A Comodulation Analysis of Atmospheric Energy Injection Into the Ground Motion at InSight, Mars

Abstract

• A comodulation analysis is implemented to describe and interpret the sensitivity of InSight's seismometers to atmospheric energy injection • The seismic response of InSight to the wind and pressure is observed to vary diurnally and seasonally depending on atmospheric conditions • The power from the wind and pressure signals injected into seismic events is quantified to assess marsquake discrimination

Vortex‐Dominated Aeolian Activity at InSight's Landing Site, Part 1: Multi‐Instrument Observations, Analysis, and Implications

“…The core pressure drop then allows the tangential wind speed to be estimated for both distant and near‐lander encounters. Second, since seismic data is recorded at 100 sps in comparison to 1 sps TWINS data, instantaneous peak wind speeds during close vortex encounters may be retrievable through comodulation, a framework in which SEIS is used as a wind sensor (Charalambous et al., 2020). Comodulation may also provide redundancy in the wind speed and pressure measurements by detecting vortices without APSS, potentially allowing SEIS to behave as a meteorological, in addition to a seismological, instrument.…”

“…Due to its very high sensitivity, SEIS is capable of detecting atmospheric phenomena such as convective vortices, infrasound, and gravity waves. As such, recent studies have utilized SEIS as a meteorological instrument (Banerdt et al., 2020; Charalambous et al., 2020; Martire et al., 2020). The passage of a convective vortex, regardless of its dust content, provides a negative load that causes an elastic response in the ground detected seismically as a tilt (Lorenz et al., 2015) allowing tracking of vortices more effectively than possible with a meteorological package (Lorenz et al., 2015).…”

“…Since the tether is connected to SEIS and is sensitive to electric fields, charged grains could induce an electric field noise detectable by SEIS (Clinton et al., 2017). Comodulation approaches (Charalambous et al., 2020), together with polarization analysis (Stutzmann et al., 2020), can help identify seismic signals originating from such sources. These could help identify and constrain the timing of events such as the putative saltation impacts on the SEIS tether during sol 235, and whether these originated from ejections from a distant vortex identifiable as a precursor in the ground tilt sensed by SEIS.…”

“…Hence, InSight is ideally suited to monitor local aeolian changes with combined imaging, meteorological, surface, and magnetic measurements (Spiga et al., 2018). Furthermore, solar array currents can be used for atmospheric investigations (Lorenz, Lemmon, et al., 2020), and seismic data from SEIS can be used to study induced ground motion from short‐lived atmospheric phenomena, such as convective vortices and turbulent wind gusts, as well as longer‐scale ambient, acoustic and gravity waves (e.g., Charalambous et al., 2020; Lognonne et al., 2020; Murdoch et al., 2020).…”

Seasonal Variability of the Daytime and Nighttime Atmospheric Turbulence Experienced by InSight on Mars

“…daytime convective PBL before the nighttime development of the nocturnal low-level jet (Joshi et al, 1997;Savijärvi & Siili, 1993), during which weaker turbulence than in the daytime is experienced by InSight sensors (Charalambous et al, 2021;Garcia et al, 2020). Apart from its interest for Mars' weather, studying PBL turbulence is key to characterizing atmosphere-induced seismic noise (Ceylan et al, 2021;Stutzmann et al, 2021).…”