Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 11, 363-380, 2017
http://www.the-cryosphere.net/11/363/2017/
doi:10.5194/tc-11-363-2017
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
01 Feb 2017
Generating synthetic fjord bathymetry for coastal Greenland
Christopher N. Williams1, Stephen L. Cornford1, Thomas M. Jordan1, Julian A. Dowdeswell2, Martin J. Siegert3, Christopher D. Clark4, Darrel A. Swift4, Andrew Sole4, Ian Fenty5, and Jonathan L. Bamber1 1Bristol Glaciology Centre, School of Geographical Sciences, University of Bristol, Bristol, UK
2Scott Polar Research Institute, University of Cambridge, Cambridge, UK
3Grantham Institute, and Department of Earth Science and Engineering, Imperial College London, London, UK
4Department of Geography, The University of Sheffield, Sheffield, UK
5Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
Abstract. Bed topography is a critical boundary for the numerical modelling of ice sheets and ice–ocean interactions. A persistent issue with existing topography products for the bed of the Greenland Ice Sheet and surrounding sea floor is the poor representation of coastal bathymetry, especially in regions of floating ice and near the grounding line. Sparse data coverage, and the resultant coarse resolution at the ice–ocean boundary, poses issues in our ability to model ice flow advance and retreat from the present position. In addition, as fjord bathymetry is known to exert strong control on ocean circulation and ice–ocean forcing, the lack of bed data leads to an inability to model these processes adequately. Since the release of the last complete Greenland bed topography–bathymetry product, new observational bathymetry data have become available. These data can be used to constrain bathymetry, but many fjords remain completely unsampled and therefore poorly resolved. Here, as part of the development of the next generation of Greenland bed topography products, we present a new method for constraining the bathymetry of fjord systems in regions where data coverage is sparse. For these cases, we generate synthetic fjord geometries using a method conditioned by surveys of terrestrial glacial valleys as well as existing sinuous feature interpolation schemes. Our approach enables the capture of the general bathymetry profile of a fjord in north-west Greenland close to Cape York, when compared to observational data. We validate our synthetic approach by demonstrating reduced overestimation of depths compared to past attempts to constrain fjord bathymetry. We also present an analysis of the spectral characteristics of fjord centrelines using recently acquired bathymetric observations, demonstrating how a stochastic model of fjord bathymetry could be parameterised and used to create different realisations.

Citation: Williams, C. N., Cornford, S. L., Jordan, T. M., Dowdeswell, J. A., Siegert, M. J., Clark, C. D., Swift, D. A., Sole, A., Fenty, I., and Bamber, J. L.: Generating synthetic fjord bathymetry for coastal Greenland, The Cryosphere, 11, 363-380, doi:10.5194/tc-11-363-2017, 2017.
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Short summary
Knowledge of ice sheet bed topography and surrounding sea floor bathymetry is integral to the understanding of ice sheet processes. Existing elevation data products for Greenland underestimate fjord bathymetry due to sparse data availability. We present a new method to create physically based synthetic fjord bathymetry to fill these gaps, greatly improving on previously available datasets. This will assist in future elevation product development until further observations become available.
Knowledge of ice sheet bed topography and surrounding sea floor bathymetry is integral to the...
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