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

Measurements of ice thickness on the Antarctic ice sheet collected during s urveys undertaken over the past 50 years have been brought together into a single database. From these data, a seamless suite of digital topographic m odels have been compiled for Antarctica and its surrounding ocean. This inc ludes grids of ice sheet thickness over the grounded ice sheet and ice shel ves, water column thickness beneath the floating ice shelves, bed elevation beneath the grounded ice sheet, and bathymetry to 60 degreesS, including t he sub-ice-shelf cavities. These grids are consistent with a recent high-re solution surface elevation model of Antarctica. While the digital models ha ve 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 su ite 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 BEDM AP 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, co mprising 52 m from the East Antarctic ice sheet and 5 m from the West Antar ctic ice sheet, slightly less than earlier estimates. The gridded data sets can be obtained from the authors.