The cavity under the Amery Ice Shelf, East Antarctica

B. Galton-Fenzi , C. Maraldi (1) , R. Coleman (2) , J. Hunter

1 LEGOS - Laboratoire d'études en Géophysique et océanographie spatiales
2 Center for Marine Science

Ocean circulation under ice shelves and associated rates of melting and freezing are strongly influenced by the shape of the sub-ice-shelf cavity. We have refined an existing method and used additional in situ measurements to estimate the cavity shape under the Amery Ice Shelf, East Antarctica. A finite-element hydrodynamic ocean-tide model was used to simulate the major tidal constituents for a range of different sub-Amery Ice Shelf cavity water-column thicknesses. The data are adjusted in the largely unsurveyed southern region of the ice-shelf cavity by comparing the complex error between simulated tides and in situ tides, derived from GPS observations. We show a significant improvement in the simulated tides, with a combined complex error of 1.8 cm, in comparison with past studies which show a complex error of similar to 5.3 cm. Our bathymetry incorporates ice-draft data at the grounding line and seismic surveys, which have provided a considerable amount of new data. This technique has particular application when the water column beneath ice shelves is inaccessible and in situ GPS data are available.

Domaines: Océanographie

B. Galton-Fenzi, C. Maraldi, R. Coleman, J. Hunter. The cavity under the Amery Ice Shelf, East Antarctica. Journal of Glaciology, 2008, 54 (188), pp.881-887. ⟨hal-00406802⟩