BedMachine v3: Complete bed topography and ocean bathymetry mapping of Greenland from multi-beam echo sounding combined with mass conservation

摘要

Greenland's bed topography is a primary control on ice flow, grounding line migration, calving dynamics and subglacial drainage. Moreover, fjord bathymetry regulates the penetration of warm Atlantic Water (AW) that rapidly melts and undercuts Greenland's marine-terminating glaciers. Here, we present a new compilation of Greenland bed topography that assimilates seafloor bathymetry and ice thickness data through a mass conservation (MC) approach. A new 150-m horizontal resolution bed topography/bathymetric map of Greenland is constructed with seamless transitions at the ice/ocean interface, yielding major improvements over previous datasets, particularly in the marine-terminating sectors of northwest and southeast Greenland. Our map reveals the total sea level potential of the Greenland Ice Sheet is 7.42±0.05 m, which is 7 cm greater than previous estimates. Furthermore, it explains recent calving front response of numerous outlet glaciers and reveals new pathways by which AW can access glaciers with marine-based basins, thereby highlighting sectors of Greenland that are most vulnerable to future oceanic forcing.