New open source tools for MARSIS: providing access to SEG-Y data format for 3D analysis.

The objective of this work is to present a new Free and Open-Source Software (FOSS) to read and convert to multiple data formats data acquired by the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS) instrument on board Mars Express (MEX) orbiting Mars since 2005.

MARSIS is an orbital synthetic aperture radar sounder that operates with dual-frequency between 1.3 and 5.5 MHz and wavelengths between 230 and 55 m for subsurface sounding. The Experiment Data Record (EDR) and Reduced Data Record (RDR) datasets are available for download on public access platforms such as the Planetary Science Archive fo ESA and the PDS-NASA Orbital Data Explorer (ODE).

These datasets have been widely used for different research, focused to study the subsurface of the red planet up to a depth of a few kilometres, and especially for studying ice caps and looking for subsurface ice and water deposits, producing relevant results. (Lauro et al., 2020; Orosei et al., 2020)

The Python tool presented here is capable of reading common data types used to distribute MARSIS dataset and then converting into multiple data formats. Users can interactively configure data source, destination, pre-processing and type of outputs among:

• Geopackages: for GIS software, is a single self-contained file containing a layer in which are stored all parameters for each file processed.
• Numpy array dump: for fast reading and analysis of original data for both frequencies.
• PNG images: for fast inspections, created for each frequency, and saved. Image pre-processing filters, such as image-denoising, standardization and normalization, can be selected by user.
• SEG-Y: for analysing data with seismic interpretation and processing software, see e.g. OpendTect, consist of a SEG-Y file for each frequency.

SEG-Y capability is the most relevant feature, since is not present in any of other FOSS tool and give to researchers the possibility to visualize radargrams in advanced software, specific for seismic interpretation and analysis, making it possible to interpret the data in a fully three-dimensional environment.

This tool, available on zenodo (Nodjoumi, 2021), has been developed completely in Python 3, relying only on open-source libraries, compatible with principal operating systems and with parallel processing capabilities, granting easy scalability and usability across a wide range of computing machines. It is also highly customizable since it can be expanded adding processing steps before export or new types of output. An additional module to ingest data directly into PostgreSQL/PostGIS and a module to interact directly with ACT-REACT interface of data platforms are under development.

Acknowledgments:

This study is within the Europlanet 2024 RI, and it has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No 871149. 

References:

Lauro, S. E. et al. (2020) ‘Multiple subglacial water bodies below the south pole of Mars unveiled by new MARSIS data’, doi: 10.1038/s41550-020-1200-6.

Nodjoumi, G. (2021) 'MARSIS-xDR-READER', doi: 10.5281/zenodo.4436199

Orosei, R. et al. (2020) ‘The global search for liquid water on mars from orbit: Current and future perspectives’, doi: 10.3390/life10080120.