2017

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Titan is the only moon with a substantial atmosphere, the only other thick N2 atmosphere besides Earth's, the site of extraordinarily complex atmospheric chemistry that far surpasses any other solar system atmosphere, and the only other solar system body with stable liquid currently on its surface. The connection between Titan's surface and atmosphere is also unique in our solar system; atmospheric chemistry produces materials that are deposited on the surface and subsequently altered by surface‐atmosphere interactions such as aeolian and fluvial processes resulting in the formation of extensive dune fields and expansive lakes and seas. Titan's atmosphere is favorable for organic haze formation, which combined with the presence of some oxygen‐bearing molecules indicates that Titan's atmosphere may produce molecules of prebiotic interest. The combination of organics and liquid, in the form of water in a subsurface ocean and methane/ethane in the surface lakes and seas, means that Titan may be the ideal place in the solar system to test ideas about habitability, prebiotic chemistry, and the ubiquity and diversity of life in the universe. The Cassini‐Huygens mission to the Saturn system has provided a wealth of new information allowing for study of Titan as a complex system. Here I review our current understanding of Titan's atmosphere and climate forged from the powerful combination of Earth‐based observations, remote sensing and in situ spacecraft measurements, laboratory experiments, and models. I conclude with some of our remaining unanswered questions as the incredible era of exploration with Cassini‐Huygens comes to an end.

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Titan haze distribution and optical properties retrieved from recent observations

Cited by 91 publications

References 62 publications

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

Thermal radiation of magma ocean planets using a 1‐D radiative‐convective model of H₂O‐CO₂ atmospheres

Titan's atmosphere and climate

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Titan haze distribution and optical properties retrieved from recent observations

Cited by 91 publications

References 62 publications

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

CLOUD AND HAZE IN THE WINTER POLAR REGION OF TITAN OBSERVED WITH VISUAL AND INFRARED MAPPING SPECTROMETER ON BOARDCASSINI

Thermal radiation of magma ocean planets using a 1‐D radiative‐convective model of H2O‐CO2 atmospheres

Titan's atmosphere and climate

Contact Info

Product

Resources

About

Thermal radiation of magma ocean planets using a 1‐D radiative‐convective model of H₂O‐CO₂ atmospheres