Bathymetry Beneath the Amery Ice Shelf, East Antarctica, Revealed by Airborne Gravity

Yang, Junjun; Greenbaum, J. S.; Cui, Xiangbin; Tu, Liangcheng; Li, Lin; Jong, Lenneke M.; Tang, Xueyuan; Li, Bingrui; Blankenship, D. D.; Roberts, Jason L.; Sun, Bо

doi:10.1029/2021gl096215

Cited by 9 publications

(12 citation statements)

References 56 publications

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“…Basal melting rate(m yr -1 ) Meltwater flux(Gt yr -1 ) Differences of basal melting rate (%) The basal melt rate (m yr -1 , melting is positive) of the AIS in ( Yang et al, 2021), the drifting and grounding icebergs (Dinniman et al, 2007;Cougnon et al, 2017;Hou and Shi, 2021), and the distribution of fast ice (Fraser et al, 2021). With a focus on the effects of the bathymetry changes on the shelf circulations and the ice shelf basal melting, this study is an important first step towards a comprehensive understanding of the effects of such various factors.…”

Section: Ice Shelfmentioning

confidence: 99%

“…To construct an improved bathymetry data set for the Antarctic shelf seas, it is a conventional and effective way of conducting the single beam and multibeam measurements with shipborne echo soundings during a number of expeditions (Nitsche et al, 2007;Beaman et al, 2011;Graham et al, 2011;Dickens et al, 2014;Smith et al, 2021). Airborne gravity provides an efficient remote sensing approach to reconstruct the detailed geometry of sub-ice-shelf cavities (Millan et al, 2017;Cochran et al, 2020;Millan et al, 2020;Eisermann et al, 2021;Yang et al, 2021). Importantly, marine mammals equipped with conductivity-temperaturedepth satellite relay data loggers (CTD-SRDLs), which have greatly enriched the traditional hydrographic data sets (Hooker and Boyd, 2003;Padman et al, 2010;Herraiz-Borreguero et al, 2016;Williams et al, 2016) , also offer the further possibility to explore the bathymetry of the Antarctic continental shelf.…”

Section: Introductionmentioning

confidence: 99%

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On the influences of the continental shelf bathymetry correction in Prydz Bay, East Antarctica

et al. 2022

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The bathymetry around Antarctica can govern the shelf sea circulations and play a key role in conditioning water masses. In Prydz Bay, the Prydz Bay Gyre and coastal currents are also determined by the continental shelf topography. However, due to the paucity of beam echo sounding data, the bathymetric datasets in Prydz Bay still have large uncertainties. With the aid of in situ hydrographic observations, this study focuses on the correction of an up-to-date bathymetric dataset and the resultant influences on the shelf circulation and the basal melting of the ice shelves. The corrected bathymetry mainly improves the biased shallow representations in the uncorrected bathymetric data set, with a maximum change of ~500 m deepening in the eastern flank of Prydz Bay. Sensitivity numerical experiments show that the bathymetric corrections in Prydz Bay have a significant impact on the circulation pattern and onshore warm water intrusions. In addition, the corrected bathymetry markedly decreases the heat transport towards the calving front of the Amery Ice Shelf. The onshore heat transport reduces by ~22.18% from ~5.23×1013 J s-1 to ~4.07×1013 J s-1 over the outer shelf. Over the inner shelf, the heat transport towards the Amery Ice Shelf reduces by ~18.15% from ~5.95×1013 J s-1 to ~4.87×1013 J s-1. Consequently, the temporally and spatially averaged basal melting rate of the Amery Ice Shelf reduces by ~13.04% from ~0.69 m yr-1 to ~0.60 m yr-1.

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Section: Ice Shelfmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On the influences of the continental shelf bathymetry correction in Prydz Bay, East Antarctica

et al. 2022

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“…The mass loss process of basal melting dominates Antarctica’s ice shelves 3 and has proven to be highly dependent on water temperatures in the cavities beneath them 4 and their underlying bathymetry 5 , 6 . Bedrock topography not only controls the circulation of water within a cavity between seabed and ice base, but is also a deciding factor on whether and where warm oceanic water residing at intermediate depths along the coast breaches into that cavity 7 – 9 . Offshore, bathymetry influences current steering and upwelling patterns and, consequently, the overall oceanographical setting at the coast.…”

Section: Introductionmentioning

confidence: 99%

Coastal bathymetry in central Dronning Maud Land controls ice shelf stability

Eisermann,

Eagles,

Jokat

2024

Sci Rep

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Knowledge of the bathymetry of Antarctica’s margins is crucial for models and interpretations of ice-ocean interactions and their influence on ongoing and future sea level change, but remains patchy where ice shelves and multi-year sea ice block measurements. Here, we present a bathymetric model for the central Dronning Maud Land margin, based on a constrained inversion of airborne gravity data. It shows the cavities beneath the region’s two ice shelves to be much deeper than in existing bathymetric compilations, but to be shielded from Warm Deep Water ingress and basal melting by the presence of shallow bathymetric sills along the continental shelf. Over areas of multi-year sea ice, the model returns bathymetric estimates of similar accuracy to gravity interpolation-based methods over open water. Airborne gravity thus presents an opportunity to bathymetrically map hundreds of thousands of square kilometres of the most inaccessible margins of Antarctica at resolutions adequate for regional and global oceanographic and glaciological modelling and interpretation.

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“…If this data is sparse, or the constrained points are not located near gravity observation points, some inaccuracies will be introduced. This technique has been used in several bathymetry inversions (An et al, 2019a;Millan et al, 2020;Yang et al, 2021).…”

Section: Constraint Point Minimizationmentioning

confidence: 99%

“…Pritchard et al, 2012;Tinto et al, 2019). Additionally, deep bathymetric troughs in regions of otherwise thin drafts, or conversely, bathymetry ridges in regions of thick drafts, can control the incursion of these water masses (St-Laurent et al, 2013;Yang et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

Airborne Geophysical Investigation beneath Antarctica's Ross Ice Shelf

Tankersley

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The Ross Ice Shelf controls the flow of ice into the ocean from catchments consisting of both the East and West Antarctic Ice Sheets. These catchments hold a volume of ice equivalent to ∼12 m of global sea level rise. To adequately understand how this ice will respond to a warming world requires knowledge of the properties and parameters which influence how the ice sheet behaves. These boundary conditions include fundamental knowledge of the Earth, such as the shape of the bed beneath the ice, the seafloor, and the geologic structures of the upper crust. Knowledge of the physiography and sub-surface geology is severely lacking beneath ice shelves due to their inaccessibility.Here, we use airborne geophysical data from an extensive survey over the Ross Ice Shelf to better understand these boundary conditions. From the analysis of airborne magnetics data, we model the thickness of sediment, the shape of the crystalline basement, and the likely locations of faults throughout the crust under the Ross Ice Shelf. We find a continuous drape of sediment over the seafloor, including deep and narrow fault-bound sedimentary basins beneath the Siple Coast.Using airborne gravity data, and distributed seismic constraints over the ice shelf, we develop and implement a gravity inversion to recover a higher-resolution bathymetry model beneath the ice shelf. This bathymetry model and our quantifica- tion of spatial uncertainty highlight locations likely important for sub-ice shelf ocean circulation and possible recent pinning points. In the process of these geophysical investigations, we reveal a wide range of insights relating to how bathymetry and geology play a critical role in the past, present, and future dynamics of the ice sheet, and how this region has developed over its tectonic history.

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Bathymetry Beneath the Amery Ice Shelf, East Antarctica, Revealed by Airborne Gravity

Cited by 9 publications

References 56 publications

On the influences of the continental shelf bathymetry correction in Prydz Bay, East Antarctica

On the influences of the continental shelf bathymetry correction in Prydz Bay, East Antarctica

Coastal bathymetry in central Dronning Maud Land controls ice shelf stability

Airborne Geophysical Investigation beneath Antarctica's Ross Ice Shelf

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