ABSTRACT
The Cassini spacecraft orbiting Saturn carries the composite infrared spectrometer (CIRS) designed to study thermal emission from Saturn and its rings and moons. CIRS, a Fourier transform spectrometer, is an indispensable part of the payload providing unique measurements and important synergies with the other instruments. It takes full advantage of Cassini's 13-year-long mission and surpasses the capabilities of previous spectrometers on Voyager 1 and 2. The instrument, consisting of two interferometers sharing a telescope and a scan mechanism, covers over a factor of 100 in wavelength in the mid and far infrared. It is used to study temperature, composition, structure, and dynamics of the atmospheres of Jupiter, Saturn, and Titan, the rings of Saturn, and surfaces of the icy moons. CIRS has returned a large volume of scientific results, the culmination of over 30 years of instrument development, operation, data calibration, and analysis. As Cassini and CIRS reach the end of their mission in 2017, we expect that archived spectra will be used by scientists for many years to come.
ABSTRACT
This publisher's note renumbers the reference list in Appl. Opt.56, 5274 (2017)APOPAI0003-693510.1364/AO.56.005274.
ABSTRACT
Temperatures obtained from early Cassini infrared observations of Titan show a stratopause at an altitude of 310 kilometers (and 186 kelvin at 15 degrees S). Stratospheric temperatures are coldest in the winter northern hemisphere, with zonal winds reaching 160 meters per second. The concentrations of several stratospheric organic compounds are enhanced at mid- and high northern latitudes, and the strong zonal winds may inhibit mixing between these latitudes and the rest of Titan. Above the south pole, temperatures in the stratosphere are 4 to 5 kelvin cooler than at the equator. The stratospheric mole fractions of methane and carbon monoxide are (1.6 +/- 0.5) x 10(-2) and (4.5 +/- 1.5) x 10(-5), respectively.
Subject(s)
Hydrocarbons , Methane , Nitriles , Saturn , Atmosphere , Carbon Monoxide , Extraterrestrial Environment , Spacecraft , Temperature , WindABSTRACT
Stratospheric temperatures on Saturn imply a strong decay of the equatorial winds with altitude. If the decrease in winds reported from recent Hubble Space Telescope images is not a temporal change, then the features tracked must have been at least 130 kilometers higher than in earlier studies. Saturn's south polar stratosphere is warmer than predicted from simple radiative models. The C/H ratio on Saturn is seven times solar, twice Jupiter's. Saturn's ring temperatures have radial variations down to the smallest scale resolved (100 kilometers). Diurnal surface temperature variations on Phoebe suggest a more porous regolith than on the jovian satellites.
Subject(s)
Saturn , Atmosphere , Carbon , Extraterrestrial Environment , Hydrogen , Methane , Spacecraft , Spectrum Analysis , Temperature , WindABSTRACT
The Composite Infrared Spectrometer observed Jupiter in the thermal infrared during the swing-by of the Cassini spacecraft. Results include the detection of two new stratospheric species, the methyl radical and diacetylene, gaseous species present in the north and south auroral infrared hot spots; determination of the variations with latitude of acetylene and ethane, the latter a tracer of atmospheric motion; observations of unexpected spatial distributions of carbon dioxide and hydrogen cyanide, both considered to be products of comet Shoemaker-Levy 9 impacts; characterization of the morphology of the auroral infrared hot spot acetylene emission; and a new evaluation of the energetics of the northern auroral infrared hot spot.
Subject(s)
Carbon Dioxide , Hydrocarbons , Hydrogen Cyanide , Jupiter , Acetylene , Atmosphere , Ethane , Extraterrestrial Environment , Spacecraft , Spectrum Analysis , TemperatureABSTRACT
Infrared emission spectra of effluents from the smokestacks of typical small buildings were observed remotely using a Fourier transform infrared (FTIR) spectrometer. The primary purpose of the study was to determine the best method for distinguishing gas from oil as the fuel being burned in a building's furnace. Spectral pattern recognition techniques were employed to suppress the strong and highly varying background to the extent required to extract the very weak molecular emission features from the effluent spectra. It was found that several prominent H(2)0 and CO(2) transitions could be used to discriminate between the combustion products of gas and oil by determining the H(2)O/CO(2) concentration ratio in the exhaust gases.
ABSTRACT
Previous work dealing with the planning of outpatient health care has primarily used either linear programming or simulation. Linear programs are rather severe abstractions of reality. Simulation models are more realistic but are very expensive and do not necessarily identify optimal solutions. This paper discusses a recursive optimization-stimulation approach, which takes advantage of the best features of both methods while minimizing the disadvantages of each method used alone. A mixed integer program generates staffing and facility plans, thus reducing the number of alternatives requiring analysis via simulation. The simulation model then evaluates the acceptability of alternative plans, considering detailed information and complex relationships omitted from the optimization model. The method is used in a hypothetical example based on data from a variety of sources. The results from the example demonstrate the value of the recursive method; however, they are not to be used in a general context.
