Abstract DGP2026-5

Scintillations observed in radio occultation measurements at Venus

J. Oschlisniok (1), S. Tellmann (1), M. Pätzold (1), B. Häusler (3), C. Dumoulin (2), P. Rosenblatt (2)

(1) Rheinisches Institut für Umweltforschung, Planetenforschung, Cologne, Germany, (2) Laboratoire de Planétologie et Géosciences, Nantes University, Nantes, France, (3) Institut für Raumfahrttechnik, Universität der Bundeswehr, Munich, Germany

Radio occultation measurements at Venus have provided crucial insights into the planet's atmospheric structure. One particularly striking feature revealed by these observations is the occurrence of radio scintillations—rapid fluctuations in signal intensity. These scintillations are caused by small-scale irregularities in the refractive index, which are linked to fine-scale variations in atmospheric density. A likely source of such density fluctuations is vertically propagating internal gravity waves, originating in the convective layer located between approximately 50 and 55 kilometers in altitude.

Frequency-dependent radio scintillations have been observed in altitude regions characterized by enhanced atmospheric stability, where the propagation of gravity waves is favored. This supports the interpretation that gravity waves are a plausible source of the observed scintillations. As a result, the analysis of radio scintillations provides valuable information about the intensity and global distribution of gravity waves, as well as the strength of convective winds driving their generation.

We present the results of a scintillation analysis based on X-band radio occultation data from Venus Express and compare them with previous observations and model predictions. Furthermore, we discuss the anticipated results of the upcoming EnVision radio scintillation analysis and highlight the advantages of employing both X-band and Ka-band radio signals.