Gravity Signatures of Atmospheric Thermal Tides and Waves on Venus

Dynamics in Venus’s massive atmosphere drive large-scale mass redistribution,  generating measurable perturbations in the planet's external gravitational field. Future high-precision gravity measurements from upcoming missions will provide new constraints on the planet’s internal structure and atmospheric mass redistribution. While the deep atmosphere is difficult to observe with traditional remote sensing, these gravitational signatures offer a direct probe into near-surface dynamics. In this study, we analyze atmospheric fields from the Venus Planetary Climate Model (VPCM) to evaluate time-varying gravitational harmonics and assess the expected magnitude of the signal relative to the sensitivity of future gravity measurements. Our analysis shows that low-degree harmonics (l≤4) may reach amplitudes large enough to be distinguishable from the static internal gravity field. Spectral analysis of the simulated harmonics reveals a signal dominated by the diurnal thermal tide, with additional contributions from the semi-diurnal tide and a 35-day wave signal. This suggests that time-variable gravity measurements may be sensitive not only to thermally forced tides, but also to atmospheric wave activity in Venus’s deep atmosphere. We show that the dominant tidal and wave frequencies may be detectable in future gravity-tracking observations. Furthermore, we present a series of sensitivity experiments to determine how variations in atmospheric parameters influence the gravity signal amplitude and temporal structure. By identifying which atmospheric properties control these signatures, we demonstrate how future gravity data can be used to retrieve specific characteristics of the Venusian atmosphere.