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We present an updated analysis of Jupiter’s equatorial meteorology from Cassini observations. For two months preceding the spacecraft’s closest approach, the Imaging Science Subsystem (ISS) onboard regularly imaged the atmosphere. We created time-lapse movies from this period in order to analyze the dynamics of equatorial hot spots and their interactions with adjacent latitudes. Hot spots are relatively...
A detailed study of the chevron-shaped dark spots on the strong southern equatorial wind jet near 7.5°S planetographic latitude shows variations in velocity with longitude and time. The presence of the large anticyclonic South Equatorial Disturbance (SED) has a profound effect on the chevron velocity, causing slower velocities to its east and increasing with distance from the disturbance. The chevrons...
The chromophores responsible for coloring the jovian atmosphere are embedded within Jupiter’s vertical aerosol structure. Sunlight propagates through this vertical distribution of aerosol particles, whose colors are defined by ϖ 0 (λ), and we remotely observe the culmination of the radiative transfer as I/F(λ). In this study, we employed a radiative transfer code to retrieve ϖ 0 (λ)...
We present a novel method of constructing streamlines to derive wind speeds within jovian vortices and demonstrate its application to Oval BA for 2001 pre-reddened Cassini flyby data, 2007 post-reddened New Horizons flyby data, and 1998 Galileo data of precursor Oval DE. Our method, while automated, attempts to combine the advantages of both automated and manual cloud tracking methods. The southern...
Hubble Space Telescope Wide Field Planetary Camera 2 imaging data of Jupiter were combined with wind profiles from Voyager and Cassini data to study long-term variability in Jupiter’s winds and cloud brightness. Searches for evidence of wind velocity periodicity yielded a few latitudes with potential variability; the most significant periods were found nearly symmetrically about the equator at 0°,...
Limb and nadir spectra acquired by Cassini/CIRS (Composite InfraRed Spectrometer) are analyzed in order to derive, for the first time, the meridional variations of diacetylene (C 4 H 2 ) and methylacetylene (CH 3 C 2 H) mixing ratios in Saturn’s stratosphere, from 5hPa up to 0.05hPa and 80°S to 45°N. We find that the C 4 H 2 and CH 3 C 2...
Five years of thermal infrared spectra from the Cassini Composite Infrared Spectrometer (CIRS) are analyzed to determine the response of Saturn’s atmosphere to seasonal changes in insolation. Hemispheric mapping sequences at 15.0cm −1 spectral resolution are used to retrieve the variation in the zonal mean temperatures in the stratosphere (0.5–5.0mbar) and upper troposphere (75–800mbar) between...
Measuring the spatial distribution of chemical compounds in Saturn’s stratosphere is critical to better understand the planet’s photochemistry and dynamics. Here we present an analysis of infrared spectra in the range 600–1400cm −1 acquired in limb geometry by the Cassini spacecraft between March 2005 and January 2008. We first determine the vertical temperature profiles from 3 to 0.01hPa,...
Observations made by the Imaging Science Subsystem (ISS), Visible and Infrared Mapping Spectrometer (VIMS) and the long-wavelength Composite Infrared Spectrometer (CIRS) aboard the Cassini spacecraft reveal that the large, long-lived cyclonic vortex at Saturn's south pole has a 4200-km-diameter cloud-free nearly circular region. This region has a 4 K warm core extending from the troposphere into the...
Hydrocarbons in the upper atmosphere of Saturn are known, from Voyager, ground-based, and early Cassini results, to vary in emission intensity with latitude. Of particular interest is the marked increase in hydrocarbon line intensity near the south pole during southern summer, as the increased line intensity cannot be simply explained by the increased temperatures observed in that region since the...
Jupiter's equatorial atmosphere, much like the Earth's, is known to show quasi-periodic variations in temperature, particularly in the stratosphere, but variations in other jovian atmospheric tracers have not been studied for any correlations to these oscillations. Data taken at NASA's Infrared Telescope Facility (IRTF) from 1979 to 2000 were used to obtain temperatures at two levels in the atmosphere,...
Jupiter's remaining White Oval changed color in late 2005 and became noticeably red in early 2006, as reported by amateur observers. We present wind and color analyses from high spatial resolution images taken with the Hubble Space Telescope Advanced Camera for Surveys in April 2006. These images suggest that the recent color change was tied to a strengthening of this storm, as implied by increased...
The Cassini Imaging Science Subsystem (ISS) and Composite Infrared Spectrometer (CIRS) reported a North Equatorial Belt (NEB) wave in Jupiter's atmosphere from optical images [Porco, C.C., and 23 colleagues, 2003. Science 299, 1541–1547] and thermal maps [Flasar, F.M., and 39 colleagues, 2004. Nature 427, 132–135], respectively. The connection between the two waves remained uncertain because the two...
Retrievals performed on Cassini Composite Infrared Spectrometer data obtained during the distant Jupiter flyby in 2000/2001 have been used to generate global temperature maps of the planet in the troposphere and stratosphere, but to higher latitudes than were shown previously by Flasar et al. [Flasar, F.M., 39 colleagues, 2004a. Nature 427, 132–135; Flasar, F.M., 44 colleagues, 2004b. Space Sci. Rev...
The changing size and aspect ratio of the Great Red Spot from 1880 to 2000 are reviewed, indicating that the length of the system has decreased significantly over the last 100 years and continues to decrease at present at a rate of 0.19 degrees per year. Voyager IRIS maps of para hydrogen fraction and potential temperature over the system are presented, showing the internal structure and surrounding...
Radiative transfer analysis was performed with data taken by the Galileo spacecraft Solid State Imager (SSI) during its nominal mission (December 1995 to December 1997). The objective is to use the methane band (727 and 889 nm) and color (410 and 756 nm) sensitivities to identify the vertical position of cloud absorption that leads to coloration. Earlier work (Banfield et al. 1998, Icarus135, 230-250)...
A principal components analysis was performed on Hubble Space Telescope WFPC2 images of Jupiter from October 1995 and October 1996. Global maps in the F410M, F555W, F673N, and F953N filters were analyzed. These are continuum wavelengths in Jupiter's spectrum, sensitive to reflection from the visible cloud deck. The primary principal components correspond approximately to gray spectral brightness variations,...
Possible water ice spectral signatures have been detected on Jupiter using Voyager Infrared Interferometer Spectrometer and Radiometer (IRIS) spectra taken near closest approach of the Voyager 1 and 2 missions. Comparison with simultaneous imaging data shows that these IRIS footprints approximately correspond to locations on the planet where deep convection is suspected. Of the sample of 7500+ spectra,...
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