VORTEX AND DUST DEVIL ACTIVITY ON JEZERO CRATER FROM
MARS2020/MEDA DATA AND PHYSICAL CHARACTERIZATION OF
SELECTED EVENTS
R. Hueso1 (ricardo.hueso@ehu.eus), A. Munguira1, A. Sánchez-Lavega1, C. E. Newman2, M. Lemmon3, T. del
Río-Gaztelurrutia1, M. Richardson2, V. Apestigue4, D. Toledo4, A. Vicente-Retortillo5, M. de la Torre-Juarez6, J.
A. Rodríguez-Manfredi5, L. K. Tamppari6, I. Arruego4, N. Murdoch7, G. Martinez8, S. Navarro5, J. GómezElvira5, M. Baker9, R. Lorenz10, J. Pla-García5, A.M. Harri11, M. Hieta11, M. Genzer11, J. Polkko11, I.
Jaakonaho11, T. Mäkinen11, A. Stott7, D. Mimoun7, B. Chide12, E. Sebastian5, D. Viudez-Moreiras5, D.
Banfield13, A. Lepinette-Malvite5
1. UPV/EHU, Bilbao, Spain, 2. Aeolis Research, Chandler, AZ, USA, 3. Space Science Institute, College Station, TX, USA, 4. Instituto Nacional de Técnica Aeroespacial (INTA), Madrid, Spain, 5. Centro de Astrobiología (INTA-CSIC), Madrid, Spain, 6. Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA,
USA, 7. Institut Supérieur de l’Aéronautique et de l’Espace (ISAE-SUPAERO), Université de Toulouse, Toulouse, France, 8. Lunar and Planetary Institute, Houston, TX, USA, 9. Smithsonian Institution, Washington, DC,
USA, 10. Johns Hopkins Applied Physics Laboratory, Laurel, MD, USA, 11. Finnish Meteorological Institute,
Helsinki, Finland, 12. Los Alamos National Laboratory, Los Alamos, NM, USA, 13. Cornell Center for Astrophysics and Planetary Science, Cornell University, Ithaca, NY, USA.
tion event.
MEDA
The Mars 2020 Perseverance rover landed in
Mars in February 2021 in Jezero crater at 18.4ºN.
The Mars Environmental Dynamics Analyzer
(MEDA) instrument [1] on Mars 2020 measures environment parameters such as air pressure, horizontal
winds, air temperature at different levels, surface
temperature from its infrared emission, and the presence of dust from photodiodes pointing in different
directions. MEDA acquires data typically over 50%
of a full sol with a cadence of 1 Hz in most sensors
and 0.5 Hz in a few cases. After more than 360 sols
in Mars, the data allows to explore the changing dynamics of the Martian atmosphere from northern
Spring (Ls=6º, sol 1) to northern Autumn Equinox
(Ls=180º, sol 361) and beyond.
Vortices, Dust Devils and other pressure drops
Predictions before landing [2] suggested that
Jezero is a location where intense vortices and frequent dust devils form. MEDA data, as well as dust
devil surveys and movies obtained by the different
cameras on Perseverance, confirm those predictions
with frequent observations of vortices and dust devils
[3].
The passage of convective vortices close to Perseverance produces pressure drops of varying duration and intensity that are characterized from MEDA
data and follow a daily cycle with activity peaking at
noon. Distinct weak vortices of 0.3-0.5 Pa start in the
morning at 08-09 am and they increase in number
and strength as the sol progresses, with some pressure drops larger than 6 Pa close to noon on particular sols. The typical duration of the pressure drop is
30 s but there are long events that exceed durations
of 100 s. Figure 1 shows an example of a long dura-

Figure 1: A long and intense pressure drop found on
MEDA pressure data (red curve) and its fit with a
Gaussian (blue) or Lorenzian function (green) with
relevant physical parameters. The horizontal grey
line shows a common detection threshold in vortex
studies of 0.5 Pa.
Besides vortices, there are long pressure drops
where the combination of pressure and winds show
strong turbulence, and where the multi-sensor characterization of the local environment by MEDA suggests the passage of the boundaries of convective
cells [3]. These long and turbulent pressure drops
also peak in their activity close to noon. In most sols,
night-time pressure drops are only found irregularly
and are much weaker than the daytime activity.
We will discuss the seasonal variation of the daily cycle of vortices and convective cells. In addition,
short clusters of vortex and pressure drops are also
concentrated in particular ranges of sols, meriting a
comparison of the location of these clusters with the
properties of the varying terrain covered by Perseverance in its traverse over Jezero.
Dust Devils
Many of the vortices detected in pressure show a
simultaneous drop of light detected by the photodiode dust sensors that point to the top. These events

constitute close encounters with dust devils. We find
a clear relation between the strength of the vortices
from the intensity of the pressure drop and the frequency in which they bring dust. At noon, when vortices are more intense and frequent (1.1 event with
P>0.5 Pa per hour), up to a 25% of all vortices with
a pressure drop larger than 0.5 Pa have detectable
dust. Disregarding local time constrains, at least 78%
of all events with P>2.0 Pa are dusty, as well as all
events with a pressure drop P>3.2 Pa. The largest
drop in light from the RDS Top 7 detector occurred
for a vortex with P=4.5 Pa and a duration of 100 s
that showed a decrease of 25% of the light measured
by the photodiodes in the top of the rover. The example shown in Figure 1 was accompanied by a reduction in the signal measured by the RDS Top 7
detector of 8%.
Windy vortices and geometry of encounters
Intense pressure drops also show their signature
in winds. Due to operational constrains, the wind
sensors are not always on and obtaining data when
the rest of MEDA is working. Nonetheless, there is a
long number of vortices detected in pressure and
with simultaneous wind data that allows constraining
the geometry of the encounter. Figure 2 shows an
example of one of these events with a wind intensity
profile that is compatible with a near direct encounter
of the vortex with Perseverance.

Figure 2: An example of a dust devil detected with
an intense pressure drop (black curve, left axis), a
strong decrease of light in the RDS Top 7 detector
(blue line rightmost axis) and winds (purple line and
right axis). The double peak structure of the winds
and small central values are indicative of a very close
encounter.
In close encounters with vortices like the case
shown in Figure 2, the combination of pressure drop
duration and background wind intensity outside the
vortex allows to characterize the vortex diameter,
which in this case is about 20 m. In the statistical
analysis of dust devils with simultaneous wind data,
the distance scale measured by this metric lies in the
range of 10-400 m, with a median value of 60 m [3].
Multi-sensor characterization of dusty windy
vortices
The sample of dust devils with good wind data
offers an excellent opportunity to characterize specific events. Individual events can be examined in comparison with models of drifting vortices [4] that

largely constrain the physical characteristics of individual vortices such as their diameter, distance at
closest approach and true pressure drop at their centers. Some of the closest approaches have clear counterparts in the temperatures measured by the 5 Air
Temperature Sensors located in different locations of
the rover’s mast and its front. These thermal counterparts generally imply higher temperatures of +5 K
with respect to their environment.
We will present examples of the multi-sensor
characterization of selected dust devils including dust
devils passing right through Perseverance, tangential
passes in which one wall of the vortex passes over
Perseverance, and more distant passages of large and
very dusty events.
Comparison with LES simulations and activity
during a dust storm
MEDA is producing a treasure trove of observations of vortices and dust devils. The distinct different response of dust devils during a recent dust storm
[5] will be discussed in comparison with the seasonal
evolution of vortex activity.
Finally, in order to gain further insight on convective vortices and convective cells, we are comparing the pressure drops detected in the MEDA pressure data with results from a Large-Eddy Simulation
using the MarsWRF model of Jezero crater with 10
m resolution, where convective cells and vortices are
observed [3].
While the vortices and dust devils here studied
are only those that pass close enough to Perseverance
to cause a detectable pressure perturbation, additional dust devils are detected at a range of distances
from MEDA photodiodes and the different imaging
instruments. The inter comparison of those rich datasets, available only for Jezero, will undoubtfully
help to advance our understanding of the role of dust
devils in the Martian dust cycle.
References:
[1] Rodríguez-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, 2021.
[2] Newman, C.E. et al. Multi-model Meteorological
and Aeolian Predictions for Mars 2020 and the
Jezero Crater Region, Space Science Reviews, 217,
2021.
[3] Newman, C.E., Hueso, R., Lemmon, M. et al.,
The dynamic atmospheric and aeolian environment
of Jezero crater, Mars, Science Advances (in press).
[4] Lorenz, R. Heuristic estimation of dust devil vortex parameters and trajectories from single-station
meteorological observations, Icarus, 271, 2016.
[5] Lemmon, M. et al. Dust, sand and winds within
an active Martian storm in Jezero crater, 7 th MAMO
conference.