Modulation of Mars’ diurnal polar motion by atmospheric dust cycles

The atmospheric dust cycle plays a crucial role in impacting the atmosphere of Mars, and may also introduce changes in angular momentum that can influence the planet's polar motion. However, the potential connections between polar motion and atmospheric dust cycles have not yet been explored. In this study, we computed atmosphere-excited polar motion and the atmospheric dust cycle index (ADCI) separately from the Mars Climate Database and observed dust optical depth for Martian Years 24–33. We found a strong correlation between diurnal polar motion amplitude change and ADCI, with significance levels above 99%. Our results suggest that atmospheric dust cycles significantly modulate diurnal polar motion. Wavelet transform analyses further revealed other factors, such as water ice clouds, may be responsible for higher frequency modulations of polar motion apart from the dust-related signals. Interdisciplinary studies involving Mars' atmospheric activities and rotational variations can significantly advance our understanding of planetary atmospheric science and global rotational dynamics.