Estimating the Volume of Capsizing Icebergs with Seismic Data
Abstract
One current concern in climate sciences is to reduce the uncertainties in sea level predictions. In particular, these uncertainties depend on the quantification of the mass balance of polar ice caps including Greenland ice sheet. Iceberg calving at Greenland tide water glaciers accounts for up to half of ice losses at glacier termini. A significant fraction of icebergs detached at glacier fronts are unstable and capsize close to the terminus. The contact between the iceberg and the terminus generates a seismic signal that can be recorded using seismic stations at teleseismic distances. The seismic signals contain a rich information about the dynamic of the iceberg capsize. The processes involved during icebergs capsize are complex - contacts between the glacier, the bedrock and the iceberg, elasto-viscoplastic deformation of the ice, and also the influence of the surrounding water environment; and only little field data is available. The global aim of this work is to invert information of the dynamic of the capsize based on seismic data to infer the volume and other characteristics of the icebergs. A simplified mechanical model of a capsizing iceberg in water has been developed, based on few simplifications: solving directly fluid, solid, and contact equations is very costly and hardly can be used to generate catalogues and to solve inverse problem. The proposed model, named SAFIM (semi-analytical floating iceberg model) accounts for the water flow only though hydrostatic pressure,pressure drag and added mass coefficients, and has been validated based on a separate state-of-the-art Computational Fluid Dynamic code, which can handle free surfaces, for several iceberg configurations. The SAFIM model is then used to invert seismic signals and to estimate the sizes of capsizing icebergs for few well-documented events.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C13A..07B
- Keywords:
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- 0720 Glaciers;
- CRYOSPHEREDE: 0758 Remote sensing;
- CRYOSPHEREDE: 0774 Dynamics;
- CRYOSPHEREDE: 0794 Instruments and techniques;
- CRYOSPHERE