Search Publications
GCM simulations of Titan's middle and lower atmosphere and comparison to observations
Lunine, Jonathan I.; Lora, Juan M.; Russell, Joellen L.
Simulation results are presented from a new general circulation model (GCM) of Titan, the Titan Atmospheric Model (TAM), which couples the Flexible Modeling System (FMS) spectral dynamical core to a suite of external/sub-grid-scale physics. These include a new non-gray radiative transfer module that takes advantage of recent data from Cassini-Huyg…
Seasonal variations in Titan's middle atmosphere during the northern spring derived from Cassini/CIRS observations
Bézard, Bruno; Vinatier, Sandrine; Achterberg, Richard K. +8 more
We analyzed spectra acquired at the limb of Titan in the 2006-2013 period by the Cassini/Composite Infrared Spectrometer (CIRS) in order to monitor the seasonal evolution of the thermal, gas composition and aerosol spatial distributions. We are primarily interested here in the seasonal changes after the northern spring equinox and interpret our re…
Titan's atmosphere as observed by Cassini/VIMS solar occultations: CH4, CO and evidence for C2H6 absorption
Nicholson, Philip D.; Maltagliati, Luca; Bézard, Bruno +6 more
We present an analysis of the VIMS solar occultations dataset, which allows us to extract vertically resolved information on the characteristics of Titan's atmosphere between ∼100 and 700 km with a vertical resolution of ∼10 km. After a series of data treatment procedures to correct problems in pointing stability and parasitic light, 4 occultation…
Saturn's variable thermosphere from Cassini/UVIS occultations
Sandel, B. R.; Erwin, J. T.; Strobel, D. F. +3 more
We retrieved the density and temperature profiles in Saturn's thermosphere from 26 stellar occultations observed by the Cassini/UVIS instrument. These results expand upon and complement the previous analysis of 15 Cassini/UVIS solar occultations by Saturn's upper thermosphere. We find that the exospheric temperatures based on the stellar occultati…
Seasonal evolution of Saturn's polar temperatures and composition
Fletcher, Leigh N.; Irwin, P. G. J.; Orton, G. S. +7 more
The seasonal evolution of Saturn's polar atmospheric temperatures and hydrocarbon composition is derived from a decade of Cassini Composite Infrared Spectrometer (CIRS) 7-16 µm thermal infrared spectroscopy. We construct a near-continuous record of atmospheric variability poleward of 60° from northern winter/southern summer (2004, Ls
Cloud structure and composition of Jupiter's troposphere from 5- µ m Cassini VIMS spectroscopy
Fletcher, L. N.; Irwin, P. G. J.; Giles, R. S.
Jupiter's tropospheric composition and cloud structure are studied using Cassini VIMS 4.5-5.1 µ m thermal emission spectra from the 2000-2001 flyby. We make use of both nadir and limb darkening observations on the planet's nightside, and compare these with dayside observations. Although there is significant spatial variability in the 5- &mic…
Saturn kilometric radiation periodicity after equinox
Gurnett, D. A.; Kurth, W. S.; Ye, S. -Y. +2 more
The rotation period of Saturn's magnetosphere was found to vary with time, and changing periodicities were identified in magnetic fields, radio emissions, and charged particles. Here we analyze the varying period of Saturn kilometric radiation (SKR) from 2009 to early 2013, i.e. mainly after Saturn equinox of August 2009. A periodicity analysis is…
Seasonal changes in Saturn's stratosphere inferred from Cassini/CIRS limb observations
Flasar, F. M.; Spiga, A.; Fouchet, T. +4 more
We present temperature and hydrocarbons abundances (C2H6, C2H2, C3H8) retrieved from Cassini/CIRS limb spectra, acquired during northern spring in 2010 (LS = 12 °) and 2012 (LS = 31 °). We compare them to the previous limb measurements performed by Guerlet et a…
Evolution of stratospheric chemistry in the Saturn storm beacon region
Fletcher, Leigh N.; Irwin, Patrick G. J.; Moses, Julianne I. +4 more
The giant northern-hemisphere storm that erupted on Saturn in December 2010 triggered significant changes in stratospheric temperatures and species abundances that persisted for more than a year after the original outburst. The stratospheric regions affected by the storm have been nicknamed "beacons" due to their prominent infrared-emission signat…
Cassini INMS measurements of Enceladus plume density
McNutt, R. L.; Waite, J. H.; Teolis, B. D. +5 more
During six encounters between 2008 and 2013, the Cassini Ion and Neutral Mass Spectrometer (INMS) made in situ measurements deep within the Enceladus plumes. Throughout each encounter, those measurements contained density variations that reflected the nature of the source, particularly of the high-velocity jets. Since the dominant constituent of t…