[astro-ph.EP]. During the initiation phase of Martian dust storms, a spectral signature of a zonal wavenumber 1 normal mode Kelvin wave (K1) has been observed in several surface pressure records.
However, the K1 signal has not been extracted directly since its eigenfrequency is close to that of the diurnal tide, making their separation difficult. We apply singular spectrum analysis to more than one Martian year of InSight surface pressure observations, including the MY34 C dust storm (C34).
This analysis enables us to directly extract the transient K1 signal. Clear K1 signals appear during the Northern-Hemisphere spring and autumn with the average amplitudes of around 2 Pa.
They reach 8 Pa during the C34 storm, which is substantial compared with a simultaneous diurnal signal (S1) maximum of 39 Pa. Near the peak time, K1 and S1 are in phase, and unexpectedly the S1 period shortens to 23.5 Mars hours. Subsequently, K1 rapidly decays and the S1 period recovers to 24 Mars hours.
The phase relation between K1 and S1 as well as the S1 period shortening indicates that a resonance occurred between S1 and K1. Comparison with simulations at the model grid point closest to the InSight landing site shows that the Mars Planetary Climate Model realistically reproduces the observed characteristics of the surface pressure variations.
Periodogram of Power Spectral Density (PSD) as a function of frequency (cycles per sol) for a ~29-sol interval with continuous coverage (ID#07). The thick gray curve shows the PSD of the original data, and the red curve shows the PSD of the reconstructed signal using the first 30 SSA modes. — [astro-ph.EP]
Anzu Asumi, Jorge Hernández-Bernal, Kaoru Sato, Aymeric Spiga
Comments: 25 pages, 1 table, 5 figures
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2608.19892 [astro-ph.EP] (or arXiv:2608.19892v1 [astro-ph.EP] for this version)
https://doi.org/10.48550/arXiv.2608.19892
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Submission history
From: Anzu Asumi
[v1] Thu, 20 Aug 2026 11:01:36 UTC (837 KB)
https://arxiv.org/abs/2608.19892
Astrobiology,
