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

Abstract

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.

Gravity Wave Observations by the Mars Science Laboratory REMS Pressure Sensor and Comparison With Mesoscale Atmospheric Modeling With MarsWRF

“…The greatly reduced diurnal variability in air and ground temperature during the storm (Guzewich et al, 2019;Viúdez-Moreiras et al, 2019) also appeared to stabilize the perturbations to temperature seen in nearly all other sols of the mission. Throughout the mission, the daytime temperature behavior is consistent with turbulent convection (Miller et al, 2018) and is the expected response to radiative forcing from modeling and known from previous landed missions .…”

“…Recently, Miller et al. (2018) and Banfield et al. (2020) identified a previously unknown atmospheric “quiet” period immediately after sunset and extending for 2–4 h in pressure and temperature data from both MSL and the InSight lander (also seen in wind measurements by InSight).…”

“…These extended blocks consist of (a) 1‐h observations every 6 h, shifting an hour earlier each sol, hence covering a full diurnal cycle every 6 sols, and (b) 3‐h observations that cover the same 3 h for 3 sols before shifting 3 h earlier, hence cover a full diurnal cycle in 3‐h blocks every 24 sols. The hour surrounding local solar noon is also observed on nearly every sol, due to the expected peak of UV radiation and coinciding with the maximum convective vortex activity at that time‐of‐day (e.g., Miller et al., 2018; Newman et al., 2019). Newman et al.…”

Thermal Forcing of the Nocturnal Near Surface Environment by Martian Water Ice Clouds

“…Another potential source of the twilight warmings are orographic winds, which would be expected to repeat their pattern daily, but we do not observe this AT perturbation every sol (Figures 2c and 2d), nor is the same pattern of temporary heating observed over sequential sols. Additionally, downslope winds capable of causing sudden short‐lived increases in AT do so via oscillations during the evening transitions (e.g., Lehner et al., 2015 and references therein), but the signal within Figures 2a and 2b does not always show oscillations, and occurs at a time where on Earth (Lehner et al., 2015) and on Mars (Miller et al., 2018) near surface temperatures typically show stable behavior.…”

Gravity Wave Observations by the Mars Science Laboratory REMS Pressure Sensor and Comparison with Mesoscale Atmospheric Modeling with MarsWRF

“…These extended blocks consist of (a) 1-h observations every 6 h, shifting an hour earlier each sol, hence covering a full diurnal cycle every 6 sols, and (b) 3-h observations that cover the same 3 h for 3 sols before shifting 3 h earlier, hence cover a full diurnal cycle in 3-h blocks every 24 sols. The hour surrounding local solar noon is also observed on nearly every sol, due to the expected peak of UV radiation and coinciding with the maximum convective vortex activity at that time-of-day (e.g., Miller et al, 2018;Newman et al, 2019). Newman et al (2017) and Guzewich et al (2019) show examples of the REMS observation cadence.…”