OVERVIEW OF NEAR-SURFACE ATMOSPHERIC PROCESSES AT JEZERO
FROM MEDA OBSERVATIONS
M. de la Torre Juárez, Jet Propulsion Laboratory-California Institute of Technology, USA (mtj@jpl.nasa.gov),
J.A Rodríguez-Manfredi, CAB, INTA, Madrid, Spain, G. Martínez, LPI, Houston, TX, USA, C.E. Newman,
Aeolis Research, Chandler, AZ, USA, M.T. Lemmon, SSI, College Station, TX, USA, R. Hueso, UPV/EHU, Bilbao,
Spain, A. Munguira, UPV/EHU, Bilbao, Spain, L.K. Tamppari, Jet Propulsion Laboratory-California Institute of
Technology, USA, A. Sánchez-Lavega UPV/EHU, Bilbao, Spain, V. Apéstigue, INTA, Madrid, Spain, I.
Arruego, INTA, Madrid, Spain, D. Banfield, Cornell, Ithaca, NY, USA; NASA-AMES Flight Center, USA, J.
Boland, Jet Propulsion Laboratory-California Institute of Technology, USA, P.G. Conrad, Carnegie Institution,
USA, T. del Río, UPV/EHU, Bilbao, Spain, A. de Vicente-Retortillo, CAB, INTA, Madrid, Spain, M. DomínguezPumar, UPC, Spain, E. Fischer, Univ. Michigan, Ann Arbor, USA, M. Genzer, FMI, Finland, S. Giménez, CAB,
INTA, Madrid, Spain, J. Gómez-Elvira, INTA, Madrid, Spain, F. Gómez, CAB, INTA, Madrid, Spain,, S.D.
Guzewich, NASA Goddard Space Flight Center, Greenbelt, MD, USA, A.-M. Harri, FMI, Finland, M. Hieta, FMI,
Finland, V. Jiménez, UPC, Spain A. Lepinette, CAB, INTA, Madrid, Spain, M. Marín, CAB, INTA, Madrid, Spain,
C. Martín-Rubio, CAB, INTA, Madrid, Spain, T. Mcconnochie14, A. Molina, CAB, INTA, Madrid, Spain, F.
Montmessin, LATMOS, France, L. Mora-Sotomayor, CAB, INTA, Madrid, Spain, S. Navarro, CAB, INTA,
Madrid, Spain, V. Peinado, CAB, INTA, Madrid, Spain, S. Pérez-Hoyos, UPV/EHU, Bilbao, Spain,, J. Pla-García,
CAB, INTA, Madrid, Spain; SSI, Boulder, CO, USA, J. Polkko, FMI, Finland, J. Romeral, CAB, INTA, Madrid,
Spain, C. Romero, CAB, INTA, Madrid, Spain, H. Savijärvi, Univ. Helsinki, Finland, E. Sebastian, CAB, INTA,
Madrid, Spain, M.D. Smith, NASA Goddard Space Flight Center, Greenbelt, MD, USA, R.J. Sullivan, Cornell,
Ithaca, NY, USA, C. Tate, Cornell, Ithaca, NY, USA, D. Toledo Carrasco, INTA, Madrid, Spain, J. Torres, INTA,
Madrid, Spain,, R. Urquí, CAB, INTA, Madrid, Spain, D. Viúdez-Moreiras, CAB, INTA, Madrid, Spain, M. Wolff,
SSI, College Station, TX, USA, M.P. Zorzano, CAB, INTA, Madrid, Spain, S. Zurita, CAB, INTA, Madrid, Spain,
and the MEDA team.
Introduction: Perseverance landed on Jezero with the
most complete suite of environmental sensors sent to
date to another planet. These sensors are on the Mars
Environmental
Dynamics
Analyzer
(MEDA),
MastCam-Z, SuperCam spectrometers and, finally,
several microphones [1,2,3]. MastCam-Z, the rover
engineering cameras, and MEDA’s SkyCam combined
measure the dust opacity and physical aerosol
properties on time scales from seconds to diurnal,
seasonal, and annual. MEDA’s atmospheric sensors
characterize surface pressure, air temperature at three
heights, surface temperature, night time relative
humidity, wind speeds and directions, and radiative
fluxes. This is a summary of MEDA observations to
date.
Temperature cycle: While showing some
response to surface temperature changes with location
and the associated variations in thermal inertia, Fig. 1a
shows that the air temperature has changed little as a
function of Ls since landing [4], and its seasonal trend
is more stable than other missions, similar to VL1’s
behavior.
MEDA shows in Fig 1b the ability to track the
evolution of temperatures at four heights: the surface,
85 cm, 145 cm, and an atmospheric layer spanning
from about rover height m to 200 m, with a

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contribution peak at 40 m day and night. This opens up
the ability to measure the vertical distribution of the
thermal signatures from dust devils, as well as the
associated changes in buoyancy. This observation

(a)
(b)

(b)
(b)

Figure 1. (a) Average sol temperature for Viking Landers VL1,
VL2, Mars Pathfinder MPF, Phoenix PHX, Curiosity MSL and
M2020. (b) Evolution of MEDA daily average temperatures at 4
heights.

helps identify the passage of convective plumes, when
the density at low heights coincides with the density at
40 m, see Figure 2, and sometimes separate those
above 40 m from lower ones. Following the time when
the signal of convective plumes enables and its relation
to dust events, allows to link convective cells to the
passage of dust devils [5]. Figure 2 shows the density
at several heights during the passage of a dust object.

(a)
(b)

(b)
(b)

(c)
(b)

Figure 2. Air density estimates in g/m3 at the surface (olive
green), 85cm (blue), 145cm (green), and 40m (magenta)
above the surface overlaid with surface pressure (blue
symbols) during the passage of a pressure eddy drop. It
shows the vertical signature of the passage of convective
plumes vertical mixing and reduce the density differences
from 40 m (green) to that at 145cm and 85cm (red).

Pressure cycle: The pressure cycle is following its
seasonal pattern and some more focus has been set on
the amplitude of pressure tides. They respond to
changes in opacity (Fig. 3a) measured by the SkyCam,
MCAM-Z and the engineering cameras. A first
noticeable difference was the smaller amplitude of
Jezero’s diurnal tide when compared with Gale [6] or
Viking [7,8], Fig. 3b. While the behavior at Jezero was
reasonably well predicted by the models intercompared
in [9], there are differences in the amplitude and
especially the timing of the disruptions caused by dust
storms, and also to the seasonal cycle of the polar cap
sublimation and growth peaks.
Another visible difference appears in the
comparison to the pressure cycle observed by
Curiosity’s Rover Environmental Monitoring Station
(REMS) at Gale during the same period. This
difference is largely due to the local characteristics of
how the lateral hydrostatic adjustment to the
topography interacts with the exchanges of air mass
between the interior and exterior of the basin [10]. On
Gale the amplitude of the diurnal pressure tide
remained larger than the semidiurnal pressure tide.
Both were slightly higher than that of MEDA, the
diurnal had a different response to a dust storm near
Ls~150º, and the convexity of the semidiurnal tide had
opposite sign at Jezero than over Gale between Ls~30
and Ls~140º.

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Figure 3. Temporal evolution from Ls 10º to 170º for (a)
Diurnal cycle of aerosol opacity at 699 nm before noon
(blue) and after noon (red); (b) response of the
normalized diurnal, semidiurnal, and terdiurnal tide to
the dust cycle on Jezero; and (c) same pressure tide
amplitudes at Gale.

Aeolian Processes: MEDA wind observations [see
5] are consistent with the model predictions [8,11] that
daytime and nighttime wind directions respond to
different mechanisms. The most frequent wind
orientation during daytime is consistent with the
regional models of synoptic scale winds. At night the
local Jezero slope topographic flows seem to dominate
over the synoptic meteorology.
The two different wind regimes leave a different
mark in the average wind speeds, shown in Figure 4,
and the times when the wind is most unstable (top of
Figure 4). During the daytime convective regime, that
is between ~9 am LTST and ~15 LTST, wind speeds
are intense and so are their standard deviations.
However, the strongest winds appear in the evening
transition, around 15 to 18 LTST, as the surface is
cooling down. After a calm period of about 2 hours,
new jets form and last from around 20 LTST to
midnight and into the early hours of the new sol. These
nighttime winds don’t seem to generate as strong
fluctuations as those driven by daytime convection.
Jezero’s abundance of eddy pressure signatures and
wind surges accompanied by dust lifting stands out
from other Mars locations [11]. Jezero accumulates a
high frequency of dust devils, and dust clouds rising
and flying over the rover. This characteristic of Jezero
is providing new aspects of the physical processes
involved in active dust lifting.

Figure 4. Top: observed wind speed fluctuations, measured
as standard deviation of wind speeds, and; Bottom: 5-minute
averaged wind speeds marking different dynamical regimes
in daytime and evening.

Local hydrological cycle: The Local hydrological
cycle combined with the radiation cycle are key
components of astrobiological models for Mars, as
well as processes that affect alteration and
geochemistry. MEDA relative humidity measurements
follow an approach that can be compared to similar
sensors flown to other locations on Phoenix and
Curiosity’s REMS. SuperCAM adds information on
total water column that can be compared to surface
MEDA’s observations. As of this writing Jezero
appears as a drier location even under a higher water
column content.
Another observation is a night time humidity cycle
with several peaks that was not predicted [11] and
could be related to wind transport of water or to
exchanges with the surface. Understanding the
potential reasons for this result requires a longer data
record that enables to separate what are robust, long
lasting effects that could be associated to latitude,
altitude, or topography, and what may be seasonal
effects. Therefore more constant monitoring is needed
and key in helping constrain what mechanisms are
more intense at Jezero than at Gale. Thus far, the lower
nighttime relative humidity at Jezero for the same
period raises the possibility of a more active diurnal
exchange process between the atmosphere and the
surface rather than this effect being purely seasonal or
latitudinal influence.
Radiative cycle: The ability to regularly measure
opacities several times every sol with the Radiation
and Dust Sensor (RDS) is not only capturing the
evolution of atmospheric opacity, but offers a color
index that can separate ice from dust aerosols. It has
unveiled that the morning hours meet a slightly more

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opaque atmosphere in the morning hours than in the
afternoon since M2020 landed [figure 3a and reference
12]. The photodiodes on the RDS, covering from the
UV into the near IR have found signatures of early
morning clouds [13]. The Thermal Infrared Sensor
(TIRS) has confirmed those as well and the Thermal
Infrared signatures of the evolution and possible
growth of night time clouds.
Additional, channels on the TIRS enable to
measure in-situ the radiative energy balance at the
surface, its albedo on a small scale, and provide ground
validation to satellite measurements over Jezero.
Energy balance estimates combined with
measurements of wind speeds and temperature profiles
are also being used to infer the diurnal cycle of eddy
heat fluxes. The turbulent parameters associated to this
heat diffusivity are required to model the exchanges of
heat between the surface and the atmosphere that force
the local dynamics and transport near the surface.
Summary and Future Work: Jezero is
reinforcing the different types of environments that one
can find on Mars. It is exhibiting unique temperature
and pressure cycles attributable to a combination of
topographic and latitudinal effects. The ability to
capture vertical temperature profiles is enabling for the
first time to explore the vertical response of the
atmosphere to passing eddies and how the boundary
layer responds to different atmospheric dust loads. All
of it on a region of Mars where we might land again in
the future, thereby providing useful information for the
engineering and design of future mission to Jezero.
Being at a different location from InSight’s and
Curiosity, it forms a network of comparable
atmospheric sensors that capture how the large-scale
circulation simultaneously affects different parts of the
red planet. A longer data record and the diverse
sensors on MEDA is becoming useful to understand
how the global circulation impacts the processes
observed at different latitudes and longitudes.
Last, Perseverance’s instruments inform the
context of other instruments data, the rover
engineering activities, and Ingenuity helicopter flight
decisions. We hope that MEDA and Perseverance
sensors enable novel measurements that we are only
starting to discover, like now possible to measure the
response of near-surface vertical temperature profiles
to dust events, or to the full solar cycle, the cycles of
net radiative balance at the surface, or more technical
in-situ observations as ground truth for orbital
instruments, like direct estimation of thermal inertia
and broadband albedo across Perseverance’s traverse,
or the evolution of magnitudes relevant for MoninObukhov parameterizations.

Acknowledgments: This work was performed
partially at the Jet Propulsion Laboratory/Califonria
Institute of Technolgy under a contract with NASASTMD and SMD, and also funded by the Spanish
MINECO under several projects. MEDA calibrated
measurements for the first 179 sols of the Mars 2020
mission, Viking, Phoenix, Mars Pathfinder, and REMS
data up to sol 3192 are available at the NASA
Planetary Data System Atmospheres node. Model
predictions were provided by J. Wilson, M. Collins, C.
Newman [9].
References: [1] Rodríguez-Manfredi et al. Space
Sci. Rev., 217.3 (2021) [2] Bell et al. Space Sci. Rev.,
217.3. (2021) [3] Wiens et al. Space Sci. Rev., 217.3.
(2021) [4] Hueso et al. Fall AGU (2021). [5] Newman
et al. MAMO 2022. [6] Guzewich et al. Icarus, 268
(2016). [7] Tillman et al. JGR, D8 (1988). [8] Zurek &
Leovy Science, 213 (1981). [9] Newman et al. Space
Sci. Rev. 217.3 (2021). [10] Richardson & Newman
Planet. Space Sci, 164 (2018). [11] Pla-García et al.
Space Sci. Rev. (2021) [12] Rodríguez-Manfredi et al.
Fall AGU (2021). [13] Toledo et al. Fall AGU (2021).

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