BEDMAP: A new ice thickness and subglacial topographic model of Antarctica

TLDR

A comprehensive database of Antarctic ice‑sheet thickness measurements spanning five decades has been assembled. Using this database, the authors compiled a seamless suite of digital topographic models covering ice‑sheet thickness, bed elevation, water column thickness, and bathymetry to 60°S, including sub‑ice‑shelf cavities. The resulting BEDMAP grids, with a nominal 5‑km resolution, agree with recent high‑resolution surface elevation data, provide an unprecedented view of the sub‑glacial geosphere, estimate the Antarctic ice sheet volume at 25.4 million km³ and a sea‑level rise of 57 m (52 m East, 5 m West), and are publicly available.

Abstract

Measurements of ice thickness on the Antarctic ice sheet collected during surveys undertaken over the past 50 years have been brought together into a single database. From these data, a seamless suite of digital topographic models have been compiled for Antarctica and its surrounding ocean. This includes grids of ice sheet thickness over the grounded ice sheet and ice shelves, water column thickness beneath the floating ice shelves, bed elevation beneath the grounded ice sheet, and bathymetry to 60°S, including the sub‐ice‐shelf cavities. These grids are consistent with a recent high‐resolution surface elevation model of Antarctica. While the digital models have a nominal spatial resolution of 5 km, such high resolution is justified by the original data density only over a few parts of the ice sheet. The suite does, however, provide an unparalleled vision of the geosphere beneath the ice sheet and a more reliable basis for ice sheet modeling than earlier maps. The total volume of the Antarctic ice sheet calculated from the BEDMAP grid is 25.4 million km 3 , and the total sea level equivalent, derived from the amount of ice contained within the grounded ice sheet, is 57 m, comprising 52 m from the East Antarctic ice sheet and 5 m from the West Antarctic ice sheet, slightly less than earlier estimates. The gridded data sets can be obtained from the authors.