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Sromovsky LA, Revercomb HE, Krauss RJ, Suomi VE. Voyager 2 observations of Saturn's northern mid-latitude cloud features: Morphology, motions, and evolution. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/ja088ia11p08650] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Smith BA, Soderblom LA, Beebe R, Bliss D, Boyce JM, Brahic A, Briggs GA, Brown RH, Collins SA, Cook AF, Croft SK, Cuzzi JN, Danielson GE, Davies ME, Dowling TE, Godfrey D, Hansen CJ, Harris C, Hunt GE, Ingersoll AP, Johnson TV, Krauss RJ, Masursky H, Morrison D, Owen T, Plescia JB, Pollack JB, Porco CC, Rages K, Sagan C, Shoemaker EM, Sromovsky LA, Stoker C, Strom RG, Suomi VE, Synnott SP, Terrile RJ, Thomas P, Thompson WR, Veverka J. Voyager 2 in the uranian system: imaging science results. Science 2010; 233:43-64. [PMID: 17812889 DOI: 10.1126/science.233.4759.43] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Voyager 2 images of the southern hemisphere of Uranus indicate that submicrometersize haze particles and particles of a methane condensation cloud produce faint patterns in the atmosphere. The alignment of the cloud bands is similar to that of bands on Jupiter and Saturn, but the zonal winds are nearly opposite. At mid-latitudes (-70 degrees to -27 degrees ), where winds were measured, the atmosphere rotates faster than the magnetic field; however, the rotation rate of the atmosphere decreases toward the equator, so that the two probably corotate at about -20 degrees . Voyager images confirm the extremely low albedo of the ring particles. High phase angle images reveal on the order of 10(2) new ringlike features of very low optical depth and relatively high dust abundance interspersed within the main rings, as well as a broad, diffuse, low optical depth ring just inside the main rings system. Nine of the newly discovered small satellites (40 to 165 kilometers in diameter) orbit between the rings and Miranda; the tenth is within the ring system. Two of these small objects may gravitationally confine the e ring. Oberon and Umbriel have heavily cratered surfaces resembling the ancient cratered highlands of Earth's moon, although Umbriel is almost completely covered with uniform dark material, which perhaps indicates some ongoing process. Titania and Ariel show crater populations different from those on Oberon and Umbriel; these were probably generated by collisions with debris confined to their orbits. Titania and Ariel also show many extensional fault systems; Ariel shows strong evidence for the presence of extrusive material. About halfof Miranda's surface is relatively bland, old, cratered terrain. The remainder comprises three large regions of younger terrain, each rectangular to ovoid in plan, that display complex sets of parallel and intersecting scarps and ridges as well as numerous outcrops of bright and dark materials, perhaps suggesting some exotic composition.
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Antonelli P, Revercomb HE, Sromovsky LA, Smith WL, Knuteson RO, Tobin DC, Garcia RK, Howell HB, Huang HL, Best FA. A principal component noise filter for high spectral resolution infrared measurements. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004jd004862] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- P. Antonelli
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - H. E. Revercomb
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - L. A. Sromovsky
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - W. L. Smith
- NASA Langley Research Center; Hampton Virginia USA
| | - R. O. Knuteson
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - D. C. Tobin
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - R. K. Garcia
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - H. B. Howell
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - H.-L. Huang
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
| | - F. A. Best
- Space Science Engineering Center; University of Wisconsin; Madison Wisconsin USA
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Sromovsky LA, Collard AD, Fry PM, Orton GS, Lemmon MT, Tomasko MG, Freedman RS. Galileo probe measurements of thermal and solar radiation fluxes in the Jovian atmosphere. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je01048] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sromovsky LA, Best FA, Collard AD, Fry PM, Revercomb HE, Freedman RS, Orton GS, Hayden JL, Tomasko MG, Lemmon MT. Solar and thermal radiation in Jupiter's atmosphere: initial results of the Galileo probe net flux radiometer. Science 1996; 272:851-4. [PMID: 8629018 DOI: 10.1126/science.272.5263.851] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The Galileo probe net flux radiometer measured radiation within Jupiter's atmosphere over the 125-kilometer altitude range between pressures of 0.44 bar and 14 bars. Evidence for the expected ammonia cloud was seen in solar and thermal channels down to 0.5 to 0.6 bar. Between 0.6 and 10 bars large thermal fluxes imply very low gaseous opacities and provide no evidence for a deep water cloud. Near 8 bars the water vapor abundance appears to be about 10 percent of what would be expected for a solar abundance of oxygen. Below 8 bars, measurements suggest an increasing water abundance with depth or a deep cloud layer. Ammonia appears to follow a significantly subsaturated profile above 3 bars. Unexpectedly high absorption of sunlight was found at wavelengths greater than 600 nanometers.
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Abstract
Voyager observations suggest that three of Neptune's major cloud features oscillate in latitude by 2 degrees to 4 degrees and that two of them simultaneously oscillate in longitude by 7.8 degrees and 98 degrees about their mean drift longitudes. The observations define most convincingly the two orthogonal oscillations of the second dark spot (near 53 degrees south). These oscillations have similar periods near 800 hours and approximately satisfy a simple advective model in which a latitudinal oscillation produces a phase-shifted longitudinal oscillation proportional to the local wind shear. The latitudinal motion of the Great Dark Spot can be fit with an oscillation period of about 2550 hours, whereas its dominant longitudinal motion, if oscillatory at all, has such a long period that it is not well constrained by the Voyager data.
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Smith WL, Revercomb HE, Howell HB, Huang HL, Knuteson RO, Koenig EW, LaPorte DD, Silverman S, Sromovsky LA, Woolf HM. GHIS—The GOES High-Resolution Interferometer Sounder. ACTA ACUST UNITED AC 1990. [DOI: 10.1175/1520-0450(1990)029<1189:gghris>2.0.co;2] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Smith BA, Soderblom LA, Banfield D, Barnet C, Basilevsky AT, Beebe RF, Bollinger K, Boyce JM, Brahic A, Briggs GA, Brown RH, Chyba C, Collins SA, Colvin T, Cook AF, Crisp D, Croft SK, Cruikshank D, Cuzzi JN, Danielson GE, Davies ME, De Jong E, Dones L, Godfrey D, Goguen J, Grenier I, Haemmerle VR, Hammel H, Hansen CJ, Helfenstein CP, Howell C, Hunt GE, Ingersoll AP, Johnson TV, Kargel J, Kirk R, Kuehn DI, Limaye S, Masursky H, McEwen A, Morrison D, Owen T, Owen W, Pollack JB, Porco CC, Rages K, Rogers P, Rudy D, Sagan C, Schwartz J, Shoemaker EM, Showalter M, Sicardy B, Simonelli D, Spencer J, Sromovsky LA, Stoker C, Strom RG, Suomi VE, Synott SP, Terrile RJ, Thomas P, Thompson WR, Verbiscer A, Veverka J. Voyager 2 at Neptune: Imaging Science Results. Science 1989; 246:1422-49. [PMID: 17755997 DOI: 10.1126/science.246.4936.1422] [Citation(s) in RCA: 106] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Voyager 2 images of Neptune reveal a windy planet characterized by bright clouds of methane ice suspended in an exceptionally clear atmosphere above a lower deck of hydrogen sulfide or ammonia ices. Neptune's atmosphere is dominated by a large anticyclonic storm system that has been named the Great Dark Spot (GDS). About the same size as Earth in extent, the GDS bears both many similarities and some differences to the Great Red Spot of Jupiter. Neptune's zonal wind profile is remarkably similar to that of Uranus. Neptune has three major rings at radii of 42,000, 53,000, and 63,000 kilometers. The outer ring contains three higher density arc-like segments that were apparently responsible for most of the ground-based occultation events observed during the current decade. Like the rings of Uranus, the Neptune rings are composed of very dark material; unlike that of Uranus, the Neptune system is very dusty. Six new regular satellites were found, with dark surfaces and radii ranging from 200 to 25 kilometers. All lie inside the orbit of Triton and the inner four are located within the ring system. Triton is seen to be a differentiated body, with a radius of 1350 kilometers and a density of 2.1 grams per cubic centimeter; it exhibits clear evidence of early episodes of surface melting. A now rigid crust of what is probably water ice is overlain with a brilliant coating of nitrogen frost, slightly darkened and reddened with organic polymer material. Streaks of organic polymer suggest seasonal winds strong enough to move particles of micrometer size or larger, once they become airborne. At least two active plumes were seen, carrying dark material 8 kilometers above the surface before being transported downstream by high level winds. The plumes may be driven by solar heating and the subsequent violent vaporization of subsurface nitrogen.
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Hammel HB, Beebe RF, De Jong EM, Hansen CJ, Howell CD, Ingersoll AP, Johnson TV, Limaye SS, Magalhaes JA, Pollack JB, Sromovsky LA, Suomi VE, Swift CE. Neptune's Wind Speeds Obtained by Tracking Clouds in Voyager Images. Science 1989; 245:1367-9. [PMID: 17798743 DOI: 10.1126/science.245.4924.1367] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Images of Neptune obtained by the narrow-angle camera of the Voyager 2 spacecraft reveal large-scale cloud features that persist for several months or longer. The features' periods of rotation about the planetary axis range from 15.8 to 18.4 hours. The atmosphere equatorward of -53 degrees rotates with periods longer than the 16.05-hour period deduced from Voyager's planetary radio astronomy experiment (presumably the planet's internal rotation period). The wind speeds computed with respect to this radio period range from 20 meters per second eastward to 325 meters per second westward. Thus, the cloud-top wind speeds are roughly the same for all the planets ranging from Venus to Neptune, even though the solar energy inputs to the atmospheres vary by a factor of 1000.
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Revercomb HE, Buijs H, Howell HB, Laporte DD, Smith WL, Sromovsky LA. Radiometric calibration of IR Fourier transform spectrometers: solution to a problem with the High-Resolution Interferometer Sounder. Appl Opt 1988; 27:3210-3218. [PMID: 20531920 DOI: 10.1364/ao.27.003210] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
A calibrated Fourier transform spectrometer, known as the High-Resolution Interferometer Sounder (HIS), has been flown on the NASA U-2 research aircraft to measure the infrared emission spectrum of the earth. The primary use-atmospheric temperature and humidity sounding-requires high radiometric precision and accuracy (of the order of 0.1 and 1 degrees C, respectively). To meet these requirements, the HIS instrument performs inflight radiometric calibration, using observations of hot and cold blackbody reference sources as the basis for two-point calibrations at each wavenumber. Initially, laboratory tests revealed a calibration problem with brightness temperature errors as large as 15 degrees C between 600 and 900 cm(-1). The symptom of the problem, which occurred in one of the three spectral bands of HIS, was a source-dependent phase response. Minor changes to the calibration equations completely eliminated the anomalous errors. The new analysis properly accounts for the situation in which the phase response for radiance from the instrument itself differs from that for radiance from an external source. The mechanism responsible for the dual phase response of the HIS instrument is identified as emission from the interferometer beam splitter.
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Tomasko MG, Smith PH, Suomi VE, Sromovsky LA, Revercomb HE, Taylor FW, Martonchik DJ, Seiff A, Boese R, Pollack JB, Ingersoll AP, Schubert G, Covey CC. The thermal balance of venus in light of the Pioneer Venus Mission. ACTA ACUST UNITED AC 1980. [DOI: 10.1029/ja085ia13p08187] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Schubert G, Covey C, Genio AD, Elson LS, Keating G, Seiff A, Young RE, Apt J, Counselman CC, Kliore AJ, Limaye SS, Revercomb HE, Sromovsky LA, Suomi VE, Taylor F, Woo R, von Zahn U. Structure and circulation of the Venus atmosphere. ACTA ACUST UNITED AC 1980. [DOI: 10.1029/ja085ia13p08007] [Citation(s) in RCA: 164] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Net radiation measurements in the atmosphere of Venus indicate that the bulk of the atmosphere is radiatively cooling at high latitudes and heating at low latitudes. Similarity of features observed by all three probes indicate planetwide stratification. Flux variations within the clouds provide evidence of significant differences in cloud structure. A feature of unusually large opacity found near 60 kilometers at the north probe site is probably related to the unique circulation regime revealed by ultraviolet and infrared imagery. A stable layer between the cloud bottoms and about 35 kilometers contains several features in the flux profiles probably resulting from large-scale compositional stratifications rather than clouds. In the layer below 35 kilometers unexpectedly large fluxes were observed.
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