Mapping the Tidewater Submarine and Ice-Marginal Environment Using Interferometric Bathymetry, Ground-Based LiDAR and Current Velocities; Hubbard Glacier, Alaska
Abstract
The seasonal advance and retreat of tidewater glaciers is a relatively well-documented phenomenon. But our understanding of the processes and conditions within the ice-marginal submarine environment that drive or result from this activity is limited. Capturing holistic information within this environment such as bathymetric topography, hydrographic measurements and geospatial information about the terminus itself is often limited to discrete measurements far from the terminus grounding line or lack the detail and scale necessary to identify features that may be indicative of process. To understand these processes, it is essential to accurately obtain data at resolutions that are sufficient to understand the geologic and marine environment. This paper describes the results of a first-of-its-kind survey of the submarine and ice-marginal terrestrial environment of the Hubbard Glacier tidewater terminus. Hubbard Glacier is the largest non-polar tidewater glacier in the world. It encompasses an area of 3500 sq km and flows 120 km from the flanks of Mt Logan (5959 m) in the Wrangell St. Elias Mountains (Canada) to sea level where its terminus widens to ~13 km. In contrast to most glaciers in Southeast Alaska, Hubbard Glacier continues to advance and thicken and is predicted to continue for the foreseeable future. We utilize a multi-sensor fusion approach that integrates high-resolution interferometric (swath-based) multibeam bathymetry with high-resolution ground-based LiDAR topography and current velocity profiles to provide a detailed look at the section of the glacier where significant ice advance and potential ice-damming occurs. Through simultaneous collection of these data we are able to precisely map the topography of the sea floor adjacent to and at the grounding line of the ice terminus while simultaneously mapping the ice terminus and surrounding terrain to create a complete 3D topographic model of the aerial and submarine environment. These data allow for characterization of sediment accumulations and bed morphologies related to seasonal glacier advance and retreat and identification of influential geologic features and hydrologic characteristics. Our investigations address an important yet lacking realm of data collection technologies that can be integrated to provide a holistic view of the tidewater glacier environment.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2009
- Bibcode:
- 2009AGUFM.C12A..08F
- Keywords:
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- 0720 CRYOSPHERE / Glaciers;
- 0774 CRYOSPHERE / Dynamics;
- 0776 CRYOSPHERE / Glaciology;
- 0794 CRYOSPHERE / Instruments and techniques