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Mapping polar atmospheric features on Titan with VIMS: from the dissipation of the northern cloud to the onset of a southern polar vortex
- Source :
- Icarus, Icarus, Elsevier, 2018, 311, pp.371-383. ⟨10.1016/j.icarus.2018.04.028⟩
- Publication Year :
- 2018
-
Abstract
- We have analyzed the complete archive of the Visual and Infrared Mapping Spectrometer (VIMS) data in order to monitor and analyze the evolution of the clouds and haze coverage at both poles of Titan during the entire Cassini mission. Our objective is to give a cartographic synopsis from a VIMS perspective, to provide a global view of the seasonal evolution of Titan's atmosphere over the poles. We leave the detailed comparison with the Imaging Science Subsystem (ISS) and the Composite Infrared Spectrometer (CIRS) data sets to further studies. We have computed global hyperspectral mosaics for each of the 127 targeted flybys of Titan to produce synthetic color maps emphasizing the main atmospheric features. The north pole appears fully covered by a huge cloud as soon as the first observations in 2004 and up to the equinox in 2009 (Le Mou\'elic et al. 2012). The northern skies then became progressively clearer, after the circulation turnover in 2009, revealing the underlying lakes and seas to the optical instruments up to 2017. The reverse situation is observed over the south pole, which was mostly clear of such a high obscuring cloud during the first years of the mission, but started to develop a polar cloud in 2012. This feature grew up month after month until the end of the mission in 2017, with a poleward latitudinal extent of 75$^\circ$S in 2013 up to 58$^\circ$S in April 2017. Thanks to the spectral capabilities of VIMS, we have detected HCN spectral signatures over the north pole in almost all flybys between 2004 and 2008. These HCN signatures started then to show up over the south pole in almost all flybys between 2012 and 2017, so perfectly matching the timing and spatial extent of the northern and southern polar atmospheric features.
- Subjects :
- Haze
010504 meteorology & atmospheric sciences
FOS: Physical sciences
Equinox
01 natural sciences
symbols.namesake
Polar vortex
0103 physical sciences
Atmosphere of Titan
[MATH]Mathematics [math]
010303 astronomy & astrophysics
ComputingMilieux_MISCELLANEOUS
0105 earth and related environmental sciences
[PHYS]Physics [physics]
Earth and Planetary Astrophysics (astro-ph.EP)
Spectral signature
Spectrometer
Astronomy and Astrophysics
13. Climate action
Space and Planetary Science
[SDU]Sciences of the Universe [physics]
Climatology
symbols
Polar
Titan (rocket family)
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Geology
Astrophysics - Earth and Planetary Astrophysics
Subjects
Details
- Language :
- English
- ISSN :
- 00191035 and 10902643
- Database :
- OpenAIRE
- Journal :
- Icarus, Icarus, Elsevier, 2018, 311, pp.371-383. ⟨10.1016/j.icarus.2018.04.028⟩
- Accession number :
- edsair.doi.dedup.....e4bf50f52ffe85c729b3e821e0f5ef3f