The multibeam echosounder (MBES) raw data presented here were collected in the Southern Ocean (SO) within the ISOBatA PNRA project as part of the XXXVII Italian Antarctic Expedition aboard the icebreaker Laura Bassi. The data were collected with the EM304 system mounted on board, corrected for sound velocity, processed with Qimera and formatted as ASCII-XYZ grid. This dataset is part of the collection "ISOBaTA MBES GRID for IBCSO", which can be downloaded from SNAP and is searchable at https://antarcticdatacenter.inogs.it/.

The ISOBatA project (Italian Southern Ocean Bathymetry from consistent exploitation of opportunistic seafloor datasets in the Antarctic region and surrounding areas) introduced an innovative approach to optimize the collection of acoustic (mainly bathymetric) and magnetometric data. The main objective was to improve bathymetric knowledge of the Southern Ocean, focusing on unexplored areas such as the Ross Sea and the region between the Macquarie Triple Junction (MQ TJ) and the Emerald Fracture Zone (EMZ).

During the XXXVII expedition (2021-2022), dedicated ship time allowed for efficient data collection by reducing speed during transfers and adjusting routes along pre-determined corridors. Data acquisition was planned based on existing metadata: 1) IBCSO coverage and Italian MBES coverage, 2) Seismic Data Library (SDL) navigation, 3) Ross Sea Italian mooring sites, 4) italian coring sites and 5) ODP sites. The surveyed areas included transit routes through the Southern Ocean along MQ TJ and EMZ as well as previously unmapped areas in the Ross Sea, such as the Italian MORSEA moorings.

Acknowledgments: Special thanks go to the PNRA for funding and support and to the Laura Bassi research teams for their scientific interaction and collaboration.

Keywords: Southern Ocean, Bathymetry, ISOBatA, Laura Bassi, Antarctica, IBCSO.