Ice Surface Elevation Changes in the Amundsen Sea Embayment, Antarctica from High-Resolution Satellite Derived Digital Elevation Models
Abstract
Glaciers around the Amundsen Sea Embayment of West Antarctica are experiencing rapid dynamic changes which have the potential to raise sea level around the globe as a result of their unprecedented ice mass loss into the Southern Ocean. Bedrock Global Positioning System (GPS) sites deployed by the Polar Earth Observing Network around the area are recording the fastest uplift rates on Earth, with the fastest site at Toney Mountain, near the Smith and Kohler Glaciers, on the western side of the embayment. We use a combination of high resolution Digital Elevation Models (DEMs) and firn & climate models to identify load changes in the region and correlate these to observed changes in the GPS signal. DEMs are optically derived from DigitalGlobe imagery and are generated using the open source algorithm SETSM at a resolution of 2 m. These are co-registered over bedrock to NASA IceBridge and CryoSat-2 altimetry measurements. DEMs located in the regions around the GPS sites are differenced to allow ice surface elevation changes (dh/dt) to be calculated and combined with bed elevations from Bedmap2 to generate volume changes (dV/dt). Firn density models and climate data from RACMO, are used to correct for elevation changes caused by variations in seasonal snowfall patterns and combined with the volume change (dV/dt) measurements from the DEMs to generate mass load changes. We see dynamic thinning signals in the region, especially over the fast-moving ice streams such as Thwaites and Pine Island Glaciers and compare our results with those obtained from CryoSat-2 and ICESat. Establishing the nature of ice load changes around the POLENET GPS sites enables us to more accurately constrain the response of the lithosphere to ice sheet unloading, investigating glacial isostatic adjustment (GIA) and instantaneous elastic response to load changes. Our work impacts Antarctic GIA models, GRACE calculations, and provides additional material to the study of uplift rates in the Amundsen Sea Embayment that have recently been suggested to be so rapid due to the presence of a low viscosity upper mantle.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C11C1130H
- Keywords:
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- 0758 Remote sensing;
- CRYOSPHEREDE: 0762 Mass balance;
- CRYOSPHEREDE: 0774 Dynamics;
- CRYOSPHEREDE: 0776 Glaciology;
- CRYOSPHERE