Numerical simulations of radar echoes rule out basal CO2 ice deposits at Ultimi Scopuli, Mars

Journal
Date Issued
2022
Author(s)
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Caprarelli, Graziella
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COSCIOTTI, BARBARA
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De Lorenzis, Alessandro
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De Nunzio, Giorgio
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Soldovieri, Francesco
DOI
Description
The authors are grateful to A.P. Rossi and L. Guallini for their helpful comments on an earlier version of this manuscript. We thank two anonymous reviewers for their constructive criticism and insights, that contributed to clarify and improve the paper. This work was supported by the Italian Space Agency (ASI) through contract ASI-INAF 2019–21- HH.0.
Abstract
The principal objective of the radar sounder MARSIS experiment is to look for ice and water in the Martian subsurface. One particular focus of investigations, since 2005, has been the search for basal liquid water in the south polar layered deposits (SPLD). Anomalously strong basal echoes detected from four distinct areas at the base of the deposits at Ultimi Scopuli have been interpreted to indicate the presence of bodies of liquid water in this location, beneath a 1.5 km thick cover of ice and dust. Other explanations for the bright basal reflections have been proposed, however, including the possibility of constructive interference in layered media. Here, we test this mechanism through simulations of MARSIS radar signals propagating in models of CO2-H2O ice sequences. We then compare the results to real MARSIS data acquired over Ultimi Scopuli, finding that no CO2-H2O ice model sequence reproduces the set of real data. The results of our work have implications in relation to the global CO2 inventory of Mars.
Volume
386
Start page
1
Uri
Url
Issn Identifier
0019-1035
Ads BibCode
2022Icar..38615163O
Rights
open.access
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