Photographs of Venus

Ross, Frank E.

doi:10.1086/143130

Cited by 58 publications

(18 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These UV markings were first reported by Wright [1927] and Ross [1928]. The more recent ground-based observations by Coffeen [1971] and Woodman and Barker [1973] Of the absorbing constituents suggested for the Venus atmosphere, the most popular was certainly solid sulfur suggested by Young [1977].…”

Section: Introductionmentioning

confidence: 79%

Ultraviolet contrasts and the absorbers near the Venus cloud tops

Esposito¹

1980

J. Geophys. Res.

View full text Add to dashboard Cite

The absorbers in the Venus atmosphere are not merely markers for the atmospheric motions; their absorption of incident sunlight determines the deposition of the energy which drives these motions. Measurements of the ultraviolet contrasts constrain the location, altitude, and identity of these absorbers near the Venus cloud tops. Spin‐scan images from the Pioneer Venus orbiter UV spectrometer (UVS) and the cloud photopolarimeter (CPP) provide a set of planetary contrast measurements in the wavelength range from 1990 Å to 3650 Å and phase angles from 33° to 130°. The planet is darkest at the point where the UVS line of sight penetrates perpendicular to the cloud tops: thus the absorbing material responsible must be deep in the atmosphere. Sulfur dioxide absorption can explain the amount of contrast seen between 2000 Å and 3200 Å. At the longer wavelengths (where the SO2 cross section has dropped by 2 orders of magnitude), the persistence of contrast requires another absorber which is deeper in the atmosphere than the SO2 (at about the 75‐mbar level). This additional absorption is strongly (but not identically) associated with the location of the SO2; we find the short and long wavelength images are remarkably similar. Part of the observed contrast is due to the high‐lying haze discovered from Pioneer Venus polarimetry, most importantly at the shortest wavelengths where CO2 is strongly absorbing. The correlation between planetary contrast and polarization does not require large‐scale clearing or major vertical motions of the cloud tops as the sole cause of the observed contrast. However, a scheme in which absorbers subject to photochemical destruction are mixed upward into the cloud top region provides a consistent explanation for the origin of these markings.

show abstract

Section: Introductionmentioning

confidence: 79%

Ultraviolet contrasts and the absorbers near the Venus cloud tops

Esposito¹

1980

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…Venus clouds are complex as we have discovered. The ultraviolet contrasts were first discovered more than a century ago (Ross 1928), and the suggestion that the clouds were made of droplets containing sulfuric acid solutions (Young 1973) was confirmed more than 4 decades ago (Hansen and Hovenier 1974). But, we still do not know the species which are responsible for the dayside contrasts seen in the dayside cloud cover, except that sulfur dioxide gas is one of them and there is at least one other absorber which is as yet unknown (Travis 1975).…”

Section: Nightside Images Of Venus In Near Infraredmentioning

confidence: 99%

“…The contrasts on Venus were noticed more than a century ago and recorded as drawings as early as 1881 (Niesten and Stuyvaert 1904). Venus was photographed by several observers in blue-violet as early as the 1920s (Ross 1927(Ross , 1928Slipher 1931). Subsequently, when more frequent ultraviolet images were obtained, it was realized that Venus showed a lot of variability, and hence, the images revealed clouds rather than features on the surface (Claydes 1909).…”

Section: Introductionmentioning

confidence: 99%

Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images

Limaye

Watanabe

Yamazaki

et al. 2018

Earth Planets Space

View full text Add to dashboard Cite

Since insertion into orbit on December 7, 2015, the Akatsuki orbiter has returned global images of Venus from its four imaging cameras at eleven discrete wavelengths from ultraviolet (283 and 365 nm) and near infrared (0.9-2.3 µm), to the thermal infrared (8-12 µm) from a near-equatorial orbit. The Venus Express and Pioneer Venus Orbiter missions have also monitored the planet for long periods but from polar or near-polar orbits. The wavelength coverage and views of the planet also differ for all three missions. In reflected light, the images reveal features seen near the cloud tops (~ 70 km altitude), whereas in the near-infrared images of the nightside, features seen are at mid-to lower cloud levels (~ 48-60 km altitude). The dayside cloud cover imaged at the ultraviolet wavelengths shows morphologies similar to what was observed from Mariner 10, Pioneer Venus, Galileo, Venus Express and MESSENGER. The daytime images at 0.9 and 2.02 µm also reveal some interesting features which bear similarity to the ultraviolet images. The nighttime images at 1.74, 2.26 and 2.32 µm and at 8-12 µm reveal features not seen before and show new details of the nightside including narrow wavy ribbons, curved string-like features, long-scale waves, long dark streaks, isolated bright spots, sharp boundaries and even mesoscale vortices. Some features previously seen such as circum-equatorial belts (CEBs) and occasional areal brightenings at ultraviolet (seen in Venus Express observations) of the cloud cover at ultraviolet wavelengths have not been observed thus far. Evidence for the hemispheric vortex organization of the global circulation can be seen at all wavelengths on the day-and nightsides. Akatsuki images reveal new and puzzling morphology of the complex nightside cloud cover. The cloud morphologies provide some clues to the processes occurring in the atmosphere and are thus, a key diagnostic tool when quantitative dynamical analysis is not feasible due to insufficient information.

show abstract

“…Therefore, in contrast to the featureless visible-wavelength Venus images, the UV images present unique cloud morphologies, including the well-known "Yfeature, " which is even observable from ground-based stations (Dollfus 1975). The Venus UV image observations have about 90 years of history starting from the first ground-based observations (Wright 1927;Ross 1928) to the Hubble space telescope (Na and Esposito 1995); several spacecraft observations were performed using flyby opportunities [Mariner 10 (Murray et al 1974), Galileo (Belton et al 1991) and Messenger], and using Venus orbiters [Venera (Ksanfomaliti et al 1978), Pioneer Venus Pollack et al 1979;Stewart et al 1979), and Venus Express (Markiewicz et al 2007a, b;Titov et al 2008Titov et al , 2012]. …”

Section: Introductionmentioning

confidence: 99%

Ultraviolet imager on Venus orbiter Akatsuki and its initial results

Yamazaki

Yamada

Lee

et al. 2018

Earth Planets Space

View full text Add to dashboard Cite

The ultraviolet imager (UVI) has been developed for the Akatsuki spacecraft (Venus Climate Orbiter mission). The UVI takes ultraviolet (UV) images of the solar radiation reflected by the Venusian clouds with narrow bandpass filters centered at the 283 and 365 nm wavelengths. There are absorption bands of SO 2 and unknown absorbers in these wavelength regions. The UV images provide the spatial distribution of SO 2 and the unknown absorber around cloud top altitudes. The images also allow us to understand the cloud top morphologies and haze properties. Nominal sequential images with 2-h intervals are used to understand the dynamics of the Venusian atmosphere by estimating the wind vectors at the cloud top altitude, as well as the mass transportation of UV absorbers. The UVI is equipped with off-axial catadioptric optics, two bandpass filters, a diffuser installed in a filter wheel moving with a step motor, and a high sensitivity charge-coupled device with UV coating. The UVI images have spatial resolutions ranging from 200 m to 86 km at sub-spacecraft points. The UVI has been kept in good condition during the extended interplanetary cruise by carefully designed operations that have maintained its temperature maintenance and avoided solar radiation damage. The images have signal-to-noise ratios of over 100 after onboard desmear processing. Keywords: Venus orbiter

show abstract

Photographs of Venus

Cited by 58 publications

References 0 publications

Ultraviolet contrasts and the absorbers near the Venus cloud tops

Ultraviolet contrasts and the absorbers near the Venus cloud tops

Venus looks different from day to night across wavelengths: morphology from Akatsuki multispectral images

Ultraviolet imager on Venus orbiter Akatsuki and its initial results

Contact Info

Product

Resources

About