Effects of the MY34/2018 Global Dust Storm as Measured by MSL REMS in Gale Crater

Abstract

The Rover Environmental Monitoring Station (REMS) instrument is on board NASA's Mars Science Laboratory (MSL) Curiosity rover. REMS has been measuring surface pressure, air, and ground brightness temperature, relative humidity, and ultraviolet (UV) irradiance since MSL's landing in 2012. In Mars Year (MY) 34 (2018) a global dust storm reached Gale Crater at Ls ~ 190°. REMS offers a unique opportunity to better understand the impact of a global dust storm on local environmental conditions, which complements previous observations by the Viking landers and Mars Exploration Rovers. All atmospheric variables measured by REMS are strongly affected albeit at different times. During the onset phase, the daily maximum UV radiation decreased by 90% between sols 2075 (opacity ~1) and 2085 (opacity ~8.5). The diurnal range in ground and air temperatures decreased by 35 and 56 K, respectively, with also a diurnal‐average decrease of ~2 and 4 K respectively. The maximum relative humidity, which occurs right before sunrise, decreased to below 5%, compared with prestorm values of up to 29%, due to the warmer air temperatures at night, while the inferred water vapor abundance suggests an increase during the storm. Between sols 2085 and 2130, the typical nighttime stable inversion layer was absent near the surface as ground temperatures remained warmer than near‐surface air temperatures. Finally, the frequency domain behavior of the diurnal pressure cycle shows a strong increase in the strength of the semidiurnal and terdiurnal modes peaking after the local opacity maximum, also suggesting differences in the dust abundance inside and outside Gale.

Martian Year 34 Column Dust Climatology from Mars Climate Sounder Observations: Reconstructed Maps and Model Simulations

“…Hence, at the Curiosity site, both the amplification of the diurnal and semidiurnal modes in the simulated surface pressure are predicted to occur before dust opacity increases locally. This is in agreement with the observations by Curiosity of the diurnal pressure amplitude, which is found to react about 4 sols before the increase of dust opacity observed by Curiosity in Gale Crater (Viúdez-Moreiras et al, 2019).…”

Effects of a Large Dust Storm in the Near‐Surface Atmosphere as Measured by InSight in Elysium Planitia, Mars. Comparison With Contemporaneous Measurements by Mars Science Laboratory

“…inViúdez-Moreiras et al, 2019).The semidiurnal pressure mode amplitude increased and decreased with τ during the LDS at both InSight and MSL(Figure 8), as expected from the theory described above and in accordance with previous analysis showing a good correlation between the semidiurnal pressure mode amplitude and dust opacity(Guzewich et al, 2016;Hess et al, 1977;Leovy & Zurek, 1979;Lewis & Barker, 2005;Wilson & Hamilton, 1996;Zurek & …”

“…The near-surface water vapor abundance, inferred from the relative humidity, pressure, and temperature measurements, suggested an overnight increase during the storm at MSL's general location in Gale crater and a decrease during the daytime, although with a high level of uncertainty due to MSL's sensor constraints (Viúdez-Moreiras et al, 2019). It was hypothesized in Viúdez-Moreiras et al (2019) that the combined effect of a reduction in the strength of an adsorption and desorption mechanism in the regolith, which is likely driving the diurnal cycle in the near-surface water vapor abundance, and the enhanced vertical mixing suggested at night during the dust storm period could be driving the observed effect in the diurnal cycle considering that the inferred water vapor abundances during the GDS are correct. Savijärvi et al (2020) attempted to simulate the MY34 GDS surface water abundance within Gale crater by means of a one-dimensional model and further assumptions, but simulations did not match the observations, and they proposed an additional source of water vapor to minimize the model mismatch.…”

“…During storm onset, the diurnal maximum in the UV radiation decreased by 90% between Sols 2075 (MSL's Mast Camera optical depth ~1) and 2085 (optical depth ~8.5). The diurnal amplitude in air and ground temperatures were reduced by 56 and 35 K, respectively, along with a decrease in the daily mean of ~2 and ~4 K. Between MSL Sols 2085 and 2130, the usual stable inversion layer during nighttime was absent near the surface, as the ground presented higher temperatures than near‐surface air masses (Viúdez‐Moreiras et al, 2019). The daytime surface‐to‐air thermal gradient and, probably, wind speeds were strongly reduced, resulting in no rapid, short‐lived pressure drops (associated with convective vortices) exceeding 0.5 Pa or dust devils being observed by MSL, between Sols 2083 and 2107 (Guzewich et al, 2019).…”

Visibility and Line‐of‐Sight Extinction Estimates in Gale Crater During the 2018/MY34 Global Dust Storm

“…GDSs loft dust >60 km into the atmosphere (e.g., Clancy et al, , and references therein) and take several months to dissipate. GDSs have significant effects on atmospheric features such as diurnal pressure variations, circulation, and atmospheric heating (e.g., Guzewich et al, ; Videz‐Moreiras et al, ). However, the series of events that lead to the formation of a GDS are not well known.…”