Activity of Small-Scale Internal Waves in the Northern Polar Atmosphere of Venus by Radio Occultation Measurements of Signal Intensity (Λ = 32 cm) from Venera-15 and -16 Satellites

Abstract

The radio occultation measurements of the signal intensity (λ = 32 cm) of the Venera-15 and -16 satellites, carried out from October 16 to October 31, 1983, are used to analyze the activity of internal waves in the northern polar atmosphere of Venus. Observations of the intensity of radio waves provide important information about the fine-scale structure of the planet’s atmosphere. Comparison of radio occultation measurements and the results of the standard wave theory shows that small-scale fluctuations of the received signal intensity are caused by the spectrum of vertically propagating internal gravity waves. The vertical length of these fluctuations at altitudes of more than 61.5 km is about ~1 km. The model developed for the radiative damping of intensity fluctuations with altitude in the atmosphere of Venus assumes that the intrinsic frequencies of the identified internal waves (measured in a frame of reference moving together with the undisturbed flow) in the sessions under study vary from 3.5 × 10–4 to 9.5 × 10–4 rad/s, and the ratio of horizontal and vertical wavelengths is in the range from 57 to 21.