Dust Lifting Through Surface Albedo Changes at Jezero Crater, Mars

We identify temporal variations in surface albedo at Jezero crater using first-of-their-kind high-cadence in-situ measurements of reflected shortwave radiation during the first 350 sols of the Mars 2020 mission. Simultaneous Mars Environmental Dynamics Analyzer (MEDA) measurements of pressure, radiative fluxes, winds, and sky brightness indicate that these albedo changes are caused by dust devils under typical conditions and by a dust storm at L-s similar to 155 degrees. The 17% decrease in albedo caused by the dust storm is one order of magnitude larger than the most apparent changes caused during quiescent periods by dust devils. Spectral reflectance measurements from Mastcam-Z images before and after the storm indicate that the decrease in albedo is mainly caused by dust removal. The occurrence of albedo changes is affected by the intensity and proximity of the convective vortex, and the availability and mobility of small particles at the surface. The probability of observing an albedo change increases with the magnitude of the pressure drop (Delta P): changes were detected in 3.5%, 43%, and 100% of the dust devils with Delta P < 2.5 Pa, Delta P > 2.5 Pa and Delta P > 4.5 Pa, respectively. Albedo changes were associated with peak wind speeds above 15 m.s(-1). We discuss dust removal estimates, the observed surface temperature changes coincident with albedo changes, and implications for solar-powered missions. These results show synergies between multiple instruments (MEDA, Mastcam-Z, Navcam, and the Supercam microphone) that improve our understanding of aeolian processes on Mars.

Automated summary

We analyzed the temporal variations in surface albedo at Jezero crater during the first 350 sols of the Mars 2020 mission. The measurements showed that the albedo changes were caused by dust devils under normal conditions and a dust storm at a specific solar longitude. The albedo decrease during the dust storm was significantly larger than the changes caused by dust devils during calm periods.