P055-0007
Probing the atmosphere-driven ground motion through comodulation at InSight, Mars
Monday, 14 December 2020
Poster
Constantinos Charalambous1, Alexander Stott2, William T Pike2, John McClean2, Tristram Warren3, Aymeric Spiga4, Donald J Banfield5, Raphael F. Garcia6, John F Clinton7, Simon C Staehler8, Sara Navarro9, Philippe Henri Lognonné10, John-Robert Scholz11, Taichi Kawamura12, Martin van Driel8, Maren Böse7, Savas Ceylan13, Amir Khan8, Anna C Horleston14, Guenolé Orhand-Mainsant15, Luis Mora Sotomayor16, Naomi Murdoch17, Nils T Mueller18, Ozgur Karatekin19, Domenico Giardini20 and William Bruce Banerdt21, (1)Imperial College London, London, SW7, United Kingdom, (2)Imperial College London, London, United Kingdom, (3)Oxford University, Physics, Oxford, United Kingdom, (4)LMD/IPSL, Sorbonne Université, Paris, France - Institut Universitaire de France, France, Palaiseau Cedex, France, (5)Cornell University, Center for Radiophysics and Space Research, Ithaca, NY, United States, (6)Institut Supérieur de l'Aéronautique et de l'Espace, DEOS/SSPA, Toulouse Cedex 04, France, (7)ETH Swiss Federal Institute of Technology Zurich, Swiss Seismological Service (SED), Zurich, Switzerland, (8)ETH Zurich, Department of Earth Sciences, Institute of Geophysics, Zurich, Switzerland, (9)Centro de Astrobiologia (CSIC-INTA), Instrumentation, Madrid, Spain, (10)Université de Paris, Institut de physique du globe de Paris, CNRS, Paris, France, (11)Alfred Wegener Institute Helmholtz-Center for Polar and Marine Research Bremerhaven, Bremerhaven, Germany, (12)Université de Paris, Institut de physique du globe de Paris, Paris, France, (13)ETH Zurich, Zurich, Switzerland, (14)University of Bristol, Bristol, United Kingdom, (15)Institut Supérieur de l'Aéronautique et de l'Espace, Toulouse Cedex 04, France, (16)INTA-CSIC, Madrid, Spain, (17)Institut Supérieur de l’Aéronautique et de l’Espace, DEOS/SSPA, Toulouse, France, (18)German Aerospace Center DLR Berlin, Berlin, Germany, (19)Royal Observatory of Belgium, Brussels, Belgium, (20)Swiss Federal Institute of Technology (ETH), Zurich, Switzerland, (21)JPL/NASA/Caltech, Pasadena, CA, United States
Abstract:
Noise is a ubiquitous source of signal interference for a diverse range of environments. For InSight, NASA's lander on Mars, the atmosphere is a significant noise contributor impeding the identification of seismic events for most of the Martian day. The superposition of environmental noise injection with signals of interest makes separation a challenging task. In this work, we deconstruct this superposition with a novel approach in which we partition the signal into seismic and environmental contributions. We do this through comodulation, an approach adapted from psychophysical processes and the human auditory system, where the perceptual comparison of sound by energy content reflects both the time and frequency information in the signal. Our comodulation approach allows us to observe the injection of wind and pressure into the seismic response from 0.01Hz to 50Hz over a full Martian year, in terms of correlations in their signal power within and across frequencies.
We begin by exploring relationships between the atmosphere and ground motion which exhibit evolving interactions over the day-to-day Martian cycle, but also seasonally. We observe that the ground motion intensity is defined by a temporal coupling behaviour driven by external parameters such as air temperature and density, surface temperature and wind direction. We subsequently exploit the atmosphere-ground coupling to identify various atmospheric phenomena and attribute sources to observed features in the seismic record. Finally, we introduce important applications of our approach, such as the discrimination of seismic events from potential atmospheric sources. The divergence in the matched trajectory of the comodulated atmospheric and seismic signal power helps identify and constrain the timing of seismic phases, also allowing us to obtain a unique environmental signal-to-noise ratio (SNR). Our approach can further constrain events into optimal frequencies allowing for minimum superposition of seismic and noise signals, thus improving the SNR.
Our findings bring important implications to future planetary missions, but also on Earth, particularly in scenarios where synchronous environmental measurements by multiple sensors can provide the inputs required to exploit and reveal unique features of both the subsurface and the environment.
