Scintillations observed in radio occultation measurements at Venus

Radio occultation measurements at Venus have provided invaluable insights into the planet's atmospheric properties. One particularly intriguing phenomenon observed during these measurements is radio scintillations, characterized by rapid fluctuations in signal intensity. Radio scintillations are caused by small-scale irregularities in the refractive index associated with small-scale variations of the atmospheric density. A possible source of these density variations is vertical propagating internal gravity waves, which originate in the convective layer between about 50 and 55 km altitude.

The frequency dependent radio scintillations were observed at altitude regions of enhanced atmospheric stability, where the propagation of gravity waves is supported. This suggests that gravity waves provide a plausible explanation for the occurrence of radio scintillations. Consequently, the analysis of radio scintillations offers valuable insights into the intensity and global distribution of gravity waves, as well as the strength of the convective winds.

We present the results of a scintillation analysis based on Venus Express X-band radio occultation data and compare them with previous measurements and model calculations. Additionally, we discuss the expected outcomes of the EnVision radio scintillation analysis and highlight the advantages of utilizing both X-band and Ka-band radio signals.