Dust Lifting Observations With the Mars Science Laboratory Navigation Cameras.

Martian dust lifting is believed to occur through two primary mechanisms: dust devils and wind stress forced dust lifting. Gale Crater's varied terrain and meteorology provide a unique in situ perspective on Martian dust lifting, with the Mars Science Laboratory Curiosity rover passing through both conditions and locations detrimental to dust lifting (e.g., the crater floor) and those with active sand motion and frequent dust lifting (e.g., the Bagnold Dunes). Between Ls = 248° in Mars Year 33 and Ls = 51° in Mars Year 37, over ∼3.5 Mars years and 2,300 sols, the rover's Navigation Cameras took 1,260 dedicated image sequences to search for dust lifting. Approximately 42.7% of all sequences, and 9.5% of the total images have shown active dust lifting, both dust devils and linear/straight‐line wind stress dust lifting. 79% of dust lifting events are classified as dust devils, while ∼16% are linear wind stress dust lifting and the remainder are of an indeterminate type. We analyze this large catalog of dust lifting events to provide ground truth on theoretical and model expectations of dust lifting and show that dust lifting in Gale Crater occurs throughout the Martian year, is strongly peaked in frequency near solar noon (even after accounting for observational biases), and that dust lifting shows an affinity for sand‐covered surfaces which highlights the importance of saltating sand grains for Martian dust lifting in both dust devils and wind stress forced lifting. Plain Language Summary: Airborne dust is an important control on the modern Martian climate. Dust is lifted into the air by two primary mechanisms: dust devils (rotating columns of air that are also common in dry areas on Earth) and the force of straight‐line winds acting on dust‐covered surfaces. The Mars Science Laboratory Curiosity rover Navigation Cameras have taken regular movies to search for dust lifting in the Gale Crater. Approximately 42.7% of all sequences, and 9.5% of the total images have shown active dust lifting and we analyze this large catalog of events to better understand the mechanisms and conditions that lift dust into the air on Mars. We find that dust lifting in Gale Crater is more strongly clustered near solar noon than previously expected from analyses of air pressure and that dust lifting often occurs on sand‐covered terrains, suggesting that the motion of sand grains across the surface supports dust lifting. Key Points: The Mars Science Laboratory Navigation Cameras have taken 1,260 dedicated image sequences searching for dust liftingApproximately 42.7% of all sequences and 9.5% of all images show active dust liftingDust lifting in the Gale Crater most frequently occurs on sand‐covered surfaces [ABSTRACT FROM AUTHOR]