InSight Pressure Data Recalibration, and Its Application to the Study of Long-Term Pressure Changes on Mars

By Keith Cowing
Press Release
October 14, 2022
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InSight Pressure Data Recalibration, and Its Application to the Study of Long-Term Pressure Changes on Mars
a) Evolution of the ratio of MSL REMS pressure measurements interpolated to the InSight landing site, and InSight pressure measurements. Dots correspond to the ratio using the interpolation method described in section 2.1, i.e., neglecting atmospheric dynamic effects, during MY 34 (green), MY 35 (grey), and MY 36 (blue). b) Anomaly between the temperature of the GCM at an altitude of 1 km above the surface, and the temperature T∗ that gives a ratio of 1, as a function of Ls(colored curve) for MY 35. c) Comparison between InSight surface pressure over a complete sol and MSL pressure interpolated at InSight landing site between Ls= 275°and 280°, during MY 35. d) Extract of THEMIS image V63417011 of Gale Crater (center of the original image: 4.9°S;137.0°E ) taken at Ls= 130°, LTST = 7.2hr, with a solar incident angle of 74.5°. e) Extract of THEMIS image V65575024 at the same location, taken at Ls= 229°, LTST = 7.2hr, with a solar incident angle of 71.3°. The black arrow on e) points to the suspected aerosols, whereas the red arrows on d) and e) point to the same crater for a comparison of the perceptibility of the ground. White arrows point to the position of the Sun in the sky. – astro-ph.EP

Observations of the South Polar Residual Cap suggest a possible erosion of the cap, leading to an increase of the global mass of the atmosphere.

We test this assumption by making the first comparison between Viking 1 and InSight surface pressure data, which were recorded 40 years apart. Such a comparison also allows us to determine changes in the dynamics of the seasonal ice caps between these two periods.

To do so, we first had to recalibrate the InSight pressure data because of their unexpected sensitivity to the sensor temperature. Then, we had to design a procedure to compare distant pressure measurements. We propose two surface pressure interpolation methods at the local and global scale to do the comparison. The comparison of Viking and InSight seasonal surface pressure variations does not show changes larger than +-8 Pa in the CO2 cycle. Such conclusions are supported by an analysis of Mars Science Laboratory (MSL) pressure data.

Further comparisons with images of the south seasonal cap taken by the Viking 2 orbiter and MARCI camera do not display significant changes in the dynamics of this cap over a 40 year period. Only a possible larger extension of the North Cap after the global storm of MY 34 is observed, but the physical mechanisms behind this anomaly are not well determined. Finally, the first comparison of MSL and InSight pressure data suggests a pressure deficit at Gale crater during southern summer, possibly resulting from a large presence of dust suspended within the crater.

L. Lange, F. Forget, D. Banfield, M. Wolff, A. Spiga, E. Millour, D. Viúdez-Moreiras, A. Bierjon, S. Piqueux, C. Newman, J. Pla-García, W. B. Banerdt

Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2209.13412 [astro-ph.EP] (or arXiv:2209.13412v1 [astro-ph.EP] for this version)
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Journal reference: Journal of Geophysical Research (Planets), vol.127, pp.e07190 (2022)
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Submission history
From: Francois Forget
[v1] Tue, 27 Sep 2022 14:12:51 UTC (41,130 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻