Overview of VEGA Venus Balloon in Situ Meteorological Measurements

Sagdeev, R. Z.; Linkin, V. M.; Kerzhanovich, V. V.; Lipatov, A. N.; Shurupov, A. A.; Blamont, J. É.; Crisp, David; Ingersoll, Andrew P.; Elson, L. S.; Preston, R. A.; Hildebrand, C. E.; Ragent, B.; Seiff, A.; Young, Richard E.; Petit, Gérard; Boloh, L.; Alexandrov, Yu. N.; Armand, N. A.; Bakitko, R. V.; Selivanov, A. S.

doi:10.1126/science.231.4744.1411

Cited by 117 publications

(44 citation statements)

References 7 publications

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“…Each gondola was equipped with a photodiode light gauge, including an electronic high-pass filter to detect flashes. No flash detections were reported: Sagdeev et al (1986) notes that the intermediatebrightness flash counter on VEGA 2 did increment once, indicating a possible flash, but the measurement is suspicious because it was made near the terminator (where varying cloud-top altitudes could cause strong changes in ambient illumination) and that the lower-level threshold counter should also have incremented but did not. The VEGA data have recently been restored and made available for the NASA Planetary Data System (PDS)- Lorenz et al (2018); it may be noted that the VEGA-2 lander pressure-temperature profile therein is the only high-quality in situ atmospheric dataset that reaches all the way to the surface of Venus.…”

Section: Vega Balloonmentioning

confidence: 99%

Lightning detection on Venus: a critical review

Lorenz

2018

Prog Earth Planet Sci

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Claimed detections and nondetections of lightning and related electromagnetic emissions on Venus are qualitatively contradictory. Here, motivated by the commencement of observations by the Akatsuki spacecraft and by studies of future missions, we critically review spacecraft and ground-based observations of the past 40 years, in an attempt to reconcile the discordant reports with a minimal number of assumptions. These include invoking alternative interpretations of individual reports, guided by sensitivity thresholds, controls, and other objective benchmarks of observation integrity. The most compelling evidence is in fact the first, the very low frequency (VLF) radio emissions recorded beneath the clouds by all four of the Veneras 11-13 landers, and those data are re-examined closely, finding power-law amplitude characteristics and substantial differences between the different profiles. It is concluded that some kind of frequent electrical activity is supported by the preponderance of observations, but optical emissions are not consistent with terrestrial levels of activity. Venus' activity may, like Earth's, have strong temporal and/or spatial variability, which coupled with the relatively short accumulated observation time for optical measurements, can lead to qualitative discrepancies between observation reports. We note a number of previously unconsidered observations and outline some considerations for future observations.

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Section: Vega Balloonmentioning

confidence: 99%

Lightning detection on Venus: a critical review

Lorenz

2018

Prog Earth Planet Sci

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“…Given the large thermal inertia, the temperature differences in the near surface atmosphere are expected to be small in the deep atmosphere (Stone 1975). The two VeGa balloons sampled different portions of the atmosphere at ∼ 54 km two days apart while moving in nearly zonal trajectories at 5°N and 6°S latitudes but showed a consistent 6 K difference in temperatures (Sagdeev et al 1986). Mueller et al (2018) suggest regional variations in surface temperatures from analysis of near infrared observations from Venus Express.…”

Section: Introductionmentioning

confidence: 99%

Venus Atmospheric Thermal Structure and Radiative Balance

et al. 2018

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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.

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“…Small-scale atmospheric structures indicative of internal gravity waves were observed in temperature profiles (Hinson and Jenkins, 1995) and in cloud images Peralta et al, 2008). Oscillating vertical winds encountered by Vega balloons over highlands are attribute to orographically-excited gravity waves (Sagdeev et al, 1986); orographic waves, however, should transport eastward momentum upward and decelerate the super-rotation.…”

Section: Super-rotationmentioning

confidence: 99%

“…The Pioneer Venus orbiter and entry probes of U.S., which were launched in 1978, also provided plenty of new information on the atmosphere and the surface (Colin, 1980). The Vega balloons were dropped into the cloud layer of Venus by the Soviet Union and France in 1985 and observed meso-scale cloud processes and horizontal advection over 46 hours (Sagdeev et al, 1986). The U.S. probe Magellan, which took off for Venus in 1989, radar-mapped the Venusian surface precisely (Saunders et al, 1992).…”

Section: Introductionmentioning

confidence: 99%

Overview of Venus orbiter, Akatsuki

et al. 2011

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The Akatsuki spacecraft of Japan was launched on May 21, 2010. The spacecraft planned to enter a Venusencircling near-equatorial orbit in December 7, 2010; however, the Venus orbit insertion maneuver has failed, and at present the spacecraft is orbiting the Sun. There is a possibility of conducting an orbit insertion maneuver again several years later. The main goal of the mission is to understand the Venusian atmospheric dynamics and cloud physics, with the explorations of the ground surface and the interplanetary dust also being the themes. The angular motion of the spacecraft is roughly synchronized with the zonal flow near the cloud base for roughly 20 hours centered at the apoapsis. Seen from this portion of the orbit, cloud features below the spacecraft continue to be observed over 20 hours, and thus the precise determination of atmospheric motions is possible. The onboard science instruments sense multiple height levels of the atmosphere to model the three-dimensional structure and dynamics. The lower clouds, the lower atmosphere and the surface are imaged by utilizing nearinfrared windows. The cloud top structure is mapped by using scattered ultraviolet radiation and thermal infrared radiation. Lightning discharge is searched for by high speed sampling of lightning flashes. Night airglow is observed at visible wavelengths. Radio occultation complements the imaging observations principally by determining the vertical temperature structure.

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Overview of VEGA Venus Balloon in Situ Meteorological Measurements

Cited by 117 publications

References 7 publications

Lightning detection on Venus: a critical review

Lightning detection on Venus: a critical review

Venus Atmospheric Thermal Structure and Radiative Balance

Overview of Venus orbiter, Akatsuki

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