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Texture and composition of Titan's equatorial sand seas inferred from Cassini SAR data: Implications for aeolian transport and dune morphodynamics

hal.structure.identifierInstitut de Physique du Globe de Paris [IPGP]
dc.contributor.authorLUCAS, Antoine
hal.structure.identifierInstitut de Physique du Globe de Paris [IPGP]
dc.contributor.authorRODRIGUEZ, Sébastien
hal.structure.identifierLaboratoire de Météorologie Dynamique (UMR 8539) [LMD]
dc.contributor.authorLEMONNIER, Florentin
hal.structure.identifierPLANETO - LATMOS
dc.contributor.authorLE GALL, Alice
hal.structure.identifierDepartment of Physics [Moscow,USA]
dc.contributor.authorMACKENZIE, Shannon
hal.structure.identifierInstitut de Physique du Globe de Paris [IPGP]
dc.contributor.authorFERRARI, Cécile
hal.structure.identifierASP 2019
hal.structure.identifierObservatoire Bordeaux
dc.contributor.authorPAILLOU, Philippe
hal.structure.identifierInstitut de Physique du Globe de Paris [IPGP]
dc.contributor.authorNARTEAU, Clément
dc.date.issued2019-10-18
dc.identifier.issn2169-9097
dc.description.abstractEnThe texture, composition, and morphology of dunes observed in the equatorial regions of Titan may reflect present and/or past climatic conditions. Determining the physio‐chemical properties and the morphodynamics of Titan's dunes is therefore essential to understanding of the climatic and geological history of the largest moon of Saturn. We quantitatively derived average surface properties of dune and interdune areas (texture, composition) from modeling of the microwave backscattered signal and Monte‐Carlo inversion of the despeckled Cassini/SAR data over Titan's three largest sand seas: Belet, Shangri‐La and Fensal. We present the first analysis of the backscatter functions extracted from despeckled SAR images that cover such a large range in incidence angles, including data from the beginning of the Cassini mission up to its Grand Finale. We show that dunes and interdunes have significantly different physical properties. Dunes are found to be more microwave absorbent than interdunes. Additionally, potential secondary bedforms, such as ripples and avalanches, may have been detected, providing potential evidence for currently active dunes and sediment transport. Our modelling shows that the interdunes have multi‐scale roughnesses with higher dielectric constants than the dunes which have a low dielectric constant consistent with organic sand. The radar brightness of the interdunes can be explained by the presence of a shallow layer of significantly larger organic grains, possibly non‐mobilized by the winds. Together, our findings suggest that Titan's sand seas evolve under the current multi‐directional wind regimes with dunes that elongate with their crests aligned in the residual drift direction.
dc.description.sponsorshipEarth - Planets - Universe: observation, modeling, transfer
dc.description.sponsorshipUniversité Sorbonne Paris Cité - ANR-11-IDEX-0005
dc.language.isoen
dc.publisherWiley-Blackwell
dc.title.enTexture and composition of Titan's equatorial sand seas inferred from Cassini SAR data: Implications for aeolian transport and dune morphodynamics
dc.typeArticle de revue
dc.identifier.doi10.1029/2019JE005965
dc.subject.halPlanète et Univers [physics]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.identifier.arxiv1702.02881v2
bordeaux.journalJournal of Geophysical Research. Planets
bordeaux.page3140-3163
bordeaux.volume124
bordeaux.issue11
bordeaux.peerReviewedoui
hal.identifierinsu-02320751
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//insu-02320751v1
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