PNAS (2025) https://doi.org/10.1073/pnas.2511744122 https://orfeo.belnet.be/handle/internal/14418
Daniel Viúdez-Moreiras, Michael D. Smith, Mike Wolff, Megan A. J. Brown, Frank Daerden, María-Paz Zorzano, Víctor Apestigue, Ignacio Arruego, Elisa García, Juan J. Jiménez, Daniel Toledo, Mark T. Lemmon, Elise Wright Knutsen, and Alfonso Saiz-Lopez
Ozone plays a key role in both atmospheric and near-surface chemistry, as well as in UV absorption in planetary atmospheres. We report observations of ozone from the surface of another planet using the ozone detector aboard NASA’s Mars 2020 mission. Total column measurements acquired at Jezero Crater, together with previous space-based observations, indicate that most of the observed ozone is confined below 20 km of altitude, strongly differing from the typical ozone vertical profile in the Earth atmosphere. Also, these ozone levels below 20 km are several times higher than those predicted by models, challenging the current understanding of atmospheric chemistry and composition in the lower atmosphere of Mars.
Vertical column density (VCD) measurements of ozone at low zenith angles (<3°), acquired between mission sols 65 and 290 (~37° < Ls < ~139°) (northern spring and summer), as a function of LTST, totaling 116 photometric observations. The mean abundance is shown by a red dashed line. 1σ error bars are shown, dominated by systematic uncertainties (~2 μm-atm) which mainly come from absolute calibration of the instrument. The top panels show the expected O3 mixing ratio in both the UT (>20 km) and the near-surface in the tropical region, simulated by JPL/Caltech KINETICS model. Each layer contributes variable to the total column abundance throughout the day, expecting predominance in the Mars 2020 observations by the LT layer. The green shadowed area is the sampled diurnal timeslot by Mars 2020 (11 to 13 h LTST). The red arrows represent the timings where vertical profiles are retrieved by orbiters in the UT. Two groups are established, in accordance with Table 1 (35° < Ls < 90° and 110° < Ls < 140°) (black and red dots, respectively), observing a clear drop in column abundances in the second group of measurements.