Radar Backscatter and Emissivity Models of Proposed Pyroclastic Density Current Deposits on Venus

Ganesh, I.; Carter, Lynn M.; Henz, Triana N.

doi:10.1029/2022je007318

Cited by 5 publications

(2 citation statements)

References 69 publications

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“… 2017 ; Ganesh et al. 2022 ; Ghail and Wilson 2015 ; Keddie and Head 1995 ). The volatile content needed to produce an explosive eruption varies with the barometric pressure and therefore with vent altitude.…”

Section: Magmatic Volatiles - Which Gas Species Would Venus’ Volcanoe...mentioning

confidence: 99%

Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus

Wilson,

Marcq,

Gillmann

et al. 2024

Space Sci Rev

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This work reviews possible signatures and potential detectability of present-day volcanically emitted material in the atmosphere of Venus. We first discuss the expected composition of volcanic gases at present time, addressing how this is related to mantle composition and atmospheric pressure. Sulfur dioxide, often used as a marker of volcanic activity in Earth’s atmosphere, has been observed since late 1970s to exhibit variability at the Venus’ cloud tops at time scales from hours to decades; however, this variability may be associated with solely atmospheric processes. Water vapor is identified as a particularly valuable tracer for volcanic plumes because it can be mapped from orbit at three different tropospheric altitude ranges, and because of its apparent low background variability. We note that volcanic gas plumes could be either enhanced or depleted in water vapor compared to the background atmosphere, depending on magmatic volatile composition. Non-gaseous components of volcanic plumes, such as ash grains and/or cloud aerosol particles, are another investigation target of orbital and in situ measurements. We discuss expectations of in situ and remote measurements of volcanic plumes in the atmosphere with particular focus on the upcoming DAVINCI, EnVision and VERITAS missions, as well as possible future missions.

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Section: Magmatic Volatiles - Which Gas Species Would Venus’ Volcanoe...mentioning

confidence: 99%

Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus

Wilson,

Marcq,

Gillmann

et al. 2024

Space Sci Rev

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“…Magellan may also have observed active volcanism (e.g., Herrick & Hensley, 2023). At least some volcanic eruptions were explosive in the past (e.g., Airey et al, 2015;Ganesh, 2022;Ganesh et al, 2021Ganesh et al, , 2022. Lightning produced by either volcanic or atmospheric processes would provide a probe into Venus' current and past evolution.…”

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confidence: 99%

Meteors May Masquerade as Lightning in the Atmosphere of Venus

Blaske,

O'Rourke,

Desch

et al. 2023

JGR Planets

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Lightning in the atmosphere of Venus is either ubiquitous, rare, or non‐existent, depending on how one interprets diverse observations. Quantifying when and where, or even if lightning occurs would provide novel information about Venus’s atmospheric dynamics and chemistry. Lightning is also a potential risk to future missions, which could float in the cloud layers (∼50–70 km above the surface) for up to an Earth‐year. Over decades, spacecraft and ground‐based telescopes have searched for lightning at Venus using many instruments, including magnetometers, radios, and optical cameras. Two optical surveys (from the Akatsuki orbiter and the 61‐inch telescope on Mt. Bigelow, Arizona) observed several flashes at 777 nm (the unresolved triplet emission lines of excited atomic oxygen) that have been attributed to lightning. This conclusion is based, in part, on the statistical unlikelihood of so many meteors producing such energetic flashes, based in turn on the presumption that a low fraction (< 1%) of a meteor’s optical energy is emitted at 777 nm. We use observations of terrestrial meteors and analogue experiments to show that a much higher conversion factor (∼5–10%) should be expected. Therefore, we calculate that smaller, more numerous meteoroids could have caused the observed flashes. Lightning is likely too rare to pose a hazard to missions that pass through or dwell in the clouds of Venus. Likewise, small meteoroids burn up at altitudes of ∼100 km, roughly twice as high above the surface as the clouds, and also would not pose a hazard.

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Sedimentary Processes on Venus

Carter,

Gilmore,

Ghail

et al. 2023

Space Sci Rev

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The sedimentary cycle, including the processes of erosion, transport, and lithification, is a key part of how planets evolve over time. Early images of Venus’s vast volcanic plains, numerous volcanoes, and rugged tectonic regions led to the interpretation that Venus is a volcanic planet with little sediment cover and perhaps few processes for generating sedimentary rocks. However, in the years since the Magellan mission in the 1990s we have developed a better understanding of sedimentary process on Venus. Impact craters are the largest present-day source of sediments, with estimates from the current crater population suggesting an average sediment layer 8–63 cm in thickness if distributed globally. There is clear evidence of fine-grained material in volcanic summit regions that is likely produced through volcanism, and dune fields and yardangs indicate transport of sediments and erosion of rocks through wind. Landslides and fine-grained materials in highland tessera regions demonstrate erosive processes that move sediment downhill. It is clear that sediments are an important part of Venus’s geology, and it is especially important to realize that they mantle features that may be of interest to future landed or low-altitude imaging missions. The sinks of sediments are less well known, as it has been difficult to identify sedimentary rocks with current data. Layering observed in Venera images and in Magellan images of some tessera regions, as well as calculated rock densities, suggest that sedimentary rocks are present on Venus. New data is needed to fully understand and quantify the present-day sedimentary cycle and establish with certainty whether sedimentary rock packages do, in fact, exist on Venus. These data sets will need to include higher-resolution optical and radar imaging, experimental and geochemical measurements to determine how chemical weathering and lithification can occur, and topography to better model mesospheric winds. Sediments and sedimentary rocks are critical to understanding how Venus works today, but are also extremely important for determining how Venus’s climate has changed through time and whether it was once a habitable planet.

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Radar Backscatter and Emissivity Models of Proposed Pyroclastic Density Current Deposits on Venus

Cited by 5 publications

References 69 publications

Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus

Possible Effects of Volcanic Eruptions on the Modern Atmosphere of Venus

Meteors May Masquerade as Lightning in the Atmosphere of Venus

Sedimentary Processes on Venus

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