Winds at the Mars 2020 Landing Site: 1. Near‐Surface Wind Patterns at Jezero Crater

Viúdez‐Moreiras, Daniel; Lemmon, M. T.; Newman, Claire; Guzewich, Scott D.; Mischna, M. A.; Gómez‐Elvira, Javier; Herkenhoff, K. E.; Sánchez‐Lavega, Agustín; Juárez, Manuel de la Torre; Rodríguez‐Manfredi, J. A.; Lorenz, Ralph D.; Pla‐García, Jorge; Hueso, R.; Richardson, M. I.; Tamppari, L. K.; Smith, M. D.; Apéstigue, Víctor; Toledo, Daniel; Fraeman, A. A.

doi:10.1029/2022je007522

Cited by 13 publications

(24 citation statements)

References 70 publications

(140 reference statements)

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“…In the LES, distant and long‐duration vortices are detected because of the clean pressure signal and the regular background winds imposed in the model. However, in the MEDA pressure data at Jezero, a measurement noise of 0.1 Pa combined with turbulent fluctuations in pressure (Sánchez‐Lavega et al., 2022), variations in wind speed and direction (Rodriguez‐Manfredi et al., 2023; Viúdez‐Moreiras et al., 2022) make detections of distant events more difficult to detect. Additional factors, such as the variations in spatial scales of a few meters of terrain roughness, inclination, thermal inertia, and albedo might also contribute to produce a more turbulent atmosphere than the one that can be simulated by the LES.…”

Section: Comparison With Les Resultsmentioning

confidence: 99%

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

et al. 2023

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Daytime convective vortices are common on Mars and Earth (Balme & Greeley, 2006). They constitute one of the various phenomena that develop in the Planetary Boundary Layer (PBL) of both planets, but are much more common and can be an order of magnitude larger on Mars due to the more extended PBL depth (Balme & Greeley, 2006). Dusty convective vortices, or dust devils (DDs), are vortices that have raised dust from the

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Section: Comparison With Les Resultsmentioning

confidence: 99%

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

et al. 2023

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“…This is caused by environmental winds at that time of the day blowing across the rover and injecting thermal perturbations from the rover to the air sampled by the ATS at 1.45 m. Nighttime values of σ T in Figure 4a are also enhanced by thermal perturbations from the RTG (see Figure S3 in Supporting Information S1) and are apparent at 20hr, 23hr, 01hr and 02hr in Figure 4a. At night, the wind primarily blows from the N/NW/W (Newman et al, 2022;Viúdez-Moreiras, Lemmon, et al, 2022) (this varies with time of sol and from sol to sol). Hence the nighttime RTG-induced perturbations are most evident when the rover heading is to the S/SE/E, except between 01 and 05 LTST when winds are weak with very variable directions.…”

Section: Temperature Fluctuationsmentioning

confidence: 99%

Near Surface Atmospheric Temperatures at Jezero From Mars 2020 MEDA Measurements

et al. 2023

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The Mars Environmental Dynamics Analyzer instrument on Mars 2020 has five Atmospheric Temperature Sensors at two altitudes (0.84 and 1.45 m) plus a Thermal InfraRed Sensor that measures temperatures on the surface and at ∼40 m. We analyze the measurements from these sensors to describe the evolution of temperatures in Jezero up to mission sol 400 (solar longitude LS = 13°–203°). The diurnal thermal cycle is characterized by a daytime convective period and a nocturnal stable atmosphere with a variable thermal inversion. We find a linear relationship between the daytime temperature fluctuations and the vertical thermal gradient with temperature fluctuations that peak at noon with typical values of 2.5 K at 1.45 m. In the late afternoon (∼17:00 Local True Solar Time), the atmosphere becomes vertically isothermal with vanishing fluctuations. We observe very small seasonal changes in air temperatures during the period analyzed. This is related to small changes in solar irradiation and dust opacity. However, we find significant changes in surface temperatures that are related to the variety of thermal inertias of the terrains explored along the traverse of Perseverance. These changes strongly influence the vertical thermal gradient, breaking the nighttime thermal inversion over terrains of high thermal inertia. We explore possible detections of atmospheric tides on near‐surface temperatures and we examine variations in temperatures over timescales of a few sols that could be indicative of atmospheric waves affecting near‐surface temperatures. We also discuss temperatures during a regional dust storm at LS = 153°–156° that simultaneously warmed the near surface atmosphere while cooling the surface.

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“…The nighttime humidity fluctuations are due to the wind capable of creating turbulence sufficient to bring humidity toward lower altitudes. The great wind variability observed by Mars 2020 at night/early morning was consistent with an increase in mechanical turbulence caused by downslope convergent flows on the crater floor (Viúdez‐Moreiras, de la Torre, et al., 2022; Viúdez‐Moreiras, Lemmon, et al., 2022). Figure 10 shows continuous‐mode observations of the nights of sols 330/331 and 399/400.…”

Section: Meda‐hs Observations and Preliminary Analysesmentioning

confidence: 67%

Initial Results of the Relative Humidity Observations by MEDA Instrument Onboard the Mars 2020 Perseverance Rover

et al. 2023

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The Mars 2020 mission rover "Perseverance", launched on 30 July 2020 by NASA, landed successfully 18 February 2021 at Jezero Crater, Mars (Lon. E 77.4509° Lat. N 18.4446°). The landing took place at Mars solar longitude Ls = 5.2°, close to start of the northern spring. Perseverance's payload includes the relative humidity sensor MEDA HS (Mars Environmental Dynamics Analyzer Humidity Sensor), which operations, performance, and the first observations from sol 80 to sol 410 (Ls 44°-210°) of Perseverance's operations we describe. The relative humidity measured by MEDA-HS is reliable from late night hours to few tens of minutes after sunrise when the measured humidity is greater than 2% (referenced to sensor temperature). Data delivered to the Planetary Data System include relative humidity, sensor temperature, uncertainty of relative humidity, and volume mixing ratio (VMR). VMR is calculated using the MEDA-PS pressure sensor values. According to observations, nighttime absolute humidity follows a seasonal curve in which release of water vapor from the northern cap with advancing northern spring and summer is visible. At ground level, frost conditions may have been reached a few times during this season (Ls 44°-210°). Volume mixing ratio values show a declining diurnal trend from the midnight toward the morning suggesting adsorption of humidity into the ground. Observations are compared with an adsorptive single-column model, which complies with observations and confirms adsorption. The model allows estimating daytime VMR levels. Short-term subhour timescales show large temporal fluctuations in humidity, which suggest vertical and spatial advection. Plain Language SummaryThe Mars 2020 mission rover "Perseverance" landed successfully on 18 February 2021 at Jezero Crater, Mars. The rover's payload includes a versatile instrument suite which includes a relative humidity sensor, whose observations for the first 410 Martian days are described here. The observations show how the lowest level of atmosphere is generally dry but still exceeding saturation is feasible because of cold nights. Sensor operations and accuracy estimates are presented. Relative humidity together with MEDA pressure and air temperature observations allow calculating absolute water vapor content of air at the sensor level at nighttime. Humidity observations are also compared with models describing water vapor adsorption and desorption into and out from soil. The results show how atmospheric humidity at the rover's site experiences large subhour variability. Humidity observations help to understand interchange of humidity between the soil and the atmosphere. Water is mandatory for life, such as on earth, thus understanding these water cycle processes better are important for evaluating possibilities of past and current habitability of Mars. Perseverance is also collecting samples which maybe returned to Earth one day. Knowledge of the conditions at the times when samples were collected maybe useful.

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Winds at the Mars 2020 Landing Site: 1. Near‐Surface Wind Patterns at Jezero Crater

Cited by 13 publications

References 70 publications

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

Convective Vortices and Dust Devils Detected and Characterized by Mars 2020

Near Surface Atmospheric Temperatures at Jezero From Mars 2020 MEDA Measurements

Initial Results of the Relative Humidity Observations by MEDA Instrument Onboard the Mars 2020 Perseverance Rover

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