Vortex‐Dominated Aeolian Activity at InSight's Landing Site, Part 1: Multi‐Instrument Observations, Analysis, and Implications

C Charalambous (1) , J Mcclean (2) , M Baker (3) , W Pike (1) , M Golombek (4) , M Lemmon (5) , V. Ansan (6) , C Perrin (7) , A Spiga (8, 9, 10) , R Lorenz (11) , M Banks (12) , N Murdoch (13) , S Rodriguez (6) , C Weitz (14) , J Grant (15) , N Warner (16) , J Garvin (11) , I Daubar (17) , E Hauber (18) , A Stott (1) , C Johnson (19, 14) , A Mittelholz (20) , T Warren (21) , S Navarro (22) , L Sotomayor (22) , J Maki (4) , A Lucas (23) , D Banfield (24) , C Newman (25) , D Viúdez‐moreiras (22) , J Pla‐garcía (22) , P Lognonné (7) , W Banerdt (4)

1 DEEE - Department of Electrical and Electronic Engineering [London]
2 MIT Haystack Observatory
3 JHU - Johns Hopkins University
4 JPL - Jet Propulsion Laboratory
5 SSI - Space Science Institute [Boulder]
6 LPG - Laboratoire de Planétologie et Géosciences [UMR_C 6112]
7 IPG Paris - Institut de Physique du Globe de Paris
8 LMD - Laboratoire de Météorologie Dynamique (UMR 8539)
9 IPSL (FR_636) - Institut Pierre-Simon-Laplace
10 IUF - Institut universitaire de France
11 APL - Johns Hopkins University Applied Physics Laboratory [Laurel, MD]
12 GSFC - NASA Goddard Space Flight Center
13 ISAE-SUPAERO - Institut Supérieur de l'Aéronautique et de l'Espace
14 PSI - Planetary Science Institute [Tucson]
15 Smithsonian Institution
16 SUNY Geneseo - State University of New York at Geneseo
17 Brown University
18 DLR - German Aerospace Center
19 UBC - University of British Columbia
20 Institute of Geophysics [ETH Zürich]
21 University of Oxford
22 CAB - Centro de Astrobiologia [Madrid]
23 IPGP (UMR_7154) - Institut de Physique du Globe de Paris
24 Cornell University [New York]
25 Aeolis Research

We report the aeolian changes observed in situ by NASA's InSight lander during the first 400 sols of operations: Granule creep, saltation, dust removal, and the formation of dark surface tracks. Aeolian changes are infrequent and sporadic. However, on sols, when they do occur, they consistently appear between noon to 3 p.m., and are associated with the passage of convective vortices during periods of high vortex activity. Aeolian changes are more frequent at elevated locations, such as the top surfaces of rocks and lander footpads. InSight observed these changes using, for the first time, simultaneous in-situ and orbital imaging and high-frequency meteorological, seismological, and magnetic measurements. Seismometer measurements of ground acceleration constrain the timing and trajectory of convective vortex encounters, linking surface changes to source vortices. Magnetometer measurements show perturbations in magnetic field strength during the passage of convective vortices consistent with charged-particle motion. Detachment of sand-scale particles occurs when high background winds and vortex-induced turbulence provide a peak surface friction wind speed above the classic saltation fluid threshold. However, detachment of dust- and granule-scale particles also occurred when the surface friction wind speed remained below this threshold. This may be explained by local enhancement of the surface roughness and other effects described here and further studied in Part 2 (Baker et al., 2021). The lack of saltation and bright dust-coated surfaces at the InSight landing site implies surface stability and the onset of particle motion may be suppressed by dust “cushioning.” This differentiates the InSight landing site from other areas on Mars that exhibit more aeolian activity.

Domaines: Planétologie et astrophysique de la terre [astro-ph.EP]

C Charalambous, J Mcclean, M Baker, W Pike, M Golombek, et al.. Vortex‐Dominated Aeolian Activity at InSight's Landing Site, Part 1: Multi‐Instrument Observations, Analysis, and Implications. Journal of Geophysical Research. Planets, 2021, 126 (6), ⟨10.1029/2020je006757⟩. ⟨hal-03657987⟩