Update of the Venus density and temperature profiles at high altitude measured by SOIR on board Venus Express

Mahieux, A.; Vandaele, Ann Carine; Bougher, S. W.; Drummond, R.; Robert, Séverine; Wilquet, V.; Chamberlain, Sarah; Piccialli, Arianna; Montmessin, Franck; Tellmann, S.; Pätzold, M.; Häusler, B.; Bertaux, Jean-Loup

doi:10.1016/j.pss.2015.02.002

Cited by 65 publications

(101 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Regarding temperatures from groundbased observations (Krasnopolsky 2014) a proper comparison is not possible because of the different vertical layer sensed. And although solar occultation with SOIR show larger error bars (Mahieux et al 2015a), and their vertical weighting functions are also different, their temperatures agree well with the tendency of our values towards the terminator. On the other hand, the thermal gradient between the subsolar and antisolar meridians is of crucial importance to get an accurate evaluation of the SS-AS circulation.…”

Section: Resultssupporting

confidence: 87%

“…Atmospheric temperature at the lower thermosphere of Venus: comparison and time evolution. A) and B) show our temperatures at the subsolar meridian and the equator compared with results from CO NLTE limb spectra (Gilli et al 2015;Krasnopolsky 2014), solar occultation with SOIR/VEx (Mahieux et al 2015a), and numerical VTGCM (Brecht & Bougher 2012); C) subsolar (red) and antisolar temperatures (blue) inferred with CO 2 NLTE spectra taken by VEx/VIRTIS-H (this work) and with stellar occultation using SPICAV (Piccialli et al 2015). The difference between subsolar and antisolar temperatures are shown in green.…”

Section: Discussionmentioning

confidence: 99%

“…Although sparse in the horizontal (lat, local time), dayside temperatures between 100 and 150 km have been obtained from limb observations of the infrared non-local thermodynamic equilibrium (NLTE) emissions of CO at 4.7 µm (Gilli et al 2015). A few other observations available in the UMLT are dispersed (Sonnabend et al 2012;Krasnopolsky 2014) or focused at selected local times (Mahieux et al 2015a). Hence, the temperatures in the upper mesosphere and lower mesosphere and, in particular, their horizontal distribution have not been properly issued to date.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3μm

Peralta

López‐Valverde

Gilli

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

In this work, we analysed nadir observations of atmospheric infrared emissions carried out by VIRTIS, a high-resolution spectrometer on board the European spacecraft Venus Express. We focused on the ro-vibrational band of CO 2 at 4.3 µm on the dayside, whose fluorescence originates in the Venus upper mesosphere and above. This is the first time that a systematic sounding of these non-local thermodynamic equilibrium (NLTE) emissions has been carried out in Venus using this geometry. As many as 143,218 spectra have been analysed on the dayside during the period 14/05/2006 to 14/09/2009. We designed an inversion method to obtain the atmospheric temperature from these non-thermal observations, including a NLTE line-by-line forward model and a pre-computed set of spectra for a set of thermal structures and illumination conditions. Our measurements sound a broad region of the upper mesosphere and lower thermosphere of Venus ranging from 10 −2 -10 −5 mb (which in the Venus International Reference Atmosphere, VIRA, is approximately 100-150 km during the daytime) and show a maximum around 195 ± 10 K in the subsolar region, decreasing with latitude and local time towards the terminator. This is in qualitative agreement with predictions by a Venus Thermospheric General Circulation Model (VTGCM) after a proper averaging of altitudes for meaningful comparisons, although our temperatures are colder than the model by about 25 K throughout. We estimate a thermal gradient of about 35 K between the subsolar and antisolar points when comparing our data with nightside temperatures measured at similar altitudes by SPICAV, another instrument on Venus Express (VEx). Our data show a stable temperature structure through five years of measurements, but we also found episodes of strong heating/cooling to occur in the subsolar region of less than two days.

show abstract

Section: Resultssupporting

confidence: 87%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3μm

Peralta

López‐Valverde

Gilli

et al. 2015

A&A

Self Cite

View full text Add to dashboard Cite

show abstract

“…The corresponding temperature profiles (right hand-side panel, Fig. 11) show a large variability in the entire altitude range probed by SOIR (Mahieux et al 2015a). However, a systematic structure is always observed, with a very cold layer around 120 km (10 −5 mb, temperatures around 100 K) surrounded by two warmer layers at 100 km (10 −2 mb, temperatures around 250 K) and 150 km (10 −7 mb, temperatures around 220 K).…”

Section: Temperature Profiles From Solar Occultations In the Infraredmentioning

confidence: 96%

“…In contrast, the errors in the first method arise from ray tracing and deviations from the assumed homopause level in the retrieval procedure for a given profile. The study compares the mean value of the rotational temperature profiles with the general structure of the kinetic temperature profiles derived using the hydrostatic equilibrium (Mahieux et al 2015a), within the very cold layer at ∼ 130 km, see Fig. 14. In addition, no rotational non-LTE emissions have been observed.…”

Section: Temperature Profiles From Solar Occultations In the Infraredmentioning

confidence: 99%

Venus Atmospheric Thermal Structure and Radiative Balance

et al. 2018

View full text Add to dashboard Cite

From the discovery that Venus has an atmosphere during the 1761 transit by M. Lomonosov to the current exploration of the planet by the Akatsuki orbiter, we continue to learn about the planet's extreme climate and weather. This chapter attempts to provide a comprehensive but by no means exhaustive review of the results of the atmospheric thermal structure and radiative balance since the earlier works published in Venus and Venus II books from recent spacecraft and Earth based investigations and summarizes the gaps in [1411][1412][1413][1414] 1986). Thus, most of the new information about the atmospheric thermal structure has come from different remote sensing (Earth based and spacecraft) techniques using occultations (solar infrared, stellar ultraviolet and orbiter radio occultations), spectroscopy and microwave, short wave and thermal infrared emissions. The results are restricted to altitudes higher than about 40 km, except for one investigation of the near surface static stability inferred by Meadows and Crisp (J. Geophys. Res. 101:4595-4622, 1996) from 1 μm observations from Earth. Little information about the lower atmospheric structure is possible below about 40 km altitude from radio occultations due to large bending angles. The gaps in our knowledge include spectral albedo variations over time, vertical variation of the bulk composition of the atmosphere (mean molecular weight), the identity, properties and abundances of absorbers of incident solar radiation in the clouds. The causes of opacity variations in the nightside cloud cover and vertical gradients in the deep atmosphere bulk composition and its impact on static stability are also in need of critical studies. The knowledge gaps and questions about Venus and its atmosphere provide the incentive for obtaining the necessary measurements to understand the planet, which can provide some clues to learn about terrestrial exoplanets.

show abstract

The phase of water ice which forms in cold clouds in the mesospheres of Mars, Venus and Earth

Mangan

Plane

Murray

2020

Preprint

View full text Add to dashboard Cite

Water ice clouds can form in the coldest regions of rarefied planetary upper atmospheres, where particles grow through deposition from the vapor phase. Despite the very low partial pressures of water in the upper atmospheres of Venus, Earth, and Mars, the temperatures can be low enough (∼<150 K, depending on the planet) to lead to large supersaturations and the formation of ice particles. At these temperatures multiple metastable forms of ice can exist, but the phases that can form remain poorly defined. In this study, we focus on understanding the phase of ice that forms in this class of very cold clouds which exist in the upper atmospheres of three of the terrestrial planets in the solar system. In Earth's upper mesosphere (80-90 km), nanoparticles composed primarily of water ice form between 100 and 150 K, producing clouds known as Polar Mesospheric Clouds (PMCs) or noctilucent clouds (NLCs) (Hervig et al., 2001;Rapp & Thomas, 2006;Thomas, 1991). In the Martian atmosphere, water ice clouds have also been observed planet wide at altitudes up to 90 km where temperatures can drop to <120 K (Fedorova et al., 2020;Forget et al., 2009;Vincendon et al., 2011). In addition, water ice particles may serve as seeds for CO 2 ice particles in the Martian mesosphere (Plane et al., 2018). On Venus, the possibility of water

show abstract

Update of the Venus density and temperature profiles at high altitude measured by SOIR on board Venus Express

Cited by 65 publications

References 33 publications

Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3μm

Dayside temperatures in the Venus upper atmosphere from Venus Express/VIRTIS nadir measurements at 4.3μm

Venus Atmospheric Thermal Structure and Radiative Balance

The phase of water ice which forms in cold clouds in the mesospheres of Mars, Venus and Earth

Contact Info

Product

Resources

About