Atmosphere Of Venus Research Articles

Return to Earth: A New Mathematical Model of the Earth’s Climate

In this paper we use the inverse modelling technique, first applied to the atmosphere of the planet Venus, to demonstrate that the process of convective atmospheric mass motion can be invoked to explain the greenhouse effect of the Earth’s climate. We propose that the atmospheric cell is the fundamental element of climate, and have developed an alternative climate model based on this process of atmospheric circulation for a hypothetical tidally locked world. The concept of climate derives from studies by the Greek philosopher Aristotle, who identified the three main climatic zones known to the ancient world; the equatorial torrid zone, the polar frigid zone and in between the favoured temperate zone of the Mediterranean world. Aristotle’s three climatic zones can be directly linked to the three main atmospheric circulation cells that we now recognise within the Earth’s atmosphere. These three cells are the Hadley cell, the Polar cell and the Ferrel cell. Based on the clear association between the traditional Greek concept of climate and the modern meteorological concept of atmospheric circulation cells, we propose that climate be defined as the presence and action of a particular circulation cell type within a given planetary latitudinal zone. We discuss how with knowledge of three simple meteorological parameters of tropopause elevation, tropopause temperature and lapse rate for each atmospheric cell, combined with the measurement of the area of that cell, the average global surface temperature can be calculated. By means of a mathematical model, the Dynamic-Atmosphere Energy-Transport (DAET) climate model we apply an individual climate analysis to each of the three atmospheric cells, and next generate a parallel composite model of the Earth’s planetary climate using these data. We apply the concepts and techniques of the adiabatic version of the DAET climate model, and show how this model can be compared with the published NASA image of the Earth’s outgoing long-wave radiation recorded by the CERES (Clouds and the Earth’s Radiant Energy System) Instrument onboard the NASA Aqua Satellite. Our analysis of the CERES image suggests that the Tibetan plateau forms a permanent geological thermal radiant leak point in the Earth’s atmosphere. We also compare the observed temperature found at the maximum elevation of the Antarctic ice cap with the freezing point of super-cooled water, and suggest that there is therefore a temperature controlled and latent heat related upper limit to the vertical development of a continental icecap.

THz generation from laser-induced breakdown in pressurized molecular gases: on the way to terahertz remote sensing of the atmospheres of Mars and Venus

The present paper studies the generation of terahertz (THz) radiation in CO2 in comparison with atmospheric air at a wide range of pressures. We established experimentally and explained theoretically that for these gases there are optimal pressures at about 1 bar for air and 0.5 bar for CO2 under which the efficiency of conversion from near-infrared to THz frequencies is the highest. We consider the possibility of applying femtosecond laser-induced THz generation for the study of the atmosphere of Mars and found that the overall THz yield near the surface of Mars is just a factor of 6 lower than on Earth. Comparable THz energy on the two planets is associated with underdense plasma on Earth (∼10% of neutrals) and full double ionization of carbon dioxide on Mars (∼200% of neutrals), the latter opening great perspective for THz remote sensing of trace gases in the Martian atmosphere.

O(3P) + CO2 scattering cross-sections at superthermal collision energies for planetary aeronomy

ABSTRACT We report new elastic and inelastic cross-sections for O(3P) + CO2 scattering at collision energies from 0.03 to 5 eV, of major importance to O escape from Mars, Venus, and CO2-rich atmospheres. The cross-sections were calculated from first principles using three newly constructed ab initio potential energy surfaces correlating to the lowest energy asymptote of the complex. The surfaces were restricted to a planar geometry with the CO2 molecule assumed to be in linear configuration fixed at equilibrium. Quantum-mechanical coupled-channel formalism with a large basis set was used to compute state-to-state integral and differential cross-sections for elastic and inelastic O(3P) + CO2 scattering between all pairs of rotational states of CO2 molecule. The elastic cross-sections are 35 per cent lower at 0.5 eV and more than 50 per cent lower at 4 + eV than values commonly used in studies of processes in upper and middle planetary atmospheres of Mars, Earth, Venus, and CO2-rich planets. Momentum transfer cross-sections, of interest for energy transport, were found to be proportionally lower than predicted by mass scaling.

Расчет периодов просвечивания венерианской атмосферы радиосигналом между двумя космическими аппаратами в задаче изучения её состава

The paper considers calculating the periods of radio signal transmission through the atmosphere of Venus between a small spacecraft placed in a limited orbit in the vicinity of the collinear libration point of the Sun-Venus system and a Venus orbiter. The problem arises in the framework of the project under discussion to study the atmosphere of Venus. The possibility of transfers of these spacecrafts to the required orbits under various initial conditions is also studied. The impulses required for transferring to the specified orbits at the selected initial state vector, the most suitable for solving this problem are calculated. The duration and the number of transmission periods depending on the location of one of the spacecrafts in a limited orbit in the vicinity of the libration point L1 or L2 of the Sun-Venus system are analyzed. The influence of the shape of the orbiter near-Venusian orbit on the character and duration of the periods of transmission through the atmosphere of Venus is investigated. It is concluded that the location of a small spacecraft in a limited orbit in the vicinity of the L1 libration point of the Sun-Venus system is more advantageous compared to L2 both in terms of the duration and the number of the transmission periods as well as terms of the necessary energy costs.

Venera-D: A Design of an Automatic Space Station for Venus Exploration

The paper focuses on a future mission to Venus, Venera-D, which is presently at the stage of defining the scientific objectives and shaping the preliminary mission architecture. The main scientific goals regarding the atmosphere, magnetosphere and internal structure of Venus are considered. The current configuration, baseline, and additional elements of the mission are described.

Программная реализация специального модуля для обеспечения исследования атмосферы Венеры с помощью двух космических аппаратов

Программная реализация специального модуля для обеспечения исследования атмосферы Венеры с помощью двух космических аппаратов

An experimental study of the mixing of CO2 and N2 under conditions found at the surface of Venus

Based on the only reliable temperature profile available in the deepest ∼10 km layer above Venus’ surface (obtained by the VeGa-2 landing probe), the mixing conditions of the main constituents of Venus’s atmosphere, CO2 and N2, have been questioned. In this work, we report the results of a series of experiments that were done in the GEER facility at Glenn Research Center to investigate the homogeneity of CO2/N2 gas mixtures at 100 bars and temperatures ranging from ∼296 K to ∼735 K. When the gas mixtures are initially well-mixed, separation of the two gases based on their molecular mass does not occur over the time scales observed; although, small systematic variations in composition remain to be fully interpreted. However, when N2 is injected on top of CO2 (layered fill), the very large density ratio makes it more difficult to mix the two chemical species. Timescales of mixing are of the order of 102 hours over the height of the test vessel (roughly 60 cm), and even longer when the gas mixture is at rest and only molecular diffusion is occurring. At room temperature, close to the critical point of the mixture, large pressure variations are obtained for the layered fill, as N2 slowly mixes into CO2. This can be explained by large density variations induced by the mixing. For conditions relevant to the near-surface atmosphere of Venus, separation of CO2 and N2 based on their molecular mass and due to physical properties of the gas mixture is not demonstrated, but cannot be firmly excluded either. This suggests that if the compositional vertical gradient deduced from the VeGa-2 temperature profile is to be trusted, it would most probably be due to some extrinsic processes (not related to gas properties, e.g. CO2 volcanic inputs) and large mixing time constants.

Gravitational signatures of atmospheric thermal tides on Venus

Thermal tides in the atmosphere of Venus transport a considerable amount of mass, on a wide range of spatial and temporal scales. We use simulated values of the surface atmospheric pressure distribution to estimate the time-varying gravitational potential, exterior to Venus. The expected amplitudes of gravitational signatures of thermal tides are below the errors from existing Magellan mission Doppler data, and have not yet been detected. However, they are large enough that we expect them to be well resolved by any of several measurement configurations for future Venus gravity missions.

Predicting the Formation of Sulfur-Based Brønsted Acids from the Reactions of SOx with H2O and H2S.

We have performed an extensive computational investigation of the potential energy surfaces for the reactions of SOx (x = 2 or 3) with H2S and H2O in the gas phase and in aqueous solution at the CCSD(T)/CBS level of theory plus a self-consistent reaction field approach. Formation of a gas-phase H2SO4 from the hydrolysis of SO3 at lower temperatures requires the presence of additional water molecules. When additional waters are introduced, the barrier for H2SO4 formation is significantly reduced, and a barrierless transition occurs with only three excess waters as well as in aqueous solution. In a mixture of H2O, H2S, and SO3, formation of H2S2O3 has a lower barrier in the gas phase than does the formation of H2SO4. In aqueous solution, no barrier is predicted, and both are likely to be formed. Introduction of an additional water to the SO3 + H2S reaction results in a decrease in barrier height, nearly identical to the ∼18 kcal/mol catalytic effect of the first additional water in SO3 hydrolysis, with the barrier for H2S2O3 formation disappearing altogether in aqueous solution. Formation of H2SO3 by the way of SO2 hydrolysis is unlikely. Excess waters reduce the barrier for SO2 hydrolysis; however, the overall endothermicity is increased as waters are added. The formation of H2S2O2 from SO2 and H2S via an isostructural pathway to SO2 hydrolysis is unlikely, with additional water molecules resulting in a small increase in the overall endothermicity and a catalytic effect smaller than that observed for the SO3 reactions. The results of this work have implications pertaining to the formation of H2SO4, H2S2O3, H2SO3, and H2S2O2 in the atmospheres of Earth and Venus. These results also question the existence of H2S2O2 as an intermediate in the Claus process.

OCS-CO2 line broadening coefficients and their temperature dependences for the Earth and Venus atmospheres

Theoretical carbon dioxide broadened line widths of carbonyl sulfide molecule are reported at the room temperature for wide ranges of rotational quantum numbers (0 ≤ J ≤ 100) requested by spectroscopic databases. To get the temperature-dependence exponents, computations with the room-temperature parameters’ values are repeated for various temperatures characteristic of the Earth and Venus atmospheres. The calculations are performed by a semi-empirical method which is based on the impact theory of broadening, and includes the correction factors whose parameters can be determined by fitting the broadening or shifting coefficients to the experimental data. This approach particularly suitable for active molecules with nonzero dipole moments, which needs only a few experimental data for model parameters fitting. Since the common power law for the temperature-dependence exponents is invalid for wide temperature ranges, two separate sets of temperature exponents are provided for Earth and Venus atmospheres applications.

Regenerative Solid Oxide Fuel Cells for Venus Interior Probe Energy Storage

A novel variable altitude Venus interior probe is currently under development that uses in-situ power and propulsion to lower a balloon down into Venus’s atmosphere, approximately 20 km from the surface, and then bring it back up above the clouds and hover at approximately 60 km from the surface. One of the biggest challenges is finding an energy storage solution that can withstand Venus’s harsh atmosphere. At 20 km the probe will experience temperatures close to 325°C, pressures around 20 atm, and an atmosphere composed of CO2, with trace amounts of sulfur containing compounds. Conventional energy storage technologies, like batteries, are not an option under these conditions. The only technology that can survive under these conditions are solid oxide fuel cells (SOFCs), which operate in a temperature range between 600 – 1000 °C. Fuel cells are devices that convert chemical energy, in this case from hydrogen and oxygen, into electricity with the only byproducts being heat and water. Solid oxide fuel cells can be run reversibly as an electrolyzer, taking the byproduct water and splitting it into hydrogen and oxygen that can then be used to run the fuel cell. A regenerative fuel cell system may therefore be built around a single SOFC stack. The goal is to run the SOFC to power the probe at 20 km and then reverse the SOFC to an electrolyzer when the probe is back above the clouds and use solar power to produce hydrogen and oxygen. The data presented in this work shows the successful operation of a regenerative SOFC. Figure 1A shows a SOFC that was run in H2/O2 as an electrolyzer. Figure 1B shows a SOFC run as a fuel cell in different conditions including H2/O2 (red line) and H2/Air at different flow rates (blue lines). The goal of this work is to pinpoint the exact conditions a SOFC would need to operate at in order to successfully store energy for an interior probe in the Venus atmosphere. This work was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration (NASA) and NASA’s Innovative Concepts (NIAC) Program: “Venus Interior Probe Using In-situ Power and Propulsion (VIP-INSPR). Figure 1

Global Structure of Thermal Tides in the Upper Cloud Layer of Venus Revealed by LIR on Board Akatsuki

AbstractLongwave Infrared Camera (LIR) on board Akatsuki first revealed the global structure of the thermal tides in the upper cloud layer of Venus. The data were acquired over three Venusian years, and the analysis was done over the areas from the equator to the midlatitudes in both hemispheres and over the whole local time. Thermal tides at two vertical levels were analyzed by comparing data at two different emission angles. Dynamical wave modes consisting of tides were identified; the diurnal tide consisted mainly of Rossby‐wave and gravity‐wave modes, while the semidiurnal tide predominantly consisted of a gravity‐wave mode. The revealed vertical structures were roughly consistent with the above wave modes, but some discrepancy remained if the waves were supposed to be monochromatic. In turn, the heating profile that excites the tidal waves can be constrained to match this discrepancy, which would greatly advance the understanding of the Venusian atmosphere.

Cosmic dust fluxes in the atmospheres of Earth, Mars, and Venus

The ablation of cosmic dust injects a range of metals into planetary upper atmospheres. In addition, dust particles which survive atmospheric entry can be an important source of organic material at a planetary surface. In this study the contribution of metals and organics from three cosmic dust sources – Jupiter-Family comets (JFCs), the Asteroid belt (AST), and Halley-Type comets (HTCs) – to the atmospheres of Earth, Mars and Venus is estimated by combining a Chemical Ablation Model (CABMOD) with a Zodiacal Cloud Model (ZoDy). ZoDy provides the mass, velocity, and radiant distributions for JFC, AST, and HTC particles. JFCs are shown to be the main mass contributor in all three atmospheres (68% for Venus, 70% Earth, and 52% for Mars), providing a total input mass for Venus, Earth and Mars of 31 ± 18 t d−1, 28 ± 16 t d−1 and 2 ± 1 t d−1, respectively. The mass contribution of AST particles increases with heliocentric distance (6% for Venus, 9% for Earth, and 14% for Mars). A novel multiphase treatment in CABMOD, tested experimentally in a Meteoric Ablation Simulator, is implemented to quantify atmospheric ablation from both the silicate melt and Fe-Ni metal domains. The ratio of Fe:Ni ablation fluxes at Earth, Mars and Venus are predicted to be close to their CI chondritic ratio of 18, in agreement with mass spectrometric measurements of Fe+:Ni+ = 20−8+13 in the terrestrial ionosphere. In contrast, lidar measurements of the neutral atoms at Earth indicate Fe:Ni = 38 ± 11, and observations by the Neutral Gas and Ion Mass Spectrometer on the MAVEN spacecraft at Mars indicate Fe+:Ni+ = 43−10+13. Given the slower average entry velocity of cosmic dust particles at Mars, the accretion rate of unmelted particles in Mars represents 60% of the total input mass, of which a significant fraction of the total unmelted mass (22%) does not reach an organic pyrolysis temperature (~900 K), leading to a flux of intact carbon of 14 kg d−1. This is significantly smaller than previous estimates.

Исследование точек либрации в системе Солнце – Венера с целью формирования орбитальной системы для изучения атмосферы Венеры

Исследование точек либрации в системе Солнце – Венера с целью формирования орбитальной системы для изучения атмосферы Венеры

The Physical Origin of the Venus Low Atmosphere Chemical Gradient

Abstract Venus shares many similarities with the Earth, but concomitantly, some of its features are extremely original. This is especially true for its atmosphere, where high pressures and temperatures are found at the ground level. In these conditions, carbon dioxide, the main component of Venus’ atmosphere, is a supercritical fluid. The analysis of VeGa-2 probe data has revealed the high instability of the region located in the last few kilometers above the ground level. Recent works have suggested an explanation based on the existence of a vertical gradient of molecular nitrogen abundances, around 5 ppm per meter. Our goal was then to identify which physical processes could lead to the establishment of this intriguing nitrogen gradient, in the deep atmosphere of Venus. Using an appropriate equation of state for the binary mixture CO2–N2 under supercritical conditions, and also molecular dynamics simulations, we have investigated the separation processes of N2 and CO2 in the Venusian context. Our results show that molecular diffusion is strongly inefficient, and potential phase separation is an unlikely mechanism. We have compared the quantity of CO2 required to form the proposed gradient with what could be released by a diffuse degassing from a low volcanic activity. The needed fluxes of CO2 are not so different from what can be measured over some terrestrial volcanic systems, suggesting a similar effect at work on Venus.

Mesoscale modeling of Venus' bow-shape waves

The Akatsuki instrument LIR measured an unprecedented wave feature at the top of Venusian cloud layer. Stationary bow-shape waves of thousands of kilometers large lasting several Earth days have been observed over the main equatorial mountains. Here we use for the first time a mesoscale model of the Venus's atmosphere with high-resolution topography and fully coupled interactive radiative transfer computations. Mountain waves resolved by the model form large-scale bow shape waves with an amplitude of about 1.5 K and a size up to several decades of latitude similar to the ones measured by the Akatsuki spacecraft. The maximum amplitude of the waves appears in the afternoon due to an increase of the near-surface stability. Propagating vertically the waves encounter two regions of low static stability, the mixed layer between approximately 18 and 30 km and the convective layer between 50 and 55 km. Some part of the wave energy can pass through these regions via wave tunneling. These two layers act as wave filter, especially the deep atmosphere layer. The encounter with these layers generates trapped lee waves propagating horizontally. No stationary waves is resolved at cloud top over the polar regions because of strong circumpolar transient waves, and a thicker deep atmosphere mixed layer that filters most of the mountain waves.

Venus Atmospheric Composition in situ Data: A Compilation.

The Venus atmosphere is of significant interest yet only rudimentary solid data has been gathered about its composition and chemistry. These measurements are scattered through time and place and are limited by parameters such as resolution and error margins as well as reinterpretations. This paper presents an extensive compilation of published in situ data for the atmospheric composition of Venus. It also includes remotely gathered measurements and some extrapolated and modeled data for the lower atmosphere. The composition tables are divided in four categories: noble gases, reactive gases, noble and non-noble isotopes. These tables were first presented in 2016 within the scientific heritage appendix of the Deep Atmosphere Venus Investigation of Noble gases, Chemistry, and Imaging (DAVINCI) mission proposal. These tables provide respective measurements, error margins, techniques, altitudes, instruments, mission and references. The objective of this paper is to provide a simple, comprehensive list of available measurements to date; in particular, the in situ data, to serve as a quick overall Venus atmosphere data reference.

Response of QIT-MS to Noble Gas Isotopic Ratios in a Simulated Venus Flyby

The primary objective of the present study is to investigate the science return of future Venus atmosphere probe mission concepts using the Quadrupole Ion Trap (QIT) Mass Spectrometer (MS) Instrument (QIT-MS-I). We demonstrate the use of Monte-Carlo simulations in determining the optimal ion trapping conditions and focus the analysis on retrieving isotope ratios of noble gases in the model sample of the Venus atmosphere. Sampling takes place at a constant velocity of ~10 km/s between 112–110 km altitude and involves the use of getter pumps to remove all chemically-active species, retaining inert noble gases. The enriched sample is leaked into passively pumped vacuum chamber where it is analyzed by the QIT-MS sensor (QIT-MS-S) for 40 minutes. The simulated mass spectrum, as recorded by the QIT-MS-S, is deconvoluted using random walk algorithm to reveal relative abundances of noble gas isotopes. The required precision and accuracy of the deconvolution method is benchmarked against the a priori known model composition of the atmospheric sample.

Revisiting the cosmic-ray induced Venusian ionization with the Atmospheric Radiation Interaction Simulator (AtRIS)

Context.Cosmic ray bombardment represents a major source of ionization in planetary atmospheres. The higher the energy of the primary cosmic ray particles, the deeper they can penetrate into the atmosphere. In addition, incident high energy cosmic ray particles induce extensive secondary particle cascades (“air showers”) that can contain up to several billion secondary particles per incoming primary particle. To quantify cosmic ray-induced effects on planetary atmospheres it is therefore important to accurately model the entire secondary particle cascade. This is particularly important in thick planetary atmospheres where the secondary particle cascades can develop extensively before being absorbed by the surface.Aims.Inside the Venusian atmosphere, cosmic rays are the dominant driver for the ionization below an altitude of ~100 km. In this work we revisit the numerical modeling of the galactic and solar cosmic-ray induced atmospheric ionization for cosmic ray ions from Hydrogen (Z= 1) to Nickel (Z= 28) and investigate the influence of strong solar energetic particle events inside the Venusian atmosphere.Methods.The Atmospheric Radiation Interaction Simulator (AtRIS), a newly developed simulation code to model the interaction of the near-(exo)planet particle and radiation field with the (exo)planetary atmosphere, was used to revisit the modeling of the altitude-dependent Venusian atmospheric ionization. Thereby, spherical geometry, the newest version of Geant4 (10.5) as well as the newest Geant4-based hadronic and electromagnetic interaction models were utilized.Results.Based on our new model approach we show that previous studies may have underestimated the galactic cosmic ray-induced atmospheric ion pair production by, amongst others, underestimating the influence of galactic cosmic ray protons above 1 TeV/nuc. Furthermore, we study the influence of 71 exceptionally strong solar particle events that were measured as Ground Level Enhancements at the Earth’s surface, and show a detailed analysis of the impact of such strong events on the Venusian ionization.

High-temperature electronic devices enabled by hBN-encapsulated graphene

Numerous applications call for electronics capable of operation at high temperatures where conventional Si-based electrical devices fail. In this work, we show that graphene-based devices are capable of performing in an extended temperature range up to 500 °C without noticeable thermally induced degradation when encapsulated by hexagonal boron nitride (hBN). The performance of these devices near the neutrality point is dominated by thermal excitations at elevated temperatures. Non-linearity pronounced in electric field-mediated resistance of the aligned graphene/hBN allowed us to realize heterodyne signal mixing at temperatures comparable to that of the Venus atmosphere (∼460 °C).