Strong nighttime boundary layer activity on Mars caused by thermal perturbations

Abstract The Planetary boundary Layer (PBL) is the region which governs the interactions between the surface and atmosphere. Martian daytime PBL has been shown to have strong turbulent mixing similar to the Earth. Nighttime Martian PBL, yet to be explored further, has been assumed to form under very weak turbulent mixing conditions so far. Here we show that temperature fluctuations caused by large-scale atmospheric variations can induce strong local turbulent mixing and remarkably affect surface-atmosphere exchange processes. Temperature fluctuations as low as 0.5 K can increase the surface momentum flux up to an order of magnitude. Our results reveal the feedback between global/mesoscale atmospheric dynamics and the microscale boundary-layer meteorology, with implication for nighttime dust lifting on Mars due to increased near-surface wind stress.