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Transient surface liquid in Titan's polar regions from Cassini

dc.contributor.authorTHE CASSINI RADAR TEAM
hal.structure.identifierDivision of Geological and Planetary Sciences [Pasadena]
dc.contributor.authorHAYES, A. G.
hal.structure.identifierDivision of Geological and Planetary Sciences [Pasadena]
dc.contributor.authorAHARONSON, O.
hal.structure.identifierLunar and Planetary Laboratory [Tucson] [LPL]
dc.contributor.authorLUNINE, J.I.
hal.structure.identifierUS Geological Survey [Flagstaff]
dc.contributor.authorKIRK, R. L.
hal.structure.identifierDepartment of Electrical Engineering [Stanford]
dc.contributor.authorZEBKER, H. A.
hal.structure.identifierStanford University
dc.contributor.authorWYE, L. C.
hal.structure.identifierJohns Hopkins University Applied Physics Laboratory [Laurel, MD] [APL]
dc.contributor.authorLORENZ, R. D.
dc.contributor.authorTURTLE, E. P.
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
hal.structure.identifierUniversité Sciences et Technologies - Bordeaux 1 [UB]
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
dc.contributor.authorPAILLOU, Philippe
hal.structure.identifierJet Propulsion Laboratory [JPL]
dc.contributor.authorMITRI, G.
hal.structure.identifierJet Propulsion Laboratory [JPL]
dc.contributor.authorWALL, S. D.
hal.structure.identifierProxemy Research Inc
dc.contributor.authorSTOFAN, E. R.
hal.structure.identifierJet Propulsion Laboratory [JPL]
dc.contributor.authorMITCHELL, K. L.
hal.structure.identifierCalifornia Institute of Technology [CALTECH]
dc.contributor.authorELACHI, C.
dc.date.issued2011-01
dc.identifier.issn0019-1035
dc.description.abstractEnCassini RADAR images of Titan's south polar region acquired during southern summer contain lake features which disappear between observations. These features show a tenfold increases in backscatter cross-section between images acquired one year apart, which is inconsistent with common scattering models without invoking temporal variability. The morphologic boundaries are transient, further supporting changes in lake level. These observations are consistent with the exposure of diffusely scattering lakebeds that were previously hidden by an attenuating liquid medium. We use a two-layer model to explain backscatter variations and estimate a drop in liquid depth of approximately 1-m-per-year. On larger scales, we observe shoreline recession between ISS and RADAR images of Ontario Lacus, the largest lake in Titan's south polar region. The recession, occurring between June 2005 and July 2009, is inversely proportional to slopes estimated from altimetric profiles and the exponential decay of near-shore backscatter, consistent with a uniform reduction of 4 ± 1.3 m in lake depth.Of the potential explanations for observed surface changes, we favor evaporation and infiltration. The disappearance of dark features and the recession of Ontario's shoreline represents volatile transport in an active methane-based hydrologic cycle. Observed loss rates are compared and shown to be consistent with available global circulation models. To date, no unambiguous changes in lake level have been observed between repeat images in the north polar region, although further investigation is warranted. These observations constrain volatile flux rates in Titan's hydrologic system and demonstrate that the surface plays an active role in its evolution. Constraining these seasonal changes represents the first step toward our understanding of longer climate cycles that may determine liquid distribution on Titan over orbital time periods.
dc.language.isoen
dc.publisherElsevier
dc.titleTransient surface liquid in Titan's polar regions from Cassini
dc.typeArticle de revue
dc.identifier.doi10.1016/J.ICARUS.2010.08.017
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Planétologie et astrophysique de la terre [astro-ph.EP]
bordeaux.journalIcarus
bordeaux.page655-671
bordeaux.volume211
bordeaux.peerReviewedoui
hal.identifierhal-00572393
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00572393v1
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