The Effect of Bagnold Dunes Slopes on the Short Timescale Air Temperature Fluctuations at Gale Crater on Mars

In situ measurements of how air temperature near the surface responds to changing topography on other planets are rare. The Bagnold dunes were investigated by Mars Science Laboratory's Curiosity rover during its second winter in Gale crater on Mars. The effect of Bagnold dune slopes on the local microclimate air temperature, potential temperature, near‐surface lapse rate, and how they change the variability of short‐lived air temperature fluctuations is described. The oscillations with periods under 24 min are characterized using Fourier analysis. Comparing the sols during the Bagnold dunes exploration to a typical southern winter sol, we characterize the changes in temperature oscillations near the east facing High dune, the west facing Namib dune, as well as in the area between the dunes. Each of the regions had distinct signatures, with the west and east orientation of the dunes affecting the data. Plain Language Summary This manuscript describes the first in situ measurement of the observed effect of terrain slopes on the near‐surface air temperatures of another planet: (a) Air temperatures fluctuated due to convective activity and downslope topographic flows. (b) Both phenomena caused oscillations with different frequencies. (c) The proximity to dunes slopes changed the times of transition from stable to convective atmosphere depending on the orientation of the slopes. The proximity to a steep west face of Namib dune induced rapid oscillations during the evening downslope flow. Key Points Frequency regimes for convective versus topographic air temperature oscillations are found at Gale crater's surface layer Unique air temperature and inversion dynamics on Sols 1222‐1239 were caused by local slopes at the Namib dune Air temperature oscillation frequencies and regime transitions from neutral to convective are modulated by slopes grade and orientation