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25 pags., 16 figs., 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.

Key Points A dust devil frequency of occurrence of between 1.3 and 3.4 dust devils km−2 sol−1 was derived from MEDA-RDS observations for the first 365 sols, displaying the maximum activity at around noon and increasing as we move from spring into summer We find an average dust devil diameter of 29 m (or a median diameter of 25 m) and maximum and minimum diameters of 132 ± 63.4 m and 5.6 ± 5.5 m Dust devil migration directions are in agreement with the MEDA background wind direction measurements The Mars Environmental Dynamics Analyzer, onboard the Perseverance rover, is a meteorological station that is operating on Mars and includes, among other sensors, the radiometer Radiation and Dust Sensor (RDS). From RDS irradiance observations, a total of 374 dust devils (DDs) were detected for the first 365 sols of the mission (Ls = 6°–182°), which along with wind and pressure measurements, we estimated a DD frequency of formation at Jezero between 1.3 and 3.4 DD km−2 sol−1 (increasing as we move from spring into summer). This frequency is found to be smaller than that estimated at the Spirit or Pathfinder landing sites but much greater than that derived at InSight landing site. The maximum in DD frequency occurs between 12:00 and 13:00 local true solar time, which is when the convective heat flux and lower planetary boundary layer IR heating are both predicted to peak in Jezero crater. DD diameter, minimum height, and trajectory were studied showing (a) an average diameter of 29 m (or a median of 25 m) and a maximum and minimum diameter of 132 ± 63.4 and 5.6 ± 5.5 m; (b) an average minimum DD height of 231 m and a maximum minimum-height of 872 m; and (c) the DD migration direction is in agreement with wind measurements. For all the cases, DDs decreased the UV irradiance, while at visible or near-IR wavelengths both increases and decreases were observed. Contrary to the frequency of formation, these results indicate similar DD characteristics in average for the studied period. 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. 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. Peerreview

Supplementary Tables and Movie associated to the publication: Convective vortices and dust devils detected and characterized by Mars 2020, by Hueso, R. et al. submitted to the Journal of Geophysical Research Planets (2022) This set of data contains the following items: 1. Catalog of pressure drops detected by the Mars 2020 MEDA instrument. This catalog includes pressure drops created by vortices and longer events possibly creatd by passing convective cells. [Table_S1_Mars_Jezero_MEDA__Pressure_Drops.xlsx] 2. Catalog of pressure drops detected by the Mars 2020 MEDA instrument with pressure profiles likely caused by convective vortices. The file contains additional data such as the dusty character of some event and information about the thermal properties of the atmosphere and the terrain. [Table_S2_Mars_Jezero_MEDA_Vortices.xlsx] 3. Physical parameters of selected vortices and dust devils from a selection of the events in Table_S2 after fits with models. [Table_S3_Mars_MEDA_Pressure_Winds_Modeled_Vortices.xlsx] 4. Movie files showing the evolution of pressure in a 10x10 km area from a Large Eddy Simulation with physical characteristics appropiate for Jezero crater on Mars for Ls=42º. [Supplementary_Movie_LES_Mars_Jezero_Ls42.mp4]

Mars rover Perseverance landed on 18 February 2021 on Jezero crater. It carries a weather station that has measured, among other quantities, surface atmospheric pressure. This study covers the first 460 sols or Martian days, a period that comprises a large part of the Martian year, including spring, summer and a part of autumn. Each sol, the pressure has significant changes, and those can be understood as a result of the so-called thermal tides, oscillations of pressure with periods that are fractions of one sol. The mean value of pressure each sols changes with the season, driven by the CO2 sublimation in summer and condensation in winter at both poles. We report oscillations of the mean daily pressure with periods of a few sols, related to waves at distant parts of the planet. Within single sols, we find oscillations of night pressure with periods of tens of minutes, caused by gravity waves. Looking at shorter time intervals, we find the signature of the close passage of vortices such as dust devils, and very rapid daytime turbulent fluctuations. We finally analyze the effects on all these phenomena produced by a regional dust storm that evolved over Jezero in early January 2022. 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. Peerreview

Data Availability Statement All Mars 2020 MEDA data necessary to reproduce each figure shown in this manuscript are available via the Planetary Data System (PDS) Atmospheres node (Rodriguez-Manfredi & de la Torre Juarez, 2021). An exception to this are the LWd values in the 5–80 μm range (Figures 8, 9, and 10 top, Figure 11 top, and Figure 15), and the aerosol opacity values derived from TIRS (Figure 10, middle and Figure 11, top), which are publicly available via the USRA Houston Repository (Martinez et al., 2022). THEMIS retrievals of thermal inertia shown in Figure 7 and TES retrievals of albedo in Figure 14 can be queried and processed using the open-source JMARS (Christensen et al., 2009) and MARSTHERM (Putzig et al., 2013) software. The Mars Environmental Dynamics Analyzer (MEDA) on board Perseverance includes first-of-its-kind sensors measuring the incident and reflected solar flux, the downwelling atmospheric IR flux, and the upwelling IR flux emitted by the surface. We use these measurements for the first 350 sols of the Mars 2020 mission (Ls ∼ 6°–174° in Martian Year 36) to determine the surface radiative budget on Mars and to calculate the broadband albedo (0.3–3 μm) as a function of the illumination and viewing geometry. Together with MEDA measurements of ground temperature, we calculate the thermal inertia for homogeneous terrains without the need for numerical thermal models. We found that (a) the observed downwelling atmospheric IR flux is significantly lower than the model predictions. This is likely caused by the strong diurnal variation in aerosol opacity measured by MEDA, which is not accounted for by numerical models. (b) The albedo presents a marked non-Lambertian behavior, with lowest values near noon and highest values corresponding to low phase angles (i.e., Sun behind the observer). (c) Thermal inertia values ranged between 180 (sand dune) and 605 (bedrock-dominated material) SI units. (d) Averages of albedo and thermal inertia (spatial resolution of ∼3–4 m2) along Perseverance's traverse are in very good agreement with collocated retrievals of thermal inertia from Thermal Emission Imaging System (spatial resolution of 100 m per pixel) and of bolometric albedo in the 0.25–2.9 μm range from (spatial resolution of ∼300 km2). The results presented here are important to validate model predictions and provide ground-truth to orbital measurements. Germán Martínez wants to acknowledge JPL funding from USRA Contract Number 1638782. A. V. R. is supported by the Spanish State Research Agency (AEI) Project MDM-2017-0737, Unidad de Excelencia “María de Maeztu”—Centro de Astrobiología (INTA-CSIC), and by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM). J. J. acknowledges funding from Mastcam-Z ASU subcontract 15-707. R. H., A. S. L., and A. M. were supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22. F. G. acknowledges financial support from the Agencia Estatal de Investigación of the Ministerio de Ciencia e Innovación and the European Regional Development Fund “A way of making Europe” through project the Centre of Excellence “María de Maeztu” award to the Centro de Astrobiología (MDM-2017-0737), and from the Instituto Nacional de Técnica Aeroespacial through Project S.IGS22001. L. M. was supported by CNES and IRIS-OCAV. J. P., M. H., and A.-M. H. are thankful for the Finnish Academy Grant 310509. M.-P. Z. was supported by Grant PID2019-104205GB-C21 funded by MCIN/AEI/10.13039/501100011033. M. de la T. J. acknowledges partial funding from the National Aeronautics and Space Administration (80NM0018D0004). The JPL co-authors acknowledge funding from NASA's Space Technology Mission Directorate and the Science Mission Directorate. Peerreview

We characterize vortex and dust devils (DDs) at Jezero from pressure and winds obtained with the Mars Environmental Dynamics Analyzer (MEDA) instrument on Mars 2020 over 415 Martian days (sols) (Ls = 6°–213°). Vortices are abundant (4.9 per sol with pressure drops >0.5 Pa correcting from gaps in coverage) and they peak at noon. At least one in every five vortices carries dust, and 75% of all vortices with Δp > 2.0 Pa are dusty. Seasonal variability was small but DDs were abundant during a dust storm (Ls = 152°–156°). Vortices are more frequent and intense over terrains with lower thermal inertia favoring high daytime surface-to-air temperature gradients. We fit measurements of winds and pressure during DD encounters to models of vortices. We obtain vortex diameters that range from 5 to 135 m with a mean of 20 m, and from the frequency of close encounters we estimate a DD activity of 2.0–3.0 DDs km−2 sol−1. A comparison of MEDA observations with a Large Eddy Simulation of Jezero at Ls = 45° produces a similar result. Three 100-m size DDs passed within 30 m of the rover from what we estimate that the activity of DDs with diameters >100 m is 0.1 DDs km−2sol−1, implying that dust lifting is dominated by the largest vortices in Jezero. At least one vortex had a central pressure drop of 9.0 Pa and internal winds of 25 ms−1. The MEDA wind sensors were partially damaged during two DD encounters whose characteristics we elaborate in detail. The authors are very grateful to the entire Mars 2020 science operations team. The authors would also like to thank Lori Fenton and an anonymous reviewer for many suggestions that greatly improved the manuscript. This work was supported by Grant PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and by Grupos Gobierno Vasco IT1742-22 and by the Spanish National Research, Development and Innovation Program, through the Grants RTI2018-099825-B-C31, ESP2016-80320-C2-1-R, and ESP2014-54256-C4-3-R. Baptiste Chide is supported by the Director's Postdoctoral Fellowship from the Los Alamos National Laboratory. M. Lemmon is supported by contract 15-712 from Arizona State University and 1607215 from Caltech-JPL. R. Lorenz was supported by JPL contract 1655893. Germán Martínez acknowledges JPL funding from USRA Contract Number 1638782. A. Munguira was supported by Grant PRE2020-092562 funded by MCIN/AEI and by “ESF Investing in your future.” 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), and by the Comunidad de Madrid Project S2018/NMT-4291 (TEC2SPACE-CM). 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). Finnish researchers acknowledge the Academy of Finland Grant 328 310529. Researchers based in France acknowledge support from the CNES for their work on Perseverance.

Perseverance's Mars Environmental Dynamics Analyzer (MEDA) is collecting data at Jezero Crater, characterizing the physical processes in the lowest layer of the atmosphere as no previous instrument did before. Here we show that temperature measurements at four heights capture the response of the atmospheric surface layer to multiple phenomena. We observe the transition from a stable nighttime thermal inversion to a diurnal, highly turbulent convective regime, with large vertical thermal gradients, and where local surface properties (such as Thermal Inertia) play an essential role. Recording multiple daily optical depths yielded higher aerosol concentrations in the morning than in the afternoon. Measured wind patterns are mainly driven by local topography, with a small contribution from regional winds. Daily and seasonal variability of relative humidity shows a complex hydrologic cycle. These observations raise new puzzles in which changes in surface albedo and thermal inertia may play an influential role. On a larger scale, surface pressure shows typical signatures of gravity waves and baroclinic eddies in a part of the seasonal cycle characterized before as low wave activity. These observations, combined and simultaneous, show the rich Jezero’s meteorology, and unveil the diversity of processes driving change on today’s Martian surface.

This article has a correction. Please see: Erratum for the Research Article: “The dynamic atmospheric and aeolian environment of Jezero crater, Mars” - 10 February 2023 Despite the importance of sand and dust to Mars geomorphology, weather, and exploration, the processes that move sand and that raise dust to maintain Mars’ ubiquitous dust haze and to produce dust storms have not been well quantified in situ, with missions lacking either the necessary sensors or a sufficiently active aeolian environment. Perseverance rover’s novel environmental sensors and Jezero crater’s dusty environment remedy this. In Perseverance’s first 216 sols, four convective vortices raised dust locally, while, on average, four passed the rover daily, over 25% of which were significantly dusty (“dust devils”). More rarely, dust lifting by nonvortex wind gusts was produced by daytime convection cells advected over the crater by strong regional daytime upslope winds, which also control aeolian surface features. One such event covered 10 times more area than the largest dust devil, suggesting that dust devils and wind gusts could raise equal amounts of dust under nonstorm conditions. We gratefully acknowledge the huge effort by the entire Mars 2020 team to meet our launch date despite the COVID-19 pandemic, to land and deploy instruments successfully in Jezero crater, and to conduct operations on the surface of Mars since February 2021. This paper arose from discussions within the Mars 2020 Atmospheres Working Group but would not have been possible without the tremendous contributions of everyone involved in Mars 2020 operations. We wish to especially pay tribute to the many team members based in Europe who regularly work through the night as MEDA or SuperCam Payload Uplink and Downlink Leads (PULs/PDLs) or in other roles and to all those who had shifts as Atmospheres Working Group representatives during this period. Last, we gratefully acknowledge the very helpful and constructive comments from both anonymous reviewers. Funding: R.H., A.S.-L., A.M., and T.d.R.-G. are supported by Spanish Ministry of Science and Innovation project PID2019-109467GB-I00 funded by MCIN/AEI/10.13039/501100011033/ and Grupos Gobierno Vasco IT1366-19. I.A., D.T., and V.A. are supported by the Spanish National Research, Development, and Innovation Program through the grants RTI2018-099825-B-C31, ESP2016-80320-C2-1-R, and ESP2014-54256-C4-3-R. L.M., S.N., and J.G.-E. are supported by the Spanish Ministry of Economy and Competitiveness, projects ESP2014-54256-C4-1-R and AYA2015-65041-P; the Spanish Ministry of Science, Innovation, and Universities, projects ESP2016-79612-C3-1-R, ESP2016-80320-C2-1-R, RTI2018-098728-B-C31, and RTI2018-099825-B-C31; and the Spanish Ministry of Science and Innovation’s Centre for the Development of Industrial Technology, projects RTI2018-098728-B-C31 and RTI2018-099825-B-C31. Á.V.-R. and M.-P.Z. are supported by Spanish State Research Agency (AEI) project no. MDM-2017-0737 Unidad de Excelencia “María de Maeztu”–Centro de Astrobiología (INTA-CSIC). M.-P.Z. is supported by the Spanish Ministry of Science and Innovation, PID2019-104205GB-C21. M.M.B. and M.-P.Z. are supported by NASA’s Mars 2020 Participating Scientist Program. All other authors were supported by funding from the Mars 2020 mission, part of the NASA Mars Exploration Program. Work by C.E.N. was additionally funded by the InSight Participating Scientist Program.A portion of this work was performed at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA and funding by SMD, GCD, and STMD. Peerreview

The Mars Regional Atmospheric Modeling System (MRAMS) and a nested simulation of the Mars Weather Research and Forecasting model (MarsWRF) are used to predict the local meteorological conditions at the Mars 2020 Perseverance rover landing site inside Jezero crater (Mars). These predictions are complemented with the COmplutense and MIchigan MArs Radiative Transfer model (COMIMART) and with the local Single Column Model (SCM) to further refine predictions of radiative forcing and the water cycle respectively. The primary objective is to facilitate interpretation of the meteorological measurements to be obtained by the Mars Environmental Dynamics Analyzer (MEDA) aboard the rover, but also to provide predictions of the meteorological phenomena and seasonal changes that might impact operations, from both a risk perspective and from the perspective of being better prepared to make certain measurements. A full diurnal cycle at four different seasons (L 0 , 90 , 180 , and 270 ) is investigated. Air and ground temperatures, pressure, wind speed and direction, surface radiative fluxes and moisture data are modeled. The good agreement between observations and modeling in prior works [Pla-Garcia et al. in Icarus 280:103–113, 2016; Newman et al. in Icarus 291:203–231, 2017; Vicente-Retortillo et al. in Sci. Rep. 8(1):1–8, 2018; Savijärvi et al. in Icarus, 2020] provides confidence in utilizing these models results to predict the meteorological environment at Mars 2020 Perseverance rover landing site inside Jezero crater. The data returned by MEDA will determine the extent to which this confidence was justified., With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737)

We use in situ environmental measurements by the Mars Science Laboratory (MSL) mission to obtain the surface energy budget (SEB) across Curiosity's traverse during the first 2500 sols of the mission. This includes values of the downwelling shortwave solar radiation, the upwelling solar radiation reflected by the surface, the downwelling longwave radiation from the atmosphere, the upwelling longwave radiation emitted by the surface, the sensible heat flux associated with turbulent motions, and the latent heat flux associated with water phase changes. We then analyze their temporal variation on different timescales and relate this to the mechanisms causing these variations. Through its Rover Environmental Monitoring Station, MSL allows for a more accurate determination of the SEB than its predecessors on Mars. Moreover, the unprecedented duration, cadence, and frequency of MSL environmental observations allow for analyses of the SEB from diurnal to interannual timescales. The results presented in this article can be used to evaluate the consistency with predictions from atmospheric numerical models, to validate aerosol radiative properties under a range of dust conditions, to understand the energy available for solar-powered missions, and to enable comparisons with measurements of the SEB by the Perseverance rover at Jezero crater.

C. E. Newman, H. Kahanpaa, M. I. Richardson, G. M. Martinez, A. Vicente‐Retortillo, M. T. Lemmon