Gravity-derived Antarctic bathymetry using the Tomofast-x open-source code: a case study of Vincennes Bay

Abstract

Vincennes Bay is a region of East Antarctica that is vulnerable to sub-ice-shelf basal melting from warm ocean water intrusions. The sub-ice-shelf bathymetry in this region is largely unknown despite its importance for ocean dynamics within ice shelf cavities and associated sub-ice-shelf basal melting. Here, we present an open-source approach to deriving open-ocean and sub-ice-shelf bathymetry from airborne gravity data using the Tomofast-x inversion platform. Using existing datasets of bed topography, bathymetry, ice geometry, instrumented seal dives, and airborne gravity data, we perform a constrained gravity inversion to generate a new bathymetry for Vincennes Bay. Our new bathymetry reveals large-scale bathymetric features, some of which were previously known to exist but were not resolved in existing regional bathymetry datasets, including the deep marine trough recently mapped offshore the Vanderford Glacier. A smaller and previously unknown bathymetric trough that reaches depths of more than 1500 m offshore the Adams Glacier is also identified. Ocean modelling using the new bathymetry simulates a 37 % increase in sub-ice-shelf melt rates compared with estimates generated using existing regional bathymetry datasets, highlighting the importance of more accurate bathymetry estimates in this region.