Advancements with SpATIaL: Semi-Automatic glacier Terminus Inventory from Landsat
Abstract
Glacier terminus position change represents a complex response to the interaction between ice sheet, ocean, atmosphere, and sedimentary environments. Dynamic change to the marine margins of outlet glaciers has been responsible for a large portion of the mass loss from the Greenland ice sheet (GrIS) over the past two decades. Terminus retreat influences upstream thinning and acceleration, which in turn, causes additional ice loss. Observations of terminus position change compared to bed geometry, ice mélange presence, and the timing of meltwater runoff suggest that a detailed reconstruction of terminus positions can be useful to quantify the controls on outlet glacier dynamics in GrIS. However, the time required to hand-pick glacier termini puts a limit on how rapidly this analysis can be completed. Here we present a semi-automated algorithm that enables terminus identification using Landsat 8 multispectral imagery for several glaciers in central West GrIS. Front delineation is achieved through digital image processing techniques, such as edge and morphological operators in order to locate the highest intensity changes within a fjord, which is generally the boundary between glacier ice and water or ice melange. Currently, our semi-automatically picked glacier termini is effective in clear late spring to early fall images, but the presence of heavy ice mélange, abundant icebergs, low solar illumination, or shadows can create false or zero picks. We anticipate exploring other computer vision techniques for distinguishing the terminus position for these more challenging scenarios in the near future.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFM.C11C1125G
- Keywords:
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- 0758 Remote sensing;
- CRYOSPHEREDE: 0762 Mass balance;
- CRYOSPHEREDE: 0774 Dynamics;
- CRYOSPHEREDE: 0776 Glaciology;
- CRYOSPHERE