Lightning storms on Saturn observed by Cassini ISS and RPWS during 2004–2006

Dyudina, Ulyana A.; Ingersoll, Andrew P.; Ewald, S. P.; Porco, C. C.; Fischer, G.; Kurth, W. S.; Desch, M. D.; Genio, Anthony D. Del; Barbara, J.; Ferrier, Joseph

doi:10.1016/j.icarus.2007.03.035

Cited by 75 publications

(105 citation statements)

References 21 publications

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“…If the anomaly corresponds to a large-scale m = 3 perturbation in the planet's envelope, then V d will be of order R 3 s and the density perturbation may be only one part in 10 11 . However, if the anomalies are associated with something comparable in scale to Saturn's storm clouds (∼ 2000 km, Dyudina et al 2007), then the density contrast could be more like 10 −6 . Unless these anomalies have a pure m = 3 structure inside the planet, we would expect additional gravitational tesseral resonances to be found elsewhere in the main rings.…”

Section: Multiple M = +3 Waves In the Outer C Ringmentioning

confidence: 99%

More Kronoseismology with Saturn's rings

Hedman

Nicholson

2014

Monthly Notices of the Royal Astronomical Society

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In a previous paper (Hedman and Nicholson 2013), we developed tools which allowed us to confirm that several of the waves in Saturn's rings were likely generated by resonances with fundamental sectoral normal modes inside Saturn itself. Here we use these same tools to examine eight additional waves that are probably generated by structures inside the planet. One of these waves appears to be generated by a resonance with a fundamental sectoral normal mode with azimuthal harmonic number m = 10. If this attribution is correct, then the m = 10 mode must have a larger amplitude than the modes with m = 5 − 9, since the latter do not appear to generate strong waves. We also identify five waves with pattern speeds between 807 • /day and 834 • /day. Since these pattern speeds are close to the planet's rotation rate, they probably are due to persistent gravitational anomalies within the planet. These waves are all found in regions of enhanced optical depth known as plateaux, but surprisingly the surface mass densities they yield are comparable to the surface mass densities of the background C ring. Finally, one wave appears to be a one-armed spiral pattern whose rotation rate suggests it is generated by a resonance with a structure inside Saturn, but the nature of this perturbing structure remains unclear. Strangely, the resonant radius for this wave seems to be drifting inwards at an average rate of 0.8 km/year over the last thirty years, implying that the relevant planetary oscillation frequency has been steadily increasing.

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Section: Multiple M = +3 Waves In the Outer C Ringmentioning

confidence: 99%

More Kronoseismology with Saturn's rings

Hedman

Nicholson

2014

Monthly Notices of the Royal Astronomical Society

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“…They drift slowly in either direction relative to the mean zonal flow at 0-10 m s -1 . In between, convective activity occurs with some regularity, interacting with the vortex circulation (Sromovsky et al 2003;Porco et al 2005;Dyudina et al 2007). report observed episodes of formation and disappearances of vortices suggestive of particular physical mechanisms.…”

Section: Anti-cyclonic and Cyclonic Vorticesmentioning

confidence: 99%

Saturn Atmospheric Structure and Dynamics

Genio

Achterberg

Baines

et al. 2009

Saturn From Cassini-Huygens

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“…Particularly interesting is the strong cyclonic vortex found around the Southern Pole [18]. (2) Convective storms are relatively common at mid-latitudes [29,30] and probably fuelled by "moist" ammonia and water vapour latent heat release [31]. A major event are the "Great White Spots" (GWS) that occur sporadically in Saturn (mainly at equatorial latitudes) attaining a size of 20,000 km before they spread zonally [32].…”

Section: Meteorology and Atmospheric Dynamicsmentioning

confidence: 99%

“…In ways that are still not fully understood, moist convection works rather differently from terrestrial storms, due to the very low mean molecular weight of the atmosphere. As on Jupiter [39], lightning may also accompany vigorous convection at times, though detection at Saturn in association with particular convective events has been more elusive [30].…”

Section: Meteorology and Atmospheric Dynamicsmentioning

confidence: 99%

Kronos: exploring the depths of Saturn with probes and remote sensing through an international mission

et al. 2008

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Kronos is a mission aimed to measure in situ the chemical and isotopic compositions of the Saturnian atmosphere with two probes and also by remote sensing, in order to understand the origin, formation, and evolution of giant planets in general, including extrasolar planets. Xe/ 129 Xe isotopic ratios will be measured by mass spectrometry on two probes entering the atmosphere of Saturn at two different locations near mid-latitudes, down to a pressure of 10 Bar. The global composition of Saturn will be investigated through these measurements, together with microwave radiometry determination of H 2 O and NH 3 and their 3D variations. The dynamics of Saturn's atmosphere will be investigated from: (1) measurements of pressure, temperature, vertical distribution of clouds and wind speed along the probes' descent trajectories, and (2) determination of deep winds, differential rotation and convection with combined probe, gravity and radiometric measurements. Besides these primary goals, Kronos will also measure the intensities and characteristics of Saturn's magnetic field inside the D ring as well as Saturn's gravitational field, in order to constrain the abundance of heavy elements in Saturn's interior and in its central core. Depending on the preferred architecture (flyby versus orbiter), Kronos will be in a position to measure the properties of Saturn's innermost magnetosphere and to investigate the ring structure in order to understand how these tiny structures could have formed and survived up to the present times.

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Lightning storms on Saturn observed by Cassini ISS and RPWS during 2004–2006

Cited by 75 publications

References 21 publications

More Kronoseismology with Saturn's rings

More Kronoseismology with Saturn's rings

Saturn Atmospheric Structure and Dynamics

Kronos: exploring the depths of Saturn with probes and remote sensing through an international mission

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