The Clouds and Hazes of Venus

Esposito, L. W.; Knollenberg, Robert G.; Marov, Mikhail Ya.; Toon, O. B.; Turco, R. P.

doi:10.2307/j.ctv25c4z16.20

Cited by 27 publications

(27 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…H3PO3 is a vanishingly small fraction of the total phosphorus inventory; if the cloud droplets contain 1 molar H3PO4, then the concentration of H3PO3 would be ~6.10 -17 molar at the cloud base (47 km) and at ~10 -21 molar at the altitude above which PH3 was detected (~55 km). If we assume that the total volume of cloud material is ~1.10 10 m 3 (calculated from the droplet sizes and abundances as a function of altitude as listed in (Esposito et al 1983)), the clouds about 47 km would contain ~44 milligrams of H3PO3 in the whole Venusian atmosphere. Reduction of phosphate to phosphite by atmospheric components and subsequent disproportionation of phosphite to phosphine is therefore extremely unlikely to be the mechanism responsible for Venus's phosphine.…”

Section: 1 2 Formation Of Phosphine In the Venusian Atmosphere-surfac...mentioning

confidence: 99%

Phosphine on Venus Cannot Be Explained by Conventional Processes

et al. 2021

View full text Add to dashboard Cite

The recent candidate detection of ~20 ppb of phosphine in the middle atmosphere of Venus is so unexpected that it requires an exhaustive search for explanations of its origin. Phosphoruscontaining species have not been modelled for Venus' atmosphere before and our work represents the first attempt to model phosphorus species in Venusian atmosphere. We thoroughly explore the potential pathways of formation of phosphine in a Venusian environment, including in the planet's atmosphere, cloud and haze layers, surface, and subsurface. We investigate gas reactions, geochemical reactions, photochemistry, and other non-equilibrium processes. None of these potential phosphine production pathways are sufficient to explain the presence of ppb phosphine levels on Venus. The presence of PH3, therefore, must be the result of a process not previously considered plausible for Venusian conditions. The process could be unknown geochemistry, photochemistry, or even aerial microbial life, given that on Earth phosphine is exclusively associated with anthropogenic and biological sources. The detection of phosphine adds to the complexity of chemical processes in the Venusian environment and motivates in situ follow up sampling missions to Venus.

show abstract

Section: 1 2 Formation Of Phosphine In the Venusian Atmosphere-surfac...mentioning

confidence: 99%

Phosphine on Venus Cannot Be Explained by Conventional Processes

et al. 2021

View full text Add to dashboard Cite

show abstract

“…Venus is known as a unique terrestrial planet that is covered by thick global sulfuric acid clouds. The clouds significantly regulate the climate on Venus by influencing the atmospheric radiative balance via its high albedo and large infrared opacity (e.g., Arney et al., 2014; Esposito et al., 1983; Seiff et al., 1985; Titov et al., 2018; Tomasko, Smith, et al., 1980). Strong convection in the cloud layers impacts the general circulation and zonal winds on Venus (e.g., Bertaux et al., 2016; Gierasch, 1987).…”

Section: Introductionmentioning

confidence: 99%

“…The cloud droplets on Venus are mainly composed of concentrated sulfuric acid solution (H 2 SO 4 and H 2 O), along with some contaminants like ferric chloride (FeCl 3 ), polysulfide (S n ), and ferric sulfate (Fe 2 (SO4) 3 ; Esposito et al., 1983; Krasnopolsky, 1985). The cloud acidity—H 2 SO 4 weight percent in the droplet—is estimated to be 75%–92% (Arney et al., 2014; Barstow et al., 2012; Cottini et al., 2012; Hansen & Hovenier, 1974; McGouldrick et al., 2021; Pollack et al., 1978).…”

Section: Introductionmentioning

confidence: 99%

A Simple Condensation Model for the H₂SO₄‐H₂O Gas‐Cloud System on Venus

et al. 2022

View full text Add to dashboard Cite

The current Venus climate is largely regulated by globally covered concentrated sulfuric acid clouds from binary condensation of sulfuric acid (H2SO4) and water (H2O). To understand this complicated H2SO4‐H2O gas‐cloud system, previous theoretical studies either adopted complicated microphysical calculations or assumed that both H2SO4 and H2O vapor follow their saturation vapor pressure. In this study, we developed a simple one‐dimensional cloud condensation model including condensation, diffusion and sedimentation of H2SO4 and H2O but without detailed microphysics. Our model is able to explain the observed vertical structure of cloud and upper haze mass loading, cloud acidity, H2SO4, and H2O vapor, and the mode‐2 particle size on Venus. We found that most H2SO4 is stored in the condensed phase above 48 km, while the partitioning of H2O between the vapor and clouds is complicated. The cloud cycle is mostly driven by evaporation and condensation of H2SO4 rather than H2O and is about seven times stronger than the H2SO4 photochemical cycle. Most of the condensed H2O in the upper clouds is evaporated before the falling particles reach the middle clouds. The cloud acidity is affected by the temperature and the condensation‐evaporation cycles of both H2SO4 and H2O. Because of the large chemical production of H2SO4 vapor and relatively inefficient cloud condensation, the simulated H2SO4 vapor above 60 km is largely supersaturated by more than two orders of magnitude, which could be tested by future observations.

show abstract

“…The globally distributed clouds on Venus are mainly composed of concentrated sulfuric acid (H 2 SO 4 , Esposito et al 1983;Krasnopolsky 1985). Their formation is governed by complex microphysical processes (Gao et al 2014;Imamura & Hashimoto 2001;James et al 1997;McGouldrick 2017;McGouldrick & Toon 2007;Parkinson et al 2015;Rossow 1977;Rossow & Gierasch 1977), such as condensation, evaporation, nucleation, coagulation, as well as coalescence.…”

Section: Introductionmentioning

confidence: 99%

A Fast, Semi-analytical Model for the Venusian Binary Cloud System

Dai,

Zhang,

Cui

2022

Preprint

View full text Add to dashboard Cite

The Venusian clouds originate from the binary condensation of H 2 SO 4 and H 2 O. The two components strongly interact with each other via chemistry and cloud formation. Previous works adopted sophisticated microphysical approaches to understand the clouds. Here we show that the observed vapor and cloud distributions on Venus can be well explained by a semi-analytical model. Our model assumes local thermodynamical equilibrium for water vapor but not for sulfuric acid vapor, and includes the feedback of cloud condensation and acidity to vapor distributions. The model predicts strong supersaturation of the H 2 SO 4 vapor above 60 km, consistent with our recent cloud condensation model. The semi-analytical model is 100 times faster than the condensation model and 1000 times faster than the microphysical models. This allows us to quickly explore a large parameter space of the sulfuric acid gas-cloud system. We found that the cloud mass loading in the upper clouds has an opposite response of that in the lower clouds to the vapor mixing ratios in the lower atmosphere. The transport of water vapor influences the cloud acidity in all cloud layers while the transport of sulfuric acid vapor only dominates in the lower clouds. This cloud model is fast enough to be coupled with the climate models and chemistry models to understand the cloudy atmospheres of Venus and Venus-like extra-solar planets.

show abstract

The Clouds and Hazes of Venus

Cited by 27 publications

References 0 publications

Phosphine on Venus Cannot Be Explained by Conventional Processes

Phosphine on Venus Cannot Be Explained by Conventional Processes

A Simple Condensation Model for the H₂SO₄‐H₂O Gas‐Cloud System on Venus

A Fast, Semi-analytical Model for the Venusian Binary Cloud System

Contact Info

Product

Resources

About

The Clouds and Hazes of Venus

Cited by 27 publications

References 0 publications

Phosphine on Venus Cannot Be Explained by Conventional Processes

Phosphine on Venus Cannot Be Explained by Conventional Processes

A Simple Condensation Model for the H2SO4‐H2O Gas‐Cloud System on Venus

A Fast, Semi-analytical Model for the Venusian Binary Cloud System

Contact Info

Product

Resources

About

A Simple Condensation Model for the H₂SO₄‐H₂O Gas‐Cloud System on Venus