CHANGES IN SURFACE ALBEDO INDUCED BY DUST DEVILS AND
THE MY 36 LS155 DUST STORM AT JEZERO CRATER
A. Vicente-Retortillo1,2, G.M. Martínez3, M. T. Lemmon4, R. Hueso5, R. Sullivan6, C. E. Newman7, E. Sebastián1, D. Toledo8, V. Apéstigue8, I. Arruego8, A. Munguira4, A. Sánchez-Lavega5, L. Mora-Sotomayor1,
T. Bertrand9, L. K. Tamppari10, M. de la Torre Juárez10, J.-A. Rodríguez-Manfredi1, 1Centro de Astrobiología (INTA-CSIC), Madrid, Spain (adevicente@cab.inta-csic.es) , 2University of Michigan, Ann Arbor, MI,
USA, 3Lunar and Planetary Institute, USRA, Houston, TX, USA, 4Space Science Institute, Boulder, CO, USA,
5
Universidad del País Vasco (UPV/EHU), Bilbao, Spain, 6CCAPS, Cornell University, Ithaca, NY, USA, 7Aeolis
Research, Chandler, AZ, USA, 8Instituto Nacional de Técnica Aeroespacial (INTA), Madrid, Spain, 9LESIA,
Meudon, France, 10Jet Propulsion Laboratory/California Institute of Technology, Pasadena, CA, USA.

Introduction:
Since February 2021, the environmental conditions at Jezero Crater have been monitorized by
MEDA, the suite of meteorological sensors onboard
the Mars 2020 Perseverance rover [1]. Simultaneous
measurements from the Thermal and Infrared Sensor
(TIRS), the Radiation and Dust Sensor (RDS), the
Pressure Sensor and the Wind Sensor allow studying
dust lifting at the Martian surface by analyzing an
unprecedented set of magnitudes, including high
frequency measurements (1 – 2 Hz) of surface
broadband albedo and temperature, wind speed and
direction, and pressure. In addition, Mastcam-Z and
Navcam images [2,3] provide additional context and
support albedo variations detected by MEDA by
showing changes in the surface caused by dust lifting
and sand transport.
Jezero Crater was affected by a dust storm between sols 313 and 318 of the mission (Ls ~155º),
which caused a significant change in environmental
conditions. We have classified the albedo changes in
two categories: rapid variations that occurred during
typical relatively quiescent conditions, and changes
induced by the dust storm [4].
Instrument description and methodology:
TIRS [5] comprises five channels which measure
downward (IR1) and upward (IR4) longwave (6.5 –
30 µm) radiation, atmosphere temperature (IR2),
reflected shortwave (0.3 – 3 µm) radiation (IR3), and
surface temperature (IR5). Channels IR3, IR4 and
IR5 cover an area of about 3 m2 located at less than 4
meters from the RTG [1]. The RDS has two sets of
photodiodes. One of them points towards the zenith
and includes a detector (TOP7) with a hemispheric
field of view that measures between 190 and 1100
nm [1]. We use the ratio between TIRS IR3 and RDS
TOP7 measurements as a proxy for surface albedo
(note that the values do not correspond to the actual
albedo because TIRS and RDS measure in different
spectral bands, but it is valid for our purpose of analyzing changes). The wind sensor consists of two
booms at above 1.5 m above the ground, separated
by 120º in azimuth to mitigate hardware wind interferences [1].

Albedo changes induced by dust devils:
MEDA measurements show the passage of numerous convective vortices close to the rover, which
are detected as pressure drops [6]. Some of these
drops are accompanied by a decrease in shortwave
radiation, indicating that there was dust lifting by the
convective vortex.
Simultaneous measurements of radiation and
wind measurements suggest that some of the dust
devils passed over the rover [7]. Here we have analyzed these measurements to identify the dust devils
that are more likely to have affect the closest surroundings of the rover and we have analyzed the
albedo in the surface portion covered by TIRS before
and after the passage of the dust devil.
We have identified more than 40 dust devils that
could have potentially altered the surface albedo
during the first 350 sols of the Mars 2020 mission.
We have observed that these dust devils cause a transient decrease in the surface temperature measured
by TIRS [8]. The analysis of the events with a larger
effect on surface temperature reveals that the decrease in temperature is not always accompanied by
a change in surface albedo. This highlights the importance of dust availability and mobility at the surface.

Figure 1. Change in surface albedo (red) and
wind speed (green) caused by the passage of a dust
devil on sol 57 of the Mars 2020 mission.

Figure 1 shows the change in surface albedo
caused by a dust devil that affected Perseverance’s
location at 11:16 LMST on sol 57. In this case, the
albedo decreased by around 1.5%.
Wind speeds and terrain properties. Determining
a wind speed threshold for dust lifting or sand
transport is a challenging task: first, it depends on
particle availability and mobility at the surface,
which depends on the rover location; and second,
wind speeds are not measured at the exact region
where observed dust lifting occurs; in this regard, the
analysis of dust lifting and sand transport through
surface albedo changes with MEDA minimizes potential uncertainties due to the small distance between the wind sensor booms and the TIRS target.
Despite these difficulties, it is possible to estimate an upper bound for which we observe dust lifting and a subsequent albedo change under favorable
conditions. The most significant albedo changes occurred with peak wind speeds above 15 m/s, but it is
not possible to discard dust lifting with lower wind
speeds.
It is important to notice, however, that strong
winds associated with some intense dust devils have
not altered the surface. As an example, an intense
dust devil on sol 173 caused winds at the rover’s
location above 20 m/s, but it did not cause detectable
changes in surface albedo.
Albedo changes induced by the dust storm:
Between sols 313 and 318 of the mission, Jezero
crater was affected by a dust storm. During this
storm, dust opacities measured by Mastcam-Z increased from less than 0.4 on sol 312 to almost 1.4
on sol 316, decreasing again to 0.4 on sol 319 (see
Figure 2). Perseverance remained at the same location between sols 287 and 328, providing a unique
opportunity to track surface albedo changes during
40 sols, including those before, during and after the
storm.

Figure 2. Change in surface albedo at 13 LMST
(dark orange) and dust opacity (gray) between sols
287 and 328.
Figure 2 shows the temporal evolution of the surface albedo between sols 287 and 328 at 13 LMST (a
similar behavior is observed at other times). The

most remarkable feature shown in this figure is the
strong darkening of the surface induced by the dust
storm: there was a 17% decrease in surface albedo
between sols 315 and 319; the largest sol-to-sol variation occurred between sols 315 and 316, when the
albedo decreased by around 11%. In contrast, the
albedo remained stable both before and after the
storm. There are two secondary variations in surface
albedo, which are associated with two enhanced
opacity events on sols 296 and 298.
Analysis of the albedo changes. In this section,
we use Mastcam-Z images of the surface observed by
TIRS to further assess the changes induced by the
dust storm.
Figure 3 shows a comparison of images of the
portion of the surface observed by TIRS before (top)
and after (bottom) the dust storm. One of the most
apparent changes can be found in the wheel tracks.
When rover wheels press on the soil as the wheels
roll along, they mold the soil into track impressions.
This molding process destroys any light surface cohesion/crust while reconfiguring the grains into
molds to closely match the intricate shape of the
wheel tread. The composition of the molded track
material remains virtually unaltered, but original
appearance is replaced by a sort of very light artificial cohesion. These tracks appear to be fainter in
the lower panel, suggesting that all of the fines (dust,
silt, sand) making up the molded tracks were mobilized.

Figure 3. Comparison of portions of Mastcam-Z
projections corresponding to the TIRS field of view
before (top) and after (bottom) the dust storm.
In addition, there appears to be an overall darkening, which is particularly notorious at regions show-

ing a higher albedo contrast with the sand. Variations
in sand and dust cover of the bright rock in the field
of view could also have contributed to the observed
decrease in albedo.
Effect of the albedo change on surface temperatures. TIRS measures surface temperature at the
same portion of the surface where the albedo changes
are detected. This fact provides a unique opportunity
to study potential effects in surface temperature of
the observed change in albedo.

Figure 4. Diurnal amplitude of surface temperature as a function of surface albedo between sols 287
and 328 of the mission. Colors represent the downward radiation at 13 LMST.
Figure 4 shows the daily amplitude of the surface
temperature measured by TIRS as a function of the
surface albedo and incoming shortwave radiation
measured by RDS. The lowest diurnal amplitudes
occurred during sols 316 and 317, when opacity was
high and caused a significant decrease in downward
shortwave radiation (dark blue markers). When comparing sols with similar insolation (around 290 – 300
W/m2), the diurnal amplitudes increased from 86 –
88 K before the storm to 90-92 K after the storm.
This is consistent with a decrease in surface albedo:
for a given downward shortwave radiation, the darkened surface would absorb a larger fraction of incoming radiation, which could cause an additional
heating of the surface. The change in albedo could
modify the differences between surface and air temperatures, affecting atmospheric thermodynamical
processes.
Acknowledgments: This research has been
funded by the Spanish State Research Agency (AEI)
Project MDM-2017-0737 Unidad de Excelencia
“María de Maeztu”- Centro de Astrobiología
(CSIC/INTA). MEDA measurements can be found in
the
NASA
PDS
(https://pdsatmospheres.nmsu.edu/data_and_services/
atmospheres_data/PERSEVERANCE/meda.html).
References: [1] Rodriguez-Manfredi, J.A. et al.
(2021) Spa. Sci. Rev., 217, 48. [2] Bell, J.F. et al.
(2021) Spa. Sci. Rev., 217, 24. [3] Maki, J.N. et al.
(2020) Spa. Sci. Rev., 216, 137. [4] VicenteRetortillo, A. et al. (2022) GRL, in prep.

[5] Sebastián, E. et al. (2020) Measurement, 164,
107968. [6] Hueso, R. et al. (2022), JGR, in prep. [7]
Newman, C.E., et al. (2022), Sci. Adv., accepted. [8]
Vicente-Retortillo, A., et al., 53 LPSC, 2022. [9]
Sullivan, R. et al., 53 LPSC, 2022.