Microwave imaging of Saturn's deep atmosphere and rings

Miscellaneous · Mon Jan 01 00:00:00 EST 1990

OSTI ID:5392267

Grossman, A W

An analysis of microwave images of Saturn's atmosphere and rings is presented. Interferometer observations at wavelengths of 0.27, 2.01, 6.17, and 20.13 cm, and precise application of synthesis imaging techniques yielded brightness and polarization maps of unsurpassed resolution and sensitivity. Linear polarization is detected from the ring ansea, and brightness variations in the deep atmosphere and the rings are revealed. The disk-integrated spectrum of Saturn is interpreted within the context of a radiative transfer model that requires the NH{sub 3} mixing ratio to take on a value of 0.9 to 1.1 x 10{sup -} directly below the ammonia ice cloud at a pressure of 1.4 bar. The NH{sub 3} mixing ratio increases with depth to a value of 5.0 to 6.5 x 10{sup -} at a pressure of 6 bar. The variation of NH{sub 3} with depth can be entirely accounted for by the presence of 11 to 14 times solar abundance of H{sub 2}S, which reacts with NH{sub 3} to produce a substantial NH{sub 4}SH cloud. Latitudinal variations in brightness temperature indicate that the saturated vapor abundance of ammonia decreases by 50 percent from equator to pole within the cloud deck. At greater depths, the latitudinal variations of ammonia are consistent with alternating zones of concentration and depletion caused by vertical motions. An apparent depletion in northern mid-lattitudes is well-correlated with a decrease in infrared opacity and depressed cloud top levels, indicating deep-seated downwelling. The size, composition, and shape of particles comprising the rings of Saturn are constrained by modeling the emission, scattering, and extinction of radiation by the rings. Azimuthal variations in brightness and linear polarization favor a model in which the particles are irregularly shaped.

• Research Organization: California Inst. of Tech., Pasadena, CA (United States)
• OSTI ID: 5392267
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
SATURN PLANET
MICROWAVE SPECTRA
PLANETARY ATMOSPHERES
AMMONIA
BRIGHTNESS
CHEMICAL COMPOSITION
EXPERIMENTAL DATA
HEAT TRANSFER
HYDROGEN SULFIDES
ICE
ATMOSPHERES
CHALCOGENIDES
DATA
ENERGY TRANSFER
HYDRIDES
HYDROGEN COMPOUNDS
INFORMATION
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NUMERICAL DATA
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
PLANETS
SPECTRA
SULFIDES
SULFUR COMPOUNDS
640107* - Astrophysics & Cosmology- Planetary Phenomena