The diverse meteorology of Jezero crater over the first 250 sols of Perseverance on Mars

NASA’s Perseverance rover’s Mars Environmental Dynamics Analyzer is collecting data at Jezero crater, characterizing the physical processes in the lowest layer of the Martian atmosphere. Here we present measurements from the instrument’s first 250 sols of operation, revealing a spatially and temporally variable meteorology at Jezero. We find that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable night-time thermal inversion to a daytime, highly turbulent convective regime, with large vertical thermal gradients. Measurement of multiple daily optical depths suggests aerosol concentrations are higher in the morning than in the afternoon. Measured wind patterns are driven mainly by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations suggest that changes in some local surface properties, such as surface albedo and thermal inertia, play an influential role. On a larger scale, surface pressure measurements show typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle previously characterized as low wave activity. These observations, both combined and simultaneous, unveil the diversity of processes driving change on today’s Martian surface at Jezero crater.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects no. ESP2014-54256-C4- 1-R (also -2-R, -3-R and -4-R); Ministry of Science, Innovation and Universities, projects no. ESP2016-79612-C3-1-R (also -2-R and -3-R); Ministry of Science and Innovation/State Agency of Research (10.13039/501100011033), projects no. ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also -C32 and -C33), RTI2018-099825-B-C31, PID2019-109467GB-I00 and PRE2020-092562; Instituto Nacional de Técnica Aeroespacial; Ministry of Science and Innovation’s Centre for the Development of Industrial Technology; Spanish State Research Agency (AEI) Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”—Centro de Astrobiología; Grupos Gobierno Vasco IT1366- 19; and European Research Council Consolidator Grant no 818602. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development programme within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). G.M. acknowledges JPL funding from USRA Contract Number 1638782. A.G.F. is supported by the European Research Council, Consolidator Grant no. 818602.Peer ReviewedPostprint (published version

Twilight Mesospheric Clouds in Jezero as Observed by MEDA Radiation and Dust Sensor (RDS)

The Mars Environmental Dynamics Analyzer instrument, on board NASA's Mars 2020 Perseverance rover, includes a number of sensors to characterize the Martian atmosphere. One of these sensors is the Radiation and Dust Sensor (RDS) that measures the solar irradiance at different wavelengths and geometries. We analyzed the RDS observations made during twilight for the period between sol 71 and 492 of the mission (Ls 39°–262°, Mars Year 36) to characterize the clouds over the Perseverance rover site. Using the ratio between the irradiance at zenith at 450 and 750 nm, we inferred that the main constituent of the detected high-altitude aerosol layers was ice from Ls = 39°–150° (cloudy period), and dust from Ls 150°–262°. A total of 161 twilights were analyzed in the cloudy period using a radiative transfer code and we found: (a) signatures of clouds/hazes in the signals in 58% of the twilights; (b) most of the clouds had altitudes between 40 and 50 km, suggesting water ice composition, and had particle sizes between 0.6 and 2 µm; (c) the cloud activity at sunrise is slightly higher that at sunset, likely due to the differences in temperature; (d) the time period with more cloud detections and with the greatest cloud opacities is during Ls 120°–150°; and (e) a notable decrease in the cloud activity around aphelion, along with lower cloud altitudes and opacities. This decrease in cloud activity indicates lower concentrations of water vapor or cloud condensation nuclei (dust) around this period in the Martian mesosphere.This work has been funded by the Spanish Ministry of Economy and Competitiveness, through the projects no. ESP2014-54256-C4-1-R (also ESP2014-54256-C4-2-R, ESP2014-54256-C4-3-R, and ESP2014-54256-C4-4-R), Spanish Ministry of Science, Innovation and Universities, projects no. ESP2016-79612-C3-1-R (also ESP2016-79612-C3-2-R and ESP2016-79612-C3-3-R), Spanish Ministry of Science and Innovation/State Agency of Research (10.13039/501100011033), projects no. PID2021-126719OB-C41, ESP2016-80320-C2-1-R, RTI2018-098728-B-C31 (also RTI2018-098728-B-C32 and RTI2018-098728-B-C33), RTI2018-099825-B-C31. RH and ASL were supported by the Spanish project PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/50110001103 and by Grupos Gobierno Vasco IT1742-22. The US co-authors performed their work under sponsorship from NASA’s Mars 2020 project, from the Game Changing Development programme within the Space Technology Mission Directorate and from the Human Exploration and Operations Directorate. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). G.M. acknowledges JPL funding from USRA Contract Number 1638782. ML is supported by contract 15-712 from Arizona State University and 1607215 from Caltech-JPL. A. V-R. is supported by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM)

Winds at the Mars 2020 Landing Site. 2. Wind Variability and Turbulence

Wind speeds measured by the Mars 2020 Perseverance rover in Jezero crater were fitted as a Weibull distribution. InSight wind data acquired in Elysium Planitia were also used to contextualize observations. Jezero winds were found to be much calmer on average than in previous landing sites, despite the intense aeolian activity observed. However, a great influence of turbulence and wave activity was observed in the wind speed variations, thus driving the probability of reaching the highest wind speeds at Jezero, instead of sustained winds driven by local, regional, or large-scale circulation. The power spectral density of wind speed fluctuations follows a power-law, whose slope deviates depending on the time of day from that predicted considering homogeneous and isotropic turbulence. Daytime wave activity is related to convection cells and smaller eddies in the boundary layer, advected over the crater. The signature of convection cells was also found during dust storm conditions, when prevailing winds were consistent with a tidal drive. Nighttime fluctuations were also intense, suggesting strong mechanical turbulence. Convective vortices were usually involved in rapid wind fluctuations and extreme winds, with variations peaking at 9.2 times the background winds. Transient high wind events by vortex-passages, turbulence, and wave activity could be driving aeolian activity at Jezero. We report the detection of a strong dust cloud of 0.75–1.5 km in length passing over the rover. The observed aeolian activity had major implications for instrumentation, with the wind sensor suffering damage throughout the mission, probably due to flying debris advected by winds.The authors acknowledge and thank the Mars 2020 team. The authors would like to thank Editors and two anonymous reviewers for their constructive reviews, which greatly improved this manuscript. This work is supported by the Spanish Ministry of Science and Innovation, under project RTI2018-098728-B-C31. The derived data presented in this work were processed in the DPS24PA system, which is supported by project no. DV2020-ATM-A01. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). The UPV/EHU team is supported by Grant PID2019-109467GB-I00 funded by 1042 MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22

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 Ls ∼ 155°. 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 (ΔP): changes were detected in 3.5%, 43%, and 100% of the dust devils with ΔP 2.5 Pa and ΔP > 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.This research has been funded by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM), by the Spanish State Research Agency (AEI) Project MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (CSIC/INTA), by the Spanish Ministry of Science and Innovation (MCIN)/State Agency of Research (10.13039/501100011033) project RTI2018-098728-B-C31, and by the project PID2021-126719OB-C41, funded by MCIN/AEI/10.13039/501100011033/FEDER, UE. RH, ASL and AM were supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/. Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). We want to thank J. Bell for processing Mastcam-Z projections showing the entire TIRS FOV and to S. Navarro and the entire team for generating the processed wind sensor data

Mars 2020 Perseverance Rover Studies of the Martian Atmosphere Over Jezero From Pressure Measurements

The pressure sensors on Mars rover Perseverance measure the pressure field in the Jezero crater on regular hourly basis starting in sol 15 after landing. The present study extends up to sol 460 encompassing the range of solar longitudes from Ls ∼ 13°–241° (Martian Year (MY) 36). The data show the changing daily pressure cycle, the sol-to-sol seasonal evolution of the mean pressure field driven by the CO2 sublimation and deposition cycle at the poles, the characterization of up to six components of the atmospheric tides and their relationship to dust content in the atmosphere. They also show the presence of wave disturbances with periods 2–5 sols, exploring their baroclinic nature, short period oscillations (mainly at night-time) in the range 8–24 min that we interpret as internal gravity waves, transient pressure drops with duration ∼1–150 s produced by vortices, and rapid turbulent fluctuations. We also analyze the effects on pressure measurements produced by a regional dust storm over Jezero at Ls ∼ 155°.The UPV/EHU team (Spain) is supported by Grant PID2019-109467GB-I00 funded by 1042 MCIN/AEI/10.13039/501100011033/ and by Groups Gobierno Vasco IT1742-22. GM wants to acknowledge JPL funding from USRA Contract Number 1638782. A. Vicente-Retortillo is supported by the Spanish State Research Agency (AEI) Project No. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”- Centro de Astrobiología (INTA-CSIC). Part of the research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). GM wants to acknowledge JPL funding from USRA Contract Number 1638782

Expected atmospheric environment for the Phoenix landing season and location

The Phoenix mission, launched on 4 August 2007, landed in the far northern plains of Mars on 25 May 2008. In order to prepare for the landing events and the 90-sol mission, a significant amount of work has gone into characterizing the atmospheric environment at this location on Mars for northern late spring through midsummer. In this paper we describe the motivation for the work and present our results on atmospheric densities and winds expected during the Phoenix entry, descent, and landing, as well as near-surface pressure, temperature, winds, surface temperature, and visible optical depth expected over the course of the science missio

Observing Mars from Areostationary Orbit: Benefits and Applications

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