Publication Date:
2021-10-18
Description:
The stability of ice shelves and drainage of ice sheets they buttress is largely determined by
melting at their atmospheric and oceanic interfaces. Subglacial bathymetry can impact ice shelf stability
because it influences the onset and the pattern of warm ocean water incursions into the cavities between
them and the seafloor. Bathymetry is further important at pinning points, which significantly retard the
flow of ice shelves. This effect can be lost instantaneously if basal and surface melting cause an ice sheet
to thin and lift off its pinning points. With all this in mind, we have developed a model of bathymetry
beneath the western Roi Baudouin and central and eastern Borchgrevink ice shelves in Dronning Maud
Land based on inversion from gravity data and tied to available depth references offshore and subglacial
topography inland of the grounding line. The model shows deep glacial troughs beneath the ice shelves
and bathymetric sills close to the continental shelf. The central Borchgrevink Ice Shelf overhangs the
continental slope by around 50km, exposing its northern parts to the open ocean and higher ocean
temperatures. Continuous troughs traverse the central Borchgrevink and western Roi Baudouin ice
shelves at depths greater than the offshore thermocline and thus present a risk of Warm Deep Water
intrusions into their cavities under the current and future oceanographic regimes. Differing bathymetric
characteristics might explain the ice shelves' contrasting dominant mass loss processes.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
peerRev
Format:
application/pdf
