Abstract
AbstractNASA's InSight landed in Elysium Planitia (~4.5°N,136°E) at Ls ~ 296° (November 2018), right after the decay of the 2018 Global Dust Storm (GDS) and before the onset of the 2019 Large Dust Storm (LDS) at Ls ~ 320° (January 2019). InSight's cameras observed a rise in the atmospheric opacities during the storm from ~0.7 to ~1.9, similarly to contemporaneous measurements by Curiosity in Gale crater. Pressure tides were strongly affected at the locations of InSight and Curiosity. In particular, the diurnal pressure mode experienced an abrupt increase during the onset of the LDS, similar to that measured by Curiosity, most likely due to longitudinally asymmetric dust loading. Later, the dust was redistributed around the planet and the semidiurnal mode evolved according to dust opacity in both missions. Before and after the onset of the storm, the observed wind patterns resulted from the interaction between regional and local slope flows induced by topography, which all produced a diurnal perturbation superimposed on a mean flow, dominated by the Hadley cell but with modifications due to channeling effects from the regional topography. However, the onset of the LDS modified this to a scenario consistent with enhanced tidal flows. The local air temperatures are strongly perturbed by the lander's thermal effects, and their retrieval significantly depends on wind patterns, which changed during the course of the dust storm. Observations suggest a decrease in convective vortices during the dust storm; however, vortex activity remained strong during the storm's onset due to the increase in wind speeds.
Highlights
Local and regional dust storms are ubiquitous on Mars, between the southern spring and autumn equinoxes, areocentric solar longitudes Ls ~ 180–360° (e.g., Cantor et al, 2001; Wang & Richardson, 2015; Zurek & Martin, 1993)
NASA's InSight mission landed in Elysium Planitia (~4.5°N, 136°E) at Ls ~ 296°, right after the decay of the MY34 2018 Global Dust Storm (GDS) and before the onset of the MY34 2019 Large Dust Storm (LDS)
The MY34 2019 LDS was observed in detail by several orbiters and on the surface by Mars Science Laboratory (MSL) in Gale crater, which lies a similar distance from the equator and only ~600 km from InSight's landing site
Summary
Local and regional dust storms are ubiquitous on Mars, between the southern spring and autumn equinoxes, areocentric solar longitudes Ls ~ 180–360° (e.g., Cantor et al, 2001; Wang & Richardson, 2015; Zurek & Martin, 1993). The semidiurnal and terdiurnal pressure mode amplitudes were strongly enhanced and peaked after the local opacity maximum measured by MSL's Mast Camera (Mastcam), suggesting deviations in the dust abundance in Gale crater regarding its neighborhood even during the decay of the storm (Viúdez‐Moreiras et al, 2019). This was confirmed by ground‐based observations (Sánchez‐Lavega et al, 2019) and by orbital observations made by the Thermal Emission Imaging System onboard Mars Odyssey (Smith, 2019) and by Mars Climate Sounder (MCS) onboard Mars Reconnaissance Orbiter (MRO) (e.g., Kass et al, 2019; Montabone et al, 2020).
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