VEGA Balloon meteorological measurements

Ground-Based Near-Infrared Imaging Observations of Venus During the Galileo Encounter

“…We reduced the effects of scattered light from the bright sunlit crescent by subtracting out-of-band images (taken near 2.1 pm, where the night side emits little radiation) from each in-band (2.36 pm) image. (19,20). Both balloons floated within the middle cloud at low latitudes, but they were separated by about 135" of longitude.…”

On the small-scale turbulence parameters in the atmosphere of venus and their use in the global circulation models

“…This is also indicated by the presence of buoyancy waves (BW) in the whole troposphere of Venus, which was detected in the experiments on the Vega 1 and Vega 2 balloons. They showed that the BW connected fluctuations of the wind velocity at an altitude of about 50 km are stronger above mountain regions than above plains Crisp et al, 1990). The presence of buoyancy waves is confirmed by calcula tions which showed that they originate when the wind flows along the planetary surface following its relief, and propagates upward; at an altitude of 50 km, their intensity is close to that measured from the Vega bal loons (Young et al, 1987;1994;Izakov, 2010b).…”

“…On Venus, this statement was confirmed by the data from the Vega 1 and Vega 2 balloons; they showed the presence of buoyancy waves at altitudes of 51-53 km and the increase in their intensity above mountain regions Crisp et al, 1990). From these data, and the characteristics of buoyancy waves near the surface (measured from the Venera 9 and Venera 10 landers), the profiles of the total (kinetic + potential) …”

“…The wind velocity fluctuations induced by both tur bulent vortices (transferred by a wind) and buoyancy waves (propagating through the gas) were detected in all of the wind velocity profiles measured from the landers (Burangulov et al, 1974;Counselman et al, 1980;Schubert et al, 1980) of the Vega 1 and Vega 2 balloon missions Sagdeev et al, 1987;Ingersoll, Crisp, and Grossman, 1987;Crisp et al, 1990) kins, 1995). The fluctuations produced by turbulence have a frequency higher than the buoyancy frequency, while the fluctuation frequency produced by waves is lower than the buoyancy frequency.…”

“…The fluctuations produced by turbulence have a frequency higher than the buoyancy frequency, while the fluctuation frequency produced by waves is lower than the buoyancy frequency. The root mean square values of the turbulent fluctuations of velocity σ were accurately determined near the surface from the measurements on the Venera 9 and Venera 10 landers, σ = 0.03 and 0.06 m/s, respectively (Golitsyn, 1978), and at an altitude of about 50 km, σ = 0.4-0.6 m/s, from the data of the long term measurements (about 35 h) conducted by the Vega 1 and Vega 2 bal loons Crisp et al, 1990). For intermediate altitudes, they were approximately esti mated by the velocities measured by several Venera landers (σ ≈ 0.1-0.3 m/s) (Burangulov et al, 1974).…”