The ocean plays an important role in modulating the mass balance of the polar
ice sheets by interacting with the ice shelves in Antarctica and with the
marine-terminating outlet glaciers in Greenland. Given that the flux of warm
water onto the continental shelf and into the sub-ice cavities is steered by
complex bathymetry, a detailed topography data set is an essential ingredient
for models that address ice–ocean interaction. We followed the spirit of the
global RTopo-1 data set and compiled consistent maps of global ocean
bathymetry, upper and lower ice surface topographies, and global surface
height on a spherical grid with now 30 arcsec grid spacing. For this new
data set, called RTopo-2, we used the General Bathymetric Chart of the Oceans
(GEBCO_2014) as the backbone and added the International Bathymetric Chart
of the Arctic Ocean version 3 (IBCAOv3) and the International Bathymetric
Chart of the Southern Ocean (IBCSO) version 1. While RTopo-1 primarily aimed
at a good and consistent representation of the Antarctic ice sheet, ice
shelves, and sub-ice cavities, RTopo-2 now also contains ice topographies of
the Greenland ice sheet and outlet glaciers. In particular, we aimed at a
good representation of the fjord and shelf bathymetry surrounding the
Greenland continent. We modified data from earlier gridded products in the
areas of Petermann Glacier, Hagen Bræ, and Sermilik Fjord, assuming that
sub-ice and fjord bathymetries roughly follow plausible Last Glacial Maximum
ice flow patterns. For the continental shelf off Northeast Greenland and the
floating ice tongue of Nioghalvfjerdsfjorden Glacier at about 79° N,
we incorporated a high-resolution digital bathymetry model considering
original multibeam survey data for the region. Radar data for surface
topographies of the floating ice tongues of Nioghalvfjerdsfjorden Glacier and
Zachariæ Isstrøm have been obtained from the data centres of Technical
University of Denmark (DTU), Operation Icebridge (NASA/NSF), and Alfred
Wegener Institute (AWI). For the Antarctic ice sheet/ice shelves, RTopo-2
largely relies on the Bedmap-2 product but applies corrections for the
geometry of Getz, Abbot, and Fimbul ice shelf cavities. The data set is
available in full and in regional subsets in NetCDF format from the PANGAEA
database at
doi:10.1594/PANGAEA.856844.