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Recent Hotspot Volcanism on Venus from VIRTIS Emissivity Data
Drossart, Pierre; Piccioni, Giuseppe; Helbert, Joern +5 more
The questions of whether Venus is geologically active and how the planet has resurfaced over the past billion years have major implications for interior dynamics and climate change. Nine “hotspots”—areas analogous to Hawaii, with volcanism, broad topographic rises, and large positive gravity anomalies suggesting mantle plumes at depth—have been id…
Superrotation of Venus' atmosphere analyzed with a full general circulation model
Lebonnois, Sébastien; Hourdin, Frédéric; Eymet, Vincent +3 more
A general circulation model (GCM) has been developed for the Venus atmosphere, from the surface up to 100 km altitude, based on the GCM developed for Earth at our laboratory. Key features of this new GCM include topography, diurnal cycle, dependence of the specific heat on temperature, and a consistent radiative transfer module based on net exchan…
Hemispheric asymmetry of the magnetic field wrapping pattern in the Venusian magnetotail
Kallio, E.; Luhmann, J. G.; Russell, C. T. +7 more
We examine statistically the magnetic field in the Venusian magnetotail which is formed by the draping of interplanetary magnetic field lines. Although the near-planet and distant magnetotail regions have been sampled by the various missions to Venus and the general magnetic features of the distant magnetotail are well established, the near wake r…
Photolysis of sulphuric acid as the source of sulphur oxides in the mesosphere of Venus
Montmessin, Franck; Bertaux, Jean-Loup; Zhang, Xi +3 more
The sulphur cycle plays fundamental roles in the chemistry and climate of Venus. Thermodynamic equilibrium chemistry at the surface of Venus favours the production of carbonyl sulphide and to a lesser extent sulphur dioxide. These gases are transported to the middle atmosphere by the Hadley circulation cell. Above the cloud top, a sulphur oxidatio…
Spatially-resolved high-resolution spectroscopy of Venus 2. Variations of HDO, OCS, and SO 2 at the cloud tops
Krasnopolsky, Vladimir A.
While CO, HCl, and HF, that were considered in the first part of this work, have distinct absorption lines in high-resolution spectra and were detected four decades ago, the lines of HDO, OCS, and SO 2 are either very weak or blended by the telluric lines and have not been observed previously by ground-based infrared spectroscopy at the…
Venus night airglow: Ground-based detection of OH, observations of O 2 emissions, and photochemical model
Krasnopolsky, Vladimir A.
Venus nightglow was observed at NASA IRTF using a high-resolution long-slit spectrograph CSHELL at LT = 21:30 and 4:00 on Venus. Variations of the O 2 airglow at 1.27 µm and its rotational temperature are extracted from the observed spectra. The mean O 2 nightglow is 0.57 MR at 21:30 at 35°S-35°N, and the temperature in…
A general circulation model ensemble study of the atmospheric circulation of Venus
Lee, C.; Richardson, M. I.
The response of three numerical model dynamical cores to Venus-like forcing and friction is described in this paper. Each dynamical core simulates a super-rotating atmospheric circulation with equatorial winds of 35 ± 10 m/s, maintained by horizontally propagating eddies leaving the equatorial region and inducing a momentum convergence there. We d…
Thermal structure of Venusian nighttime mesosphere as observed by VIRTIS-Venus Express
Drossart, P.; Piccioni, G.; Lebonnois, S. +5 more
The mapping IR channel of the Visual and Infrared Thermal Imaging Spectrometer (VIRTIS-M) on board the Venus Express spacecraft observes the CO2 band at 4.3 µm at a spectral resolution adequate to retrieve the atmospheric temperature profiles in the 65-96 km altitude range. Observations acquired in the period June 2006 to July 200…
Prediction of uncertainties in atmospheric properties measured by radio occultation experiments
Withers, Paul
Refraction due to gradients in ionospheric electron density, Ne, and neutral number density, nn, can shift the frequency of radio signals propagating through a planetary atmosphere. Radio occultation experiments measure time series of these frequency shifts, from which Ne and nn can be determined. Major …
Densities and temperatures in the Venus mesosphere and lower thermosphere retrieved from SOIR on board Venus Express: Retrieval technique
Vandaele, A. C.; Robert, S.; Wilquet, V. +5 more
The SOIR instrument, flying on board Venus Express, operates in the infrared spectral domain and uses the solar occultation technique to determine the vertical profiles of several key constituents of the Venus atmosphere. The retrieval algorithm is based on the optimal estimation method, and solves the problem simultaneously on all spectra belongi…