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Clouds on Mars are primary elements for understanding the past and present climate of the planet. Cloud particles can affect the energy balance of the planet, and so the atmospheric dynamic, as well as influence the vertical distribution of dust particles through dust scavenging. The dust scavenging by clouds has critical consequences in the water cycle of the planet; e.g. regions in the atmosphere with insufficient quantity of dust particles (or condensation nuclei) can inhibit the formation of H2O clouds and thus lead to the presence of water vapor in excess of saturation. The study of these interactions requires observations whose analysis allows us to infer simultaneously the properties of both the clouds and dust. To address these observations, the Radiation and Dust Sensor (RDS) is part of the Mars Environmental Dynamics Analyzer (MEDA) payload onboard of the Mars 2020 rover Perseverance.In this work we analysed the RDS observations made during twilight in the period Ls 39◦-262◦ to characterize the clouds above ∼ 30 km over the Perseverance rover site. From the ratio between the irradiance measured at zenith at 450 nm and 750 nm, we inferred that from Ls= 39◦ to 150◦ (referred as the cloudy period), water ice is the main constituent of the detected high-altitude aerosol layers. For Ls 150◦-262◦ dust is the main aerosol present. A total of 161 twilights were analysed in the cloudy period with a radiative transfer code in spherical geometry. Among other results we found: i) signatures of clouds or hazes on the RDS signals in the 58 % of the twilights; ii) most of the clouds were at altitudes between 40 km and 50 km and with particle sizes between 0.6 μm and 2 μm (in effective radius); iii) the cloud activity at sunrise is slightly higher that at sunset (65 % against 52 %), likely due to the differences in temperature; iv) the cloudiest time in Perseverance site and with the greatest cloud opacities is in Ls 120◦-150◦; and v) a notable decrease in the cloud activity around the aphelion (Ls ∼ 70◦), along with lower cloud altitudes and opacities. The drop in cloud activity around Ls ∼ 70◦ indicates lower concentrations of water vapor or cloud nuclei (dust) around this period in the Martian mesosphere. In this presentation, we will discuss the implications of our results on the water cycle of the planet.

Pressure measurements by the MEDA sensor on board Perseverance Rover show oscillations in a wide range of temporal scales, from the seasonal evolution of average pressure to rapid fluctuations on the scale of a few seconds. In this work, we profit from an entire Martian Year of pressure measurements to analyse the seasonal and daily evolution of rapid fluctuations, a signature of atmospheric turbulence. We find that during the full Martian year, fluctuations are enhanced at convective hours of the day, but the intensity of fluctuations is modulated through the seasons. At nighttime, the first half of the Martian years is characterized by an almost complete absence of fluctuations with an especially calm period in the early morning, while bursts of fluctuation become common in the dusty season. We also analyse the change of the daily pattern induced by regional dust storms at Jezero. We study the power spectra of the fluctuations to try to infer information about different turbulent regimes at the surface layer and their dependence on local time and season. Finally, we explore possible correlations with the dust load of the atmosphere and the temperature gradients, and we look at the origin of nighttime bursts of turbulence.

The Thermal Infrared Sensor (TIRS; Sebastián et al., 2021; Martínez et al., 2023) is one of the six sensor packages of the Mars Environmental Dynamics Analyzer (MEDA; Rodríguez-Manfredi et al., 2021), which in turn is one of the seven science instruments on board Perseverance. Here we show a summary of TIRS scientific highlights during the first Martian year of operations. In particular, TIRS is providing the first in situ determination of the surface radiative budget, direct determination of broadband albedo and thermal inertia (Martínez et al., 2023; Savijärvi et al., 2022), and around-the-clock determination of aerosol opacities (Smith et al., 2023). In addition, TIRS is providing ground-truth to orbital retrievals of thermal inertia and albedo, as well as geophysical characterization of the uppermost surface of the regolith during Phobos and Deimos eclipses. In synergy with other instruments, TIRS is being used to determine vertical profiles of temperature (Munguira et al., 2023), to detect dust lifting from sudden changes in albedo (Vicente-Retortillo et al., 2023), and to assess changes in the water content of the Martian soil (Hausrath et al., 2023), including the potential formation of frost. TIRS observations are critical to achieve MEDA’s first programmatic objective (validate global atmospheric models by measuring the radiative surface budget in preparation for future human exploration). Also, TIRS observations are important in support of flights of Ingenuity and therefore for the design and operations of future drones. References: Hausrath, E. M. et al. (2023), The SuperCam team and the Regolith working group, An Examination of Soil Crusts on the Floor of Jezero crater, Mars, Journal of Geophysical Research: Planets (accepted). Martínez, G. M. et al. (2023), Surface Energy Budget, Albedo and Thermal Inertia at Jezero Crater, Mars, as Observed from the Mars 2020 MEDA Instrument, Journal of Geophysical Research: Planets (accepted). Munguira, A. et al. (2023), Near Surface Atmospheric Temperatures at Jezero from Mars 2020 MEDA measurements, Journal of Geophysical Research: Planets (under review). Rodriguez-Manfredi, J.A. et al. (2021), The Mars Environmental Dynamics Analyzer, MEDA. A suite of environmental sensors for the Mars 2020 mission, Spa. Sci. Rev., 217(3), 1-86. Savijärvi, H. I. et al. (2022), Surface energy fluxes and temperatures at Jezero crater, Mars, Journal of Geophysical Research: Planets: e2022JE007438. Sebastián, E. et al. (2021), Thermal calibration of the MEDA-TIRS radiometer onboard NASA's Perseverance rover, Acta Astronautica, 182,144-159. Smith, M. D. et al. (2023), Diurnal and Seasonal Variations of Aerosol Optical Depth Observed by MEDA/TIRS at Jezero Crater, Mars, Journal of Geophysical Research: Planets (accepted). Vicente-Retortillo, A. et al. (2023), Dust Lifting Through Changes in Albedo at Jezero Crater, Mars, Journal of Geophysical Research: Planets (under review).

We use data from the MEDA instrument on Mars 2020 to study the evolution of atmospheric and surface temperatures at Jezero. The measurements correspond to four height levels from the surface to ~40 m and together they allow us to examine multiple aspects of the near-surface meteorology at Jezero. We extend the analysis of near-surface temperatures of Munguira et al. (JGR:Planets 2023), which covered the period from Ls 13º to Ls 203º, over a full Martian year. We show the seasonal evolution of temperatures, including temperature fluctuations and thermal gradients, which are affected by the properties of the terrain traversed by Perseverance. We will focus on a physical description of the thermal processes that take place in the Convective Boundary Layer at Jezero. We compare near-surface temperatures with the atmospheric opacity around-the-clock retrieved by Smith et al. (2022) and with daily averages of optical depth measured by MastCam-Z (Bell et al. 2022). After Ls 203º, atmospheric waves coming across Jezero predicted by atmospheric models are expected to contribute to shaping temperatures producing thermal oscillations on time-scales of a few sols. This effect is accompanied by an enhanced variability of atmospheric opacity and both effects contribute to produce a higher variability on temperatures. References:[1] Munguira, A. et al. (2023). Near Surface Atmospheric Temperatures at Jezero from Mars 2020 MEDA Measurements. JGR: Planets.[2] Smith, M.D. et al. (2022). Diurnal and Seasonal Variations of Aerosol Optical Depth Observed by MEDA/TIRS at Jezero Crater, Mars. In Seventh international workshop on the Mars atmosphere: Modelling and observations (pp. 14-17).[3] Bell, J.F. et al. (2022). Geological, multispectral, and meteorological imaging results from the mars 2020 perseverance rover in jezero crater. Science Advances, 8 (47), eabo4856. doi: 10.1126/sciadv.abo485

The Mars Environmental Dynamics Analyzer (MEDA) instrument, on board the NASA’s Mars 2020 Perseverance rover, includes a number of sensors to characterize the Martian atmosphere. One of this 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◦) 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◦ to 150◦ (cloudy period), an dust from Ls 150◦-262◦. A total of 161 twilights were analyzed in the cloudy period using a radiative transfer code and we found: i) signatures of clouds/hazes in the signals in the 58 % of the twilights; ii) most of the clouds had altitudes between 40-50 km, suggesting water ice composition, and had particle sizes between 0.6 and 2 μm; iii) the cloud activity at sunrise is slightly higher that at sunset, likely due to the differences in temperature; iv) the time period with more cloud detections and with the greatest cloud opacities is during Ls 120◦-150◦; and v) a notable decrease in the cloud activity around the 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.

Since February 18, 2021, Perseverance has been exploring Jezero Crater (18ºN, 77ºE). The meteorology of this location is being investigated with the Mars Environmental Dynamics Analyzer (MEDA) [1], which among many other sensors has 5 Air Temperature Sensors (ATS) to measure near surface temperatures. These sensors are located at two altitudes: two are at 0.85 m, in the front of the rover, and three are at 1.45 m around the Remote Sensing Mast (RSM), distributed azimuthally so that at least one sensor is located upwind. Local air temperatures are measured with a frequency that can be as high as 2 Hz. In addition, the temperature of the surface and at an approximate altitude of about 40 m are measured with the Thermal Infrared Sensor (TIRS), which operates with a sampling frequency of 1 Hz. MEDA records atmospheric variables typically over 50% of a full sol. Here we present consolidated analysis of data up to sol 400, which covers a period from the start of northern Spring (Ls=5º) to early Autumn (beyond Ls=180º). This analysis takes into account different instrumental effects affecting ATS and TIRS which have been characterized over the course of the mission. Firstly, we will present the daily temperature cycle at Jezero, including mean values and its fluctuations plus their daily and seasonal evolution. Hence, we report phenomena at various altitudes, in different time scales, ranging from thermal tides to continuous rapid fluctuations, as well as the effects caused by the different environments as Perseverance explores Jezero. The convective and calmed regimes, at daytime and nighttime respectively, and the transitions between them are well differentiated in the MEDA data and can be well characterized. We will also discuss vertical thermal gradients (surface to 40 m altitude) along the mission and the evolution of nighttime inversions. Secondly, we quantify the influence of different forcings on temperatures: The thermal changes associated with clouds, dust load, variations of the solar flux and changes in the surface properties on the ground and near-surface temperatures. Specific effects associated with a regional dust storm over Jezero will be presented. Lastly, we will comment on the comparison of temperatures at Jezero with in situ data from other locations [2-3] and models [4-5]. [1] Rodriguez-Manfredi, J. A., et al. (2021). The Mars Environmental Dynamics Analyzer, MEDA. A suite of environmental sensors for the Mars 2020 mission. Space science reviews, 217(3), 1-86. [2] Davy, R., et al. (2010). Initial analysis of air temperature and related data from the Phoenix MET station and their use in estimating turbulent heat fluxes. Journal of Geophysical Research: Planets, 115(E3). [3] Mason, E. L., & Smith, M. D. (2021). Temperature fluctuations and boundary layer turbulence as seen by Mars Exploration Rovers Miniature Thermal Emission Spectrometer. Icarus, 360, 114350. [4] Newman et al. (2020). Multi-model Meteorological and Aeolian Predictions for Mars2020 and the Jezero Crater Region, Space Sci. Rev. 215, 148. [5] Pla-García et al., (2020). Meteorological Predictions for Mars 2020 Perseverance Rover Landing Site at Jezero, Space Sci. Rev., 215, 148.

The aim of this investigation is to carry out a study of the variability of nocturnal atmospheric turbulence at Jezero crater supported by modeling effort and monitored by MEDA. The rapid turbulent kinetic energy (hereafter TKE), wind and pressure fluctuations observed during nighttime both with modeling and MEDA is a clear indicator of nocturnal turbulence. The origin of this nocturnal turbulence is explored with MRAMS and, as opposed to Gale crater, low evidence of significant gravity waves activity during the whole period studied was found. On the contrary, the nighttime turbulence at Jezero crater could be shear driven and may be explained due to an enhanced mechanical turbulence produced by increasingly strong shear (onset of a strong low-level jet) at the nocturnal inversion interface. As the nocturnal inversion develops, the winds above become decoupled from the surface and the decrease in friction produces a net acceleration [refs 4, 5, 6, 7]. Once the critical Richardson Number is reached (Ri ∼< 0.25, Figure 3), shear instabilities can mix warmer air aloft down to the surface [refs 8, 9, 10]. 1. Introduction The Mars 2020 Perseverance rover landed in Mars in February 2021 at 18.44°N 77.45°E within and near the northwest rim of Jezero crater. The MEDA weather station is aboard Perseverance rover [ref 1]. 2. MRAMS mesoscale simulations MRAMS was applied to Mars 2020 landing site region using nested grids with a spacing of 330 meters on the innermost grid that is centered over the landing site [ref 2]. 3. Nighttime turbulence modeled with MRAMS The effect of subgrid-scale eddies is captured within MRAMS via a prognostic TKE (Figure 1) equation [ref 3]. MRAMS shows a peak in TKE during the afternoon, which is consistent with the modeled high-frequency variations in air temperatures [Figure 3 of ref 2]. The sudden increase in air temperature during the evenings [Figure 3 of ref 2] at the onset of radiative cooling is produced by mechanically driven turbulence since the atmosphere is stable and non-convective in the evening. The model does often show small increases of TKE during the night (Figure 1), especially during Ls=180º (corresponding to Mars 2020 sol 362) and some during Ls 105 and Ls 160 (corresponding to Mars 2020 sols 216 and 326), that could be associated with the turbulent aspects of the nighttime dynamical flows when compared with nearby locations with more flat topography. During the late evening and night, MRAMS is resolving thermal variations [2, Figure 3] and does often show small increases of TKE at that time (Figure 1). The rapid air temperature fluctuations modeled at night in all seasons is indicative of nocturnal turbulence. There is low evidence of significant wave activity during the whole period studied and only some gravity waves were found. The nighttime turbulence could be attributed to shear driven turbulence and may be explained due to an enhanced mechanical turbulence driven by increasingly strong shear, with the onset of the nocturnal low-level jet, at the nocturnal inversion interface (an example on Figure 2). Based on GCM model efforts, looks like the low-level jet is a large scale circulation feature. The westward wind at 2 km altitude shown on Figure 2 is also show up nicely in the MCD. The jet could be forced by the diurnal cycle. The dustier atmosphere, when arrival of northern autumn equinox, also contributes to decrease the nighttime Richardson number by two means: strengthening of the nighttime low-level jet deeping the near-surface wind shear and weakening near-surface atmospheric stability by increasing the nighttime surface temperature and decreasing of atmospheric temperature. A third possible strengthening of the nighttime turbulence at Jezero could be the convergence, after 01:00 LTST, of downslope winds blowing from NW rim fighting against SE winds blowing both from east crater rims and from Jezero mons (located SE outside the crater), producing a big whirlpool inside the crater (Figure 4) that could be the responsible of the high variability of wind directions observed by MEDA. 4. Nightime turbulence observed with MEDA The rapid fluctuations of pressure (moreover during high dust periods), TKE (derived only with horizontal wind speeds, that will be updated with vertical winds in the future) and wind speeds observed during nighttime with MEDA (Figures 5 and 6) is a clear indication of nocturnal turbulence. 5. Figures Figure 1: TKE diurnal cycle predicted with MRAMS for Jezero crater at Ls0, 60, 90, 105, 160, 180 and 270. Figure 2: MRAMS vertical cross-section (Jezero’s west rim to east rim) at 21:35 LTST of Ls=180º -corresponding to Mars 2020 sol #362- of total wind (zonal + meridional) in colored shadowed, zonal + vertical (exaggerated x5) wind in white arrows and TKE in black contours. The west crater rim is the hill on the left. Perseverance rover is located at x ≈ 17 km. Figure 3: MRAMS vertical profiles of wind magnitude, wind shear, Richardson number (Ri) and TKE for Ls180 at Mars 2020 location corresponding to Mars 2020 sol #362 (Ls=180º). Once the critical Richardson Number is reached (Ri ∼< 0.25, red line). Figure 4: Near-surface winds (vectors) and potential temperature (shaded) as predicted on numerical grid 5. Vectors are plotted at every other grid point. Topography contours are shown in black. Wind vector scale is shown in the bottom right area of the panels. hh:mm LTST on the top right. A big whirlpool inside the crater could be responsible for the large variability of wind directions observed by MEDA after 01:00 LTST. Figure 5: MEDA TKE (derived only with horizontal wind speeds, that will be updated with vertical winds in the future), wind direction and horizontal wind speed instantaneous measurements for the period 00:14 to 00:23 LTST at sol #73. Figure 6: Diurnal cycle of MEDA TKE averaged over 5 min for sols #73-87. 6. References [1] Rodriguez-Manfredi et al. 2020; [2] Pla-Garcia et al. 2021; [3] Mellor and Yamada 1974; [4] Davis 2000; [5] Blackadar 1957; [6] Thorpe and Guymer 1977; [7] Mahrt 1981; [8] Miles 1961; [9] Banfield et al. 2020; [10] Chatain et al. 2021

The Mars 2020 Perseverance rover is developing its mission in Jezero crater [1], a north tropical location that is rich in vortices and dust devils [2]. The MEDA instrument [3] collects atmospheric data at a typical frequency of 1 Hz with several sensors including pressure and winds. It also registers data about atmospheric dust with its set of photodiodes [4]. Together, these data are providing a large set of detections of vortices and dust devils [2, 5] that can be used to investigate the physical properties of the vortices and their effects on the environment though the combination of additional data obtained by MEDA. Here we present a physical characterization of dust devils detected with the pressure data and confirmed as dust devils from the set of photodiodes on MEDA. We show that the combination of pressure, winds and a simple model of drifting vortices [6] can fit the observations of many of these events determining their true central pressure drop, diameter and maximum circulation winds. The quality of the comparisons depend on the varying quality of the wind measurements and is better in short encounters with small vortices than in long encounters with large dust devils. We examine how the vortices characteristics, i.e. their true diameter, minimum distance of the encounter, central pressure drop and maximum wind intensity compare with the detection of dust and its basic inferred abundance and explore the consequences for the efficiency of vortices of different sizes and intensities to raise dust from the Martian surface. We also compare these vortex parameters with environment thermal properties, such as the thermal gradient from the surface and the air, and the thermal perturbations caused by the vortex in a selection of the best observed cases. A comparison with main properties of vortices observed in the different surveys of dust devil activity carried on by the cameras onboard Perseverance will be also presented. References:[1] Farley, K.A. et al. Mars2020 Mission Overview, Space Sci. Rev., 216, 142 (2020). Doi: 10.1007/s11214-020-00762-y[2] Newman, C.E. et al. The dynamic atmospheric and aeolian environment of Jezero crater, Mars, Science Advances (in press).[3] Rodriguez-Manfredi, J.A. et al. The Mars Environmental Dynamics Analyzer, MEDA. A Suite of Environmental Sensors for the Mars 2020 Mission, Space Science Reviews, 217, 48 (2021), doi:10.1007/s11214-021-00816-9.[4] Apestigue, V. et al. Radiation and Dust Sensor for Mars Environmental Dynamic Analyzer Onboard M2020 Rover. Sensors, 22, 2907 (2022). doi:10.3390/s22082907[5] Jackson, B. Vortices and Dust Devils as Observed by the Mars Environmental Dynamics Analyzer Instruments on Board the Mars 2020 Perseverance Rover, The Planetary Science Journal, 3, 20 (2022). Doi: 103847/PSJ/ac4586[6] Lorenz, R., Heuristic estimation of dust devil vortex parameters and trajectories from single-station meteorological observations: Application to InSight at Mars. Icarus, 271, 326-337 (2016). doi: 10.1016/j.icarus.2016.02.001

La espectroscopía de transmisión es una técnica fundamental para conocer la temperatura, composición y la presencia de nubes y aerosoles en las atmósferas de algunos planetas extrasolares. Cuando estos planetas reúnen una serie de condiciones adecuadas, el análisis de espectros adquiridos incluso a baja resolución puede indicar la presencia de algunas bandas de absorción y de partículas en la atmósfera. Este trabajo es el resultado de una serie de Trabajos Fin de Grado (Física) y Trabajos Fin de Máster (Ciencia y Tecnología Espacial) en la Universidad del País Vasco / Euskal Herriko Unibertsitatea.

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.

The Mars Environmental Dynamics Analyzer (MEDA) is a meteorological station onboard Mars 2020 that characterizes the near surface atmosphere. Among other sensors MEDA has 5 Air Temperature Sensors (ATS) at two altitudes: 0.85m, in the front of the rover, and 1.45m around the Remote Sensing Mast, which are azimuthally distributed so that at least one sensor is located upwind. This configuration ensures that, for most environmental conditions, the thermal contamination caused by the rover can be set apart. Local air temperatures are read with a frequency of 1 or 2 Hz, and ATS data can characterize timescales from atmospheric turbulence to the daily temperature cycle and its seasonal evolution. Here we show the daily temperature cycle at Jezero and an analysis of its seasonal evolution over the first half Martian year of the mission from Spring (Ls=6) to Autumn Equinox (Ls=180). Simultaneous ATS and winds from MEDA’s wind sensors show that, for most rover orientations, solar irradiation and winds clean environmental measurements are obtained at the 1.45m level. However, clean measurements at the 0.85m level are not always fully achieved, and a small residual thermal contamination is found at this level in many measurement sessions. The daily temperature cycle reflects the daily cycle of convection and turbulence. Strong and fast thermal oscillations start a few hours after sunrise, peak near noon, and collapse before sunset. The seasonal evolution shows a progressive increase of temperatures as summer advances, but less steep than what is retrieved at other Martian locations by previous missions. At the 0.85m level, changes in atmospheric temperatures with time-scales of a few sols correlate well with variations in local terrain properties. At the 1.45m level, similar temperature changes with timescales of a few sols are also found. We investigate whether these changes at 1.45m can be associated with changing atmospheric opacity due to dust and clouds, which are measured by other MEDA sensors and additional instruments in Perseverance. From the two altitudes sampled with ATS, and additional data from the MEDA Thermal InfraRed Sensors (TIRS), which measure ground temperature and air temperature at 40m, we can obtain the near-surface vertical temperature profile for specific sols in which thermal contamination is moderate in all sensors. This allows us to study the evolution of the diurnal convective cycle and the vertical temperature gradient. In addition, the Supercam microphone can also deduce the average air temperature from the ground up to 2.1m high thanks to sound speed measurements during Supercam’s laser zapping rocks. Therefore, it gives an additional hint into the thermal gradient. Furthermore, the amplitude of the thermal oscillations characterizes the thermal turbulence and we present the spectra of turbulence for convective and non convective hours on different moments of the mission. Finally, we will show how the measured thermal data compares with model predictions of the daily cycle of temperatures, expected magnitude of thermal oscillations, and the seasonal evolution.

The Mars 2020 Perseverance rover landed in Mars in February 2021 in Jezero crater at 18.4ºN. One of its instruments is MEDA, the Mars Environmental Dynamics Analyzer, which measures among other properties air pressure, air temperature at different levels, surface temperature from its infrared emission, and the presence of dust. The latter is provided by a set of photodiodes pointing in different directions that constitute the Remote Dust Sensor or RDS. MEDA data are acquired with a frequency of 1 or 2 Hz in data sessions that cover about 50% of a full sol allowing a full characterization of daily and seasonal cycles.Predictions before landing indicated that Jezero should be a location favoring the formation of intense vortices and dust devils in Spring to Summer. These expectations were fulfilled with frequent observations of vortices and dust devils observed with MEDA and the rover cameras. A systematic analysis of MEDA’s pressure sensor shows the close passage of convective vortices. These are detected as events that range from short and sharp pressure drops to long and deep pressure drops. Wind measurements during the vortex passage, combined with their duration, give information about the size and distance of the vortex. Many of the most intense events in terms of the pressure drop and peak winds detected have simultaneous drops of light measured with the RDS and are dust devils equivalent to those observed at much higher distances with Perseverance cameras. The combination of pressure, wind and RDS measurements largely constrain the geometry effects associated to these close passing dust devils. Some of them also have additional clear counterparts in other MEDA sensors including temperatures, which allows for an in-depth investigation of the physical properties of selected dust devils. Some events might also be captured by the SuperCam microphone, that records pressure fluctuations in the audible domain. The acoustic signal can provide insights into the short term behavior of vortices, and can contribute to the determination of the vortex physical properties. Statistics of vortices allow us to determine the probability of finding these events with the SuperCam microphone.We present results for over one Earth year (Ls=6; Feb. 2021, Northern Hemisphere Spring – Ls=180; Feb. 2022; Northern Autumn Equinox). We show the daily cycle of vortex and dust devil activity and how this has evolved from early Spring until the start of the dust storms season. We present results of the distribution of sizes of vortices and dust devils and a selection of some remarkable events. These include direct hits of dust devils passing right through Perseverance, tangential passes in which one wall of the vortex passes over Perseverance, and more distant passages of very dusty events whose diameter in some cases largely exceed 100 m. A comparison of the vortex convective activity observed at Jezero with results from a Large-Eddy-Simulations (LES) using the MarsWRF model helps us to gain insight into how the detected vortices and their properties can constrain other general properties of the atmospheric dynamics at Jezero crater.

NASA’s Mars 2020 Perseverance rover landed in Jezero Crater (~18.4ºN, 77.6ºE) on February 2021 at Ls~5º, just after the northern spring equinox. Perseverance carries the Mars Environmental Dynamics Analyzer (MEDA) instrument [1], which includes a wind sensor that is a heritage from previous sensors sent to Mars as part of the Mars Science Laboratory (MSL) and InSight missions. Those sensors allowed the characterization of the near-surface wind patterns at Gale Crater [2] and Elysium Planitia [3,4]. The wind sensor of MEDA is allowing near-surface wind patterns to be characterized at Perseverance’s landing site, thus complementing the data acquired by previous missions on the surface of Mars.Previous missions at different locations on the Martian surface observed a contribution by several mechanisms from different scales involved in the near-surface winds, including the effect of local and regional slope winds induced by topography, thermal tides, baroclinic waves and the Hadley cell, each one with a variable weight on the resulting wind patterns as a function of location, season and the presence of dust storms (e.g. [2-4] and references therein). The near-surface wind data acquired by Mars 2020 show a complex dynamics at Jezero Crater, as predicted by models (e.g. [5]). Preliminary interpretation suggests that the diurnal cycle of winds is dominated by the regional circulation mainly forced by slope winds in the Isidis basin region, which interact with the local scale circulation at Jezero and Hadley cell flows. The potential contribution by these mechanisms on the resulting wind patterns measured at Mars2020’s landing site will be presented, with a further focus on the observed wind variability supported by probabilistic models. References:[1] Rodriguez-Manfredi et al. (2021), SSR, 217(48). [2] Viúdez-Moreiras et al. (2019), Icarus, 319, 909-925. [3] Banfield et al. (2020), Nat.Geo, 13, 190-198. [4] Viúdez-Moreiras et al. (2020) JGR-Planets, 125, e2020JE006493. [5] Newman et al. (2021) SSR, 217(20).

On top of listening to laser shots, rover sounds and the Ingenuity rotorcraft, SuperCam’s Mars microphone has recorded over 7 hours of ambient background noise on Mars. These background recordings contain signal due to the Martian wind. Through a comparison to the meteorological data recorded by the MEDA (Mars Environmental Dynamics Analyzer), we can determine the relationships between the microphone data, the wind and the atmospheric stability. Based on these relationships, we have determined a way to estimate the wind speed using the microphone through Gaussian process regression, a machine learning technique. Owing to the sampling rate of 25 000 samples per second, the microphone data can be used to examine Mars’ atmospheric dynamics at high frequencies, as yet unexplored on Mars. We will demonstrate how the wind speed estimates from the microphone provide an assessment of turbulence at fine scales, shedding light on the dissipative regime on Mars. One particularly interesting signal recorded by the microphone was a dust devil, which had fast varying winds within the walls of its vortex and signal from dust particles hitting the rover. Combining the microphone data with information from the MEDA sensors and navigation camera (Navcam) images enabled a full parameterization of this event.

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

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