An updated seabed bathymetry beneath Larsen C Ice Shelf, Antarctic Peninsula
2020
Abstract. In recent decades, rapid ice shelf disintegration along
the Antarctic Peninsula has had a global impact through enhancing
outlet glacier flow and hence sea level rise and the freshening of
Antarctic Bottom Water. Ice shelf thinning due to basal melting results from
the circulation of relatively warm water in the underlying ocean cavity.
However, the effect of sub-shelf circulation on future ice shelf stability
cannot be predicted accurately with computer simulations if the geometry of
the ice shelf cavity is unknown. To address this deficit for Larsen C Ice
Shelf, West Antarctica, we integrate new water column thickness measurements
from recent seismic campaigns with existing observations. We present these
new data here along with an updated bathymetry grid of the ocean cavity. Key
findings include a relatively deep seabed to the southeast of the Kenyon
Peninsula, along the grounding line and around the key ice shelf
pinning-point of Bawden Ice Rise. In addition, we can confirm that the
cavity's southern trough stretches from Mobiloil Inlet to the open ocean.
These areas of deep seabed will influence ocean circulation and tidal
mixing and will therefore affect the basal-melt distribution. These results
will help constrain models of ice shelf cavity circulation with the aim of
improving our understanding of sub-shelf processes and their potential
influence on ice shelf stability. The datasets are comprised of all the new point measurements of seabed depth. We
present the new depth measurements here, as well as a compilation of
previously published measurements. To demonstrate the improvements to the
sub-shelf bathymetry map that these new data provide we include a gridded
data product in the Supplement of this paper, derived using
the additional measurements of both offshore seabed depth and the thickness
of grounded ice. The underlying seismic datasets that were used to
determine bed depth and ice thickness are available at
https://doi.org/10.5285/315740B1-A7B9-4CF0-9521-86F046E33E9A
(Brisbourne et al., 2019), https://doi.org/10.5285/5D63777D-B375-4791-918F-9A5527093298 (Booth,
2019), https://doi.org/10.5285/FFF8AFEE-4978-495E-9210-120872983A8D
(Kulessa and Bevan, 2019) and https://doi.org/10.5285/147BAF64-B9AF-4A97-8091-26AEC0D3C0BB
(Booth et al., 2019).
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