Circulation of Venusian Atmosphere at 90–110 km Based on Apparent Motions of the O<sub>2</sub> 1.27 μm Nightglow From VIRTIS‐M (Venus Express) Data

Gorinov, Dmitry; Khatuntsev, I.; Zasova, L.; Turin, Alexander; Piccioni, G.

doi:10.1002/2017gl076380

Cited by 19 publications

(19 citation statements)

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“…The higher the altitude, the shorter the radiative relaxation time and the greater the day-night temperature difference. Such a strong thermal forcing can induce subsolar-to-antisolar (SS-AS) circulation instead of superrotation (Seiff 1982;Gorinov et al 2018). On the other hand, a strong thermal forcing can induce eddy momentum fluxes via generation of solar-locked waves (tides), which potentially induces equatorial superrotation (Takagi and Matsuda 2007;Showman and Polvani 2011); evaluation of competing processes is crucial.…”

Section: Dynamical Structure and Eddy Momentum Transportmentioning

confidence: 99%

“…This method gives access to zonal wind maps in the 45-95 km altitude range. Gorinov et al (2018) used tracking of O 2 (a1 g) 1.27 µm nightglow from VIRTIS onboard Venus Express, which corresponds to altitudes of 90-110 km, the region in between the superrotation and the SS-AS circulation. Two opposite flows from the terminator to midnight were observed.…”

Section: Observations Of Venus's Atmospheric Circulationmentioning

confidence: 99%

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Superrotation in Planetary Atmospheres

et al. 2020

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Superrotation is a dynamical regime where the atmosphere circulates around the planet in the direction of planetary rotation with excess angular momentum in the equatorial region. Superrotation is known to exist in the atmospheres of Venus, Titan, Jupiter, and Saturn in the solar system. Some of the exoplanets also exhibit superrotation. Our understanding of superrotation in a framework of circulation regimes of the atmospheres of terrestrial planets is in progress thanks to the development of numerical models; a global instability involving planetary-scale waves seems to play a key role, and the dynamical state depends on the Rossby number, a measure of the relative importance of the inertial and Coriolis forces, and the thermal inertia of the atmosphere. Recent general circulation models of Venus's and Titan's atmospheres demonstrated the importance of horizontal waves in the angular momentum transport in these atmospheres and also an additional contribution of thermal tides in Venus's atmosphere. The atmospheres of Jupiter and Saturn also exhibit strong superrotation. Recent gravity data suggests that these superrotational flows extend deep into the planet, yet currently no single mechanism has been identified as driving this superrotation. Moreover, atmospheric circulation models of tidally locked, strongly Understanding the Diversity of Planetary Atmospheres Edited by François Forget,

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Section: Dynamical Structure and Eddy Momentum Transportmentioning

confidence: 99%

Section: Observations Of Venus's Atmospheric Circulationmentioning

confidence: 99%

Superrotation in Planetary Atmospheres

et al. 2020

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“…Gravity waves with vertical wavelength of 10-14 km and horizontal scale of 100-1,000 km were identified at the mesopause (~100 km) by Altieri et al (2014) from the modeling of vertical profiles of the O 2 1.27 μm nightglow emission measured by VEx's Visible and Infrared Thermal Imaging Spectrometer in low-resolution mapping mode at the limb of the planet (Drossart et al, 2007). The influence of surface topography on the atmospheric circulation at 90-100 km was also found by Gorinov et al (2018) who analyzed apparent motions of the nightglow features. They were typically observed above the mountains, sometimes following the highland's contours or shifted and rotated by a few tens of degrees.…”

Section: 1029/2018je005620mentioning

confidence: 87%

Solar‐Related Variations of the Cloud Top Circulation Above Aphrodite Terra From VMC/Venus Express Wind Fields

et al. 2019

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Winds derived by a digital tracking technique from ultraviolet (365 nm) images captured by the Venus Monitoring Camera (VMC) onboard the Venus Express spacecraft from 2006 to 2013 were used to study the atmospheric circulation at cloud top level (70 ± 2 km). This data set allows variations of the wind speed with both latitude and longitude to be studied and establishes their correlation with surface topography as well as local time dependence. Both zonal and meridional wind components show some correlation with topography. The minimum zonal wind speed was found at noon above Ovda Regio (10°S, 93°E), the highest region of Aphrodite Terra, one of the largest highlands in the equatorial region. The area of slow zonal wind extends to at least 30°S and shifts in the direction of superrotation in the afternoon and with increasing latitude (poleward). The observed deceleration of cloud top wind was recently attributed to the interaction of the gravity (mountain) waves generated by Aphrodite Terra with the atmospheric circulation. The present study was performed for different local time over the mountainous longitudes. The deceleration pattern in the zonal wind field is mainly conserved within a few hours around noon. Systematic longitude shift is observed in the afternoon in the direction of the evening terminator. Another area of perturbation of both zonal and meridional wind components is observed in the equatorial region around LT = 13–14 hr and may be explained by the solar tide.

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“…Several observations support the presence of SS-AS flows at the altitudes of ~ 95-120 km (Gérard et al 2017). The SS-AS flow at ~ 97.4 ± 2.5 km was inferred from nightglow tracking of O 2 observed by the Visible and Infrared Thermal Imaging Spectrometer (VIRTIS) aboard VEX (Drossart et al 2007;Gorinov et al 2018). The Doppler wind velocities at the altitudes at ~ 95-115 km were also derived from the CO LTE (local thermodynamic equilibrium) absorption lines observed in the sub-millimeter range (e.g., Lellouch et al 2008;Moullet et al 2012;Clancy et al 2012bClancy et al , 2015.…”

Section: Introductionmentioning

confidence: 87%

Evaluation of a method to retrieve temperature and wind velocity profiles of the Venusian nightside mesosphere from mid-infrared CO2 absorption line observed by heterodyne spectroscopy

Takami

Nakagawa

Sagawa

et al. 2020

Earth Planets Space

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We evaluated a method for retrieving vertical temperature and Doppler wind velocity profiles of the Venusian nightside mesosphere from the CO 2 absorption line resolved by mid-infrared heterodyne spectroscopy. The achievable sensitive altitude and retrieval accuracy were derived with multiple model spectra generated from various temperature and wind velocity profiles with several noise levels. The temperature profiles were retrieved at altitudes of 70-100 km with a vertical resolution of 5 km and a retrieval accuracy of ± 15 K. The wind velocity was also retrieved at an altitude of approximately 85 km with a vertical resolution of 10 km and a retrieval accuracy of ± 25-50 m/s. In addition, we studied an event and applied our method to spectra obtained by the HIPWAC instrument attached to the NASA/IRTF 3-m telescope on May 19-22, 2012. Retrieved wind velocities in a latitude of 33° S at 3:00 LT were interpreted as subsolar-to-antisolar (SS-AS) flows at altitudes of 84 ± 6 km and 94 ± 7 km, and they were stronger than expected. This result suggested that the transition between the retrograde superrotational zonal (RSZ) wind and SS-AS flow may occur at altitudes below 90 km which previously was predicted to be the transition region. This work provides a basis for our analysis of further observations obtained by a mid-infrared heterodyne spectrometer MILAHI attached to the Tohoku University 60-cm telescope at Haleakalā, Hawaii.

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Circulation of Venusian Atmosphere at 90–110 km Based on Apparent Motions of the O₂ 1.27 μm Nightglow From VIRTIS‐M (Venus Express) Data

Cited by 19 publications

References 34 publications

Superrotation in Planetary Atmospheres

Superrotation in Planetary Atmospheres

Solar‐Related Variations of the Cloud Top Circulation Above Aphrodite Terra From VMC/Venus Express Wind Fields

Evaluation of a method to retrieve temperature and wind velocity profiles of the Venusian nightside mesosphere from mid-infrared CO2 absorption line observed by heterodyne spectroscopy

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Circulation of Venusian Atmosphere at 90–110 km Based on Apparent Motions of the O2 1.27 μm Nightglow From VIRTIS‐M (Venus Express) Data

Cited by 19 publications

References 34 publications

Superrotation in Planetary Atmospheres

Superrotation in Planetary Atmospheres

Solar‐Related Variations of the Cloud Top Circulation Above Aphrodite Terra From VMC/Venus Express Wind Fields

Evaluation of a method to retrieve temperature and wind velocity profiles of the Venusian nightside mesosphere from mid-infrared CO2 absorption line observed by heterodyne spectroscopy

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Circulation of Venusian Atmosphere at 90–110 km Based on Apparent Motions of the O₂ 1.27 μm Nightglow From VIRTIS‐M (Venus Express) Data